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• What Makes a Good Design Critic? CHI 2010 Panel Review

  - by Applications User Experience

  Author: Daniel Schwartz, Senior Interaction Designer, Oracle Applications User Experience Oracle Applications UX Chief Evangelist Patanjali Venkatacharya organized and moderated an innovative and stimulating panel discussion titled "What Makes a Good Design Critic? Food Design vs. Product Design Criticism" at CHI 2010, the annual ACM Conference on Human Factors in Computing Systems. The panelists included Janice Rohn, VP of User Experience at Experian; Tami Hardeman, a food stylist; Ed Seiber, a restaurant architect and designer; Jonathan Kessler, a food critic and writer at the Atlanta Journal-Constitution; and Larry Powers, Chef de Cuisine at Shaun's restaurant in Atlanta, Georgia. Building off the momentum of his highly acclaimed panel at CHI 2009 on what interaction design can learn from food design (for which I was on the other side as a panelist), Venkatacharya brought together new people with different roles in the restaurant and software interaction design fields. The session was also quite delicious -- but more on that later. Criticism, as it applies to food and product or interaction design, was the tasty topic for this forum and showed that strong parallels exist between food and interaction design criticism. Figure 1. The panelists in discussion: (left to right) Janice Rohn, Ed Seiber, Tami Hardeman, and Jonathan Kessler. The panelists had great insights to share from their respective fields, and they enthusiastically discussed as if they were at a casual collegial dinner. Jonathan Kessler stated that he prefers to have one professional critic's opinion in general than a large sampling of customers, however, "Web sites like Yelp get users excited by the collective approach. People are attracted to things desired by so many." Janice Rohn added that this collective desire was especially true for users of consumer products. Ed Seiber remarked that while people looked to the popular view for their target tastes and product choices, "professional critics like John [Kessler] still hold a big weight on public opinion." Chef Powers indicated that chefs take in feedback from all sources, adding, "word of mouth is very powerful. We also look heavily at the sales of the dishes to see what's moving; what's selling and thus successful." Hearing this discussion validates our design work at Oracle in that we listen to our users (our diners) and industry feedback (our critics) to ensure an optimal user experience of our products. Rohn considers that restaurateur Danny Meyer's book, Setting the Table: The Transforming Power of Hospitality in Business, which is about creating successful restaurant experiences, has many applicable parallels to user experience design. Meyer actually argues that the customer is not always right, but that "they must always feel heard." Seiber agreed, but noted "customers are not designers," and while designers need to listen to customer feedback, it is the designer's job to synthesize it. Seiber feels it's the critic's job to point out when something is missing or not well-prioritized. In interaction design, our challenges are quite similar, if not parallel. Software tasks are like puzzles that are in search of a solution on how to be best completed. As a food stylist, Tami Hardeman has the demanding and challenging task of presenting food to be as delectable as can be. To present food in its best light requires a lot of creativity and insight into consumer tastes. It's no doubt then that this former fashion stylist came up with the ultimate catch phrase to capture the emotion that clients want to draw from their users: "craveability." The phrase was a hit with the audience and panelists alike. Sometime later in the discussion, Seiber remarked, "designers strive to apply craveability to products, and I do so for restaurants in my case." Craveabilty is also very applicable to interaction design. Creating straightforward and smooth workflows for users of Oracle Applications is a primary goal for my colleagues. We want our users to really enjoy working with our products where it makes them more efficient and better at their jobs. That's our "craveability." Patanjali Venkatacharya asked the panel, "if a design's "craveability" appeals to some cultures but not to others, then what is the impact to the food or product design process?" Rohn stated that "taste is part nature and part nurture" and that the design must take the full context of a product's usage into consideration. Kessler added, "good design is about understanding the context" that the experience necessitates. Seiber remarked how important seat comfort is for diners and how the quality of seating will add so much to the complete dining experience. Sometimes if these non-food factors are not well executed, they can also take away from an otherwise pleasant dining experience. Kessler recounted a time when he was dining at a restaurant that actually had very good food, but the photographs hanging on all the walls did not fit in with the overall décor and created a negative overall dining experience. While the tastiness of the food is critical to a restaurant's success, it is a captivating complete user experience, as in interaction design, which will keep customers coming back and ultimately making the restaurant a hit. Figure 2. Patnajali Venkatacharya enjoyed the Sardian flatbread salad. As a surprise Chef Powers brought out a signature dish from Shaun's restaurant for all the panelists to sample and critique. The Sardinian flatbread dish showcased Atlanta's taste for fresh and local produce and cheese at its finest as a salad served on a crispy flavorful flat bread. Hardeman said it could be photographed from any angle, a high compliment coming from a food stylist. Seiber really enjoyed the colors that the dish brought together and thought it would be served very well in a casual restaurant on a summer's day. The panel really appreciated the taste and quality of the different components and how the rosemary brought all the flavors together. Seiber remarked that "a lot of effort goes into the appearance of simplicity." Rohn indicated that the same notion holds true with software user interface design. A tremendous amount of work goes into crafting straightforward interfaces, including user research, prototyping, design iterations, and usability studies. Design criticism for food and software interfaces clearly share many similarities. Both areas value expert opinions and user feedback. Both areas understand the importance of great design needing to work well in its context. Last but not least, both food and interaction design criticism value "craveability" and how having users excited about experiencing and enjoying the designs is an important goal. Now if we can just improve the taste of software user interfaces, people may choose to dine on their enterprise applications over a fresh organic salad.

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• How accurate is "Business logic should be in a service, not in a model"?

  - by Jeroen Vannevel

  Situation Earlier this evening I gave an answer to a question on StackOverflow. The question: Editing of an existing object should be done in repository layer or in service? For example if I have a User that has debt. I want to change his debt. Should I do it in UserRepository or in service for example BuyingService by getting an object, editing it and saving it ? My answer: You should leave the responsibility of mutating an object to that same object and use the repository to retrieve this object. Example situation: class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } A comment I received: Business logic should really be in a service. Not in a model. What does the internet say? So, this got me searching since I've never really (consciously) used a service layer. I started reading up on the Service Layer pattern and the Unit Of Work pattern but so far I can't say I'm convinced a service layer has to be used. Take for example this article by Martin Fowler on the anti-pattern of an Anemic Domain Model: There are objects, many named after the nouns in the domain space, and these objects are connected with the rich relationships and structure that true domain models have. The catch comes when you look at the behavior, and you realize that there is hardly any behavior on these objects, making them little more than bags of getters and setters. Indeed often these models come with design rules that say that you are not to put any domain logic in the the domain objects. Instead there are a set of service objects which capture all the domain logic. These services live on top of the domain model and use the domain model for data. (...) The logic that should be in a domain object is domain logic - validations, calculations, business rules - whatever you like to call it. To me, this seemed exactly what the situation was about: I advocated the manipulation of an object's data by introducing methods inside that class that do just that. However I realize that this should be a given either way, and it probably has more to do with how these methods are invoked (using a repository). I also had the feeling that in that article (see below), a Service Layer is more considered as a façade that delegates work to the underlying model, than an actual work-intensive layer. Application Layer [his name for Service Layer]: Defines the jobs the software is supposed to do and directs the expressive domain objects to work out problems. The tasks this layer is responsible for are meaningful to the business or necessary for interaction with the application layers of other systems. This layer is kept thin. It does not contain business rules or knowledge, but only coordinates tasks and delegates work to collaborations of domain objects in the next layer down. It does not have state reflecting the business situation, but it can have state that reflects the progress of a task for the user or the program. Which is reinforced here: Service interfaces. Services expose a service interface to which all inbound messages are sent. You can think of a service interface as a façade that exposes the business logic implemented in the application (typically, logic in the business layer) to potential consumers. And here: The service layer should be devoid of any application or business logic and should focus primarily on a few concerns. It should wrap Business Layer calls, translate your Domain in a common language that your clients can understand, and handle the communication medium between server and requesting client. This is a serious contrast to other resources that talk about the Service Layer: The service layer should consist of classes with methods that are units of work with actions that belong in the same transaction. Or the second answer to a question I've already linked: At some point, your application will want some business logic. Also, you might want to validate the input to make sure that there isn't something evil or nonperforming being requested. This logic belongs in your service layer. "Solution"? Following the guidelines in this answer, I came up with the following approach that uses a Service Layer: class UserController : Controller { private UserService _userService; public UserController(UserService userService){ _userService = userService; } public ActionResult MakeHimPay(string username, int amount) { _userService.MakeHimPay(username, amount); return RedirectToAction("ShowUserOverview"); } public ActionResult ShowUserOverview() { return View(); } } class UserService { private IUserRepository _userRepository; public UserService(IUserRepository userRepository) { _userRepository = userRepository; } public void MakeHimPay(username, amount) { _userRepository.GetUserByName(username).makePayment(amount); } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } Conclusion All together not much has changed here: code from the controller has moved to the service layer (which is a good thing, so there is an upside to this approach). However this doesn't look like it had anything to do with my original answer. I realize design patterns are guidelines, not rules set in stone to be implemented whenever possible. Yet I have not found a definitive explanation of the service layer and how it should be regarded. Is it a means to simply extract logic from the controller and put it inside a service instead? Is it supposed to form a contract between the controller and the domain? Should there be a layer between the domain and the service layer? And, last but not least: following the original comment Business logic should really be in a service. Not in a model. Is this correct? How would I introduce my business logic in a service instead of the model?

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• Big Visible Charts

  - by Robert May

  An important part of Agile is the concept of transparency and visibility. In proper functioning teams, stakeholders can look at any team at any time in the iteration or release and see how that team is doing by simply looking at what we call Big Visible Charts. If you’ve done Scrum, you’ve seen these charts. However, interpreting these charts can often be an art form. There are several different charts that can be useful. In this newsletter, I’ll focus on the Iteration Burndown and Cumulative Flow charts. I’ve included a copy of the spreadsheet that I used to create the charts, and if you don’t have a tool that creates them for you, you can use this spreadsheet to do so. Our preferred tool for managing Scrum projects is Rally. Rally creates all of these charts for you, saving you quite a bit of time. The Iteration Burndown and Cumulative Flow Charts This is the main chart that teams use. Although less useful to stakeholders, this chart is critical to the team and provides quite a bit of information to the team about how their iteration is going. Most charts are a combination of the charts below, so you may need to combine aspects of each section to understand what is happening in your iterations. Ideal Ah, isn’t that a pretty picture? Unfortunately, it’s also very unrealistic. I’ve seen iterations that come close to ideal, but never that match perfectly. If your iteration matches perfectly, chances are, someone is playing with the numbers. Reality is just too difficult to have a burndown chart that matches this exactly. Late Planning Iteration started, but the team didn’t. You can tell this by the fact that the real number of estimated hours didn’t appear until day two. In the cumulative flow, you can also see that nothing was defined in Day one and two. You want to avoid situations like this. You’ll note that the team had to burn faster than is ideal to meet the iteration because of the late planning. This often results in long weeks and days. Testing Starved Determining whether or not testing is starved is difficult without the cumulative flow. The pattern in the burndown could be nothing more that developers not completing stories early enough or could be caused by stories being too big. With the cumulative flow, however, you see that only small bites are in progress and stories were completed early, but testing didn’t start testing until the end of the iteration, and didn’t complete testing all stories in the iteration. When this happens, question whether or not your testing resources are sufficient for your team and whether or not acceptance is adequately defined. No Testing With this one, both graphs show the same thing; the team needs testers and testing! Without testing, what was completed cannot be verified to make sure that it is acceptable to the business. If you find yourself in this situation, review your testing practices and acceptance testing process and make changes today. Late Development With this situation, both graphs tell a story. In the top graph, you can see that the hours failed to burn down as quickly as the team expected. This could be caused by the team not correctly estimating their hours or the team could have had illness or some other issue that affected them. Often, when teams are tackling something that is more unknown, they’ll run into technical barriers that cause the burn down to happen slower than expected. In the cumulative flow graph, you can see that not much was completed in the first few days. This could be because of illness or technical barriers or simply poor estimation. Testing was able to keep up with everything that was completed, however. No Tool Updating When you see graphs that look like this, you can be assured that it’s because the team is not updating the tool that generates the graphs. Review your policy for when they are to update. On the teams that I run, I require that each team member updates the tool at least once daily. You should also check to see how well the team is breaking down stories into tasks. If they’re creating few large tasks, graphs can look similar to this. As a general rule, I never allow tasks, other than Unit Testing and Uncertainty, to be greater than eight hours in duration. Scope Increase I always encourage team members to enter in however much time they think they have left on a task, even if that means increasing the total amount of time left to do. You get a much better and more realistic picture this way. Increasing time remaining could explain the burndown graph, but by looking at the cumulative flow graph, we can see that stories were added to the iteration and scope was increased. Since planning should consume all of the hours in the iteration, this is almost always a bad thing. If the scope change happened late in the iteration and the hours remaining were well below the ideal burn, then increasing scope is probably o.k., but estimation needs to get better. However, with the charts above, that’s clearly not what happened and the team was required to do extra work to make the iteration. If you find this happening, your product owner and ScrumMasters need training. The team also needs to learn to say no. Scope Decrease Scope decreases are just as bad as scope increases. Usually, graphs above show that the team did a poor job of estimating their stories and part way through had to reduce scope to change the iteration. This will happen once in a while, but if you find it’s a pattern on your team, you need to re-evaluate planning. Some teams are hopelessly optimistic. In those cases, I’ll introduce a task I call “Uncertainty.” With Uncertainty, the team estimates how many hours they might need if things don’t go well with the tasks they’ve defined. They try to estimate things that could go poorly and increase the time appropriately. Having an Uncertainty task allows them to have a low and high estimate. Uncertainty should not just be an arbitrary buffer. It must correlate to real uncertainty in the tasks that have been defined. Stories are too Big Often, we see graphs like the ones above. Note that the burndown looks fairly good, other than the chunky acceptance of stories. However, when you look at cumulative flow, you can see that at one point, everything is in progress. This is a bad thing. When you see graphs like this, you’re in one of two states. You may just have a very small team and can only handle one or two stories in your iteration. If you have more than one or two people, then the most likely problem is that your stories are far too big. To combat this, break large high hour stories into smaller pieces that can be completed independently and accepted independently. If you don’t, you’ll likely be requiring your testers to do heroic things to complete testing on the last day of the iteration and you’re much more likely to have the entire iteration fail, because of the limited amount of things that can be completed. Summary There are other charts that can be useful when doing scrum. If you don’t have any big visible charts, you really need to evaluate your process and change. These charts can provide the team a wealth of information and help you write better software. If you have any questions about charts that you’re seeing on your team, contact me with a screen capture of the charts and I’ll tell you what I’m seeing in those charts. I always want this information to be useful, so please let me know if you have other questions. Technorati Tags: Agile

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• Master Data

  - by david.butler(at)oracle.com

  Let's take a deeper look at what we mean when we talk about 'Master' data. In its most general sense, master data is data that exists in more than one operational application. These are the applications that automate business processes. These applications require significant amounts of data to function correctly.  This includes data about the objects that are involved in transactions, as well as the transaction data itself.  For example, when a customer buys a product, the transaction is managed by a sales application.  The objects of the transaction are the Customer and the Product.  The transactional data is the time, place, price, discount, payment methods, etc. used at the point of sale. Many thousands of transactional data attributes are needed within the application. These important data elements are local to the applications and have no bearing on other applications. Harmonization and synchronization across applications is not necessary. The Customer and Product objects of the transaction also have a large number of attributes. Customer for example, includes hierarchies, hierarchical and matrixed relationships, contacts, classifications, preferences, accounts, identifiers, profiles, and addresses galore for 'ship to', 'mail to'; 'service at'; etc. Dozens of attributes exist for individuals, hundreds for organizations, and thousands for products. This data has meaning beyond any particular application. It exists in many applications and drives the vital cross application enterprise business processes. These are the processes that define and differentiate the organization. At every decision point, information about the objects of the process determines the direction of the process flow. This is the nature of the data that exists in more than one application, and this is why we call it 'master data'. Let me elaborate. Parties Oracle has developed a party schema to model all participants in your daily business operations. It models people, organizations, groups, customers, contacts, employees, and suppliers. It models their accounts, locations, classifications, and preferences.  And most importantly, it models the vast array of hierarchical and matrixed relationships that exist between all the participants in your real world operations.  The model logically separates people and organizations from their relationships and accounts.  This separation creates flexibility unmatched in the industry and accounts for the fact that the Oracle schema for Customers, Suppliers, and Accounts is a true superset of the wide variety of commercial and homegrown customer models in existence. Sites Sites are places where business is conducted. They can be addresses, clusters such as retail malls, locations within a cluster, floors within a building, places where meters are located, rooms on floors, etc.  Fully understanding all attributes of a site is key to many business processes. Attributes such as 'noise abatement policy' at a point of delivery, or the size of an oven in a business kitchen drive day-to-day activities such as delivery schedules or food promotions. Typically this kind of data is siloed in departments and scattered across applications and spreadsheets.  This leads to conflicting information and poor operational efficiencies. Oracle's Global Single Schema can hold all site attributes in one place and enables a single version of authoritative site information across the enterprise. Products and Services The Oracle Global Single Schema also includes a number of entities that define the products and services a company creates and offers for sale. Key entities include Items organized into Catalogs and Price Lists. The Catalog structures provide for the ability to capture different views of a product such as engineering, manufacturing, and service which are based on a unified product model. As a result, designers, manufacturing engineers, purchasers and partners can work simultaneously on a common product definition. The Catalog schema allows for unlimited attributes, combines them into meaningful groups, and maps them to catalog categories to track these different types of information. The model also maps an unlimited number of functional structures for each item. For example, multiple Bills of Material (BOMs) can be constructed representing requirements BOM, features BOM, and packaging BOM for an item. The Catalog model also supports hierarchical information about each item and all standard Global Data Synchronization attributes. Business Processes Utilizing Linked Data Entities Each business entity codified into a centralized master data environment significantly improves the efficiency of the automated business processes that use the consolidated data.  When all the key business entities used by an organization's process are so consolidated, the advantages are multiplied.  The primary reason for business process breakdowns (i.e. data errors across application boundaries) is eliminated. All processes are positively impacted and business process automation is itself automated.  I like to use the "Call to Resolution" business process as an example to help illustrate this important point. It involves call center applications, service applications, RMA applications, transportation applications, inventory applications, etc. Customer, Site, Product and Supplier master data must all be correct and consistent across these applications.  What's more, the data relationships between customer and product, and product and suppliers must be right. This is the minimum quality needed to insure the business process flows without error. But that is not the end of the story. Critical master data attributes such as customer loyalty, profitability, credit worthiness, and propensity to buy can optimize the call center point of contact component of the process. Critical product information such as alternative parts or equivalent products can optimize the resolution selected by the process. A comprehensive understanding of the 'service at' location can help insure multiple trips are avoided in the process. Full supplier information on reliability, delivery delays, and potential alternates can prevent supplier exceptions and play a significant role in optimizing the process.  In other words, these master data attributes enable the optimization of the "Call to Resolution" enterprise business process. Master data supports and guides business process flows. Thus the phrase 'Master Data' is indeed appropriate. MDM is the software that houses, manages, and governs the master data that resides in all applications and controls the enterprise business processes. A complete master data solution takes a data model that holds fully attributed master data entities and their inter-relationships. Oracle has this model. Oracle, with its deep understanding of application data is the logical choice for managing all your master data within the enterprise whether or not your organization actually runs any Oracle Applications.

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• DRY and SRP

  - by Timothy Klenke

  Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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• How do I restrict concurrent statistics gathering to a small set of tables from a single schema?

  - by Maria Colgan

  I got an interesting question from one of my colleagues in the performance team last week about how to restrict a concurrent statistics gather to a small subset of tables from one schema, rather than the entire schema. I thought I would share the solution we came up with because it was rather elegant, and took advantage of concurrent statistics gathering, incremental statistics, and the not so well known “obj_filter_list” parameter in DBMS_STATS.GATHER_SCHEMA_STATS procedure. You should note that the solution outline below with “obj_filter_list” still applies, even when concurrent statistics gathering and/or incremental statistics gathering is disabled. The reason my colleague had asked the question in the first place was because he wanted to enable incremental statistics for 5 large partitioned tables in one schema. The first time you gather statistics after you enable incremental statistics on a table, you have to gather statistics for all of the existing partitions so that a synopsis may be created for them. If the partitioned table in question is large and contains a lot of partition, this could take a considerable amount of time. Since my colleague only had the Exadata environment at his disposal overnight, he wanted to re-gather statistics on 5 partition tables as quickly as possible to ensure that it all finished before morning. Prior to Oracle Database 11g Release 2, the only way to do this would have been to write a script with an individual DBMS_STATS.GATHER_TABLE_STATS command for each partition, in each of the 5 tables, as well as another one to gather global statistics on the table. Then, run each script in a separate session and manually manage how many of this session could run concurrently. Since each table has over one thousand partitions that would definitely be a daunting task and would most likely keep my colleague up all night! In Oracle Database 11g Release 2 we can take advantage of concurrent statistics gathering, which enables us to gather statistics on multiple tables in a schema (or database), and multiple (sub)partitions within a table concurrently. By using concurrent statistics gathering we no longer have to run individual statistics gathering commands for each partition. Oracle will automatically create a statistics gathering job for each partition, and one for the global statistics on each partitioned table. With the use of concurrent statistics, our script can now be simplified to just five DBMS_STATS.GATHER_TABLE_STATS commands, one for each table. This approach would work just fine but we really wanted to get this down to just one command. So how can we do that? You may be wondering why we didn’t just use the DBMS_STATS.GATHER_SCHEMA_STATS procedure with the OPTION parameter set to ‘GATHER STALE’. Unfortunately the statistics on the 5 partitioned tables were not stale and enabling incremental statistics does not mark the existing statistics stale. Plus how would we limit the schema statistics gather to just the 5 partitioned tables? So we went to ask one of the statistics developers if there was an alternative way. The developer told us the advantage of the “obj_filter_list” parameter in DBMS_STATS.GATHER_SCHEMA_STATS procedure. The “obj_filter_list” parameter allows you to specify a list of objects that you want to gather statistics on within a schema or database. The parameter takes a collection of type DBMS_STATS.OBJECTTAB. Each entry in the collection has 5 feilds; the schema name or the object owner, the object type (i.e., ‘TABLE’ or ‘INDEX’), object name, partition name, and subpartition name. You don't have to specify all five fields for each entry. Empty fields in an entry are treated as if it is a wildcard field (similar to ‘*’ character in LIKE predicates). Each entry corresponds to one set of filter conditions on the objects. If you have more than one entry, an object is qualified for statistics gathering as long as it satisfies the filter conditions in one entry. You first must create the collection of objects, and then gather statistics for the specified collection. It’s probably easier to explain this with an example. I’m using the SH sample schema but needed a couple of additional partitioned table tables to get recreate my colleagues scenario of 5 partitioned tables. So I created SALES2, SALES3, and COSTS2 as copies of the SALES and COSTS table respectively (setup.sql). I also deleted statistics on all of the tables in the SH schema beforehand to more easily demonstrate our approach. Step 0. Delete the statistics on the tables in the SH schema. Step 1. Enable concurrent statistics gathering. Remember, this has to be done at the global level. Step 2. Enable incremental statistics for the 5 partitioned tables. Step 3. Create the DBMS_STATS.OBJECTTAB and pass it to the DBMS_STATS.GATHER_SCHEMA_STATS command. Here, you will notice that we defined two variables of DBMS_STATS.OBJECTTAB type. The first, filter_lst, will be used to pass the list of tables we want to gather statistics on, and will be the value passed to the obj_filter_list parameter. The second, obj_lst, will be used to capture the list of tables that have had statistics gathered on them by this command, and will be the value passed to the objlist parameter. In Oracle Database 11g Release 2, you need to specify the objlist parameter in order to get the obj_filter_list parameter to work correctly due to bug 14539274. Will also needed to define the number of objects we would supply in the obj_filter_list. In our case we ere specifying 5 tables (filter_lst.extend(5)). Finally, we need to specify the owner name and object name for each of the objects in the list. Once the list definition is complete we can issue the DBMS_STATS.GATHER_SCHEMA_STATS command. Step 4. Confirm statistics were gathered on the 5 partitioned tables. Here are a couple of other things to keep in mind when specifying the entries for the  obj_filter_list parameter. If a field in the entry is empty, i.e., null, it means there is no condition on this field. In the above example , suppose you remove the statement Obj_filter_lst(1).ownname := ‘SH’; You will get the same result since when you have specified gather_schema_stats so there is no need to further specify ownname in the obj_filter_lst. All of the names in the entry are normalized, i.e., uppercased if they are not double quoted. So in the above example, it is OK to use Obj_filter_lst(1).objname := ‘sales’;. However if you have a table called ‘MyTab’ instead of ‘MYTAB’, then you need to specify Obj_filter_lst(1).objname := ‘”MyTab”’; As I said before, although we have illustrated the usage of the obj_filter_list parameter for partitioned tables, with concurrent and incremental statistics gathering turned on, the obj_filter_list parameter is generally applicable to any gather_database_stats, gather_dictionary_stats and gather_schema_stats command. You can get a copy of the script I used to generate this post here. +Maria Colgan

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• Microphone not capturing sound on 12.04 Lenovo G580

  - by Yam Marcovic

  In both Skype and the Sound Recorder application, I am not capturing any audio from my built-in microphone. I'm not sure why. Otherwise, sound output is working well. I have tried running gstreamer-properties and setting the Default Input plugin to PulseAUdio as well (to match the output), and it didn't help. I have tried running alsamixer -V all and I only get 2 input-related entries: Capture(L R) which is on 100 and not muted (can't be either), and Analog Mic Boost which is on 20db. Extra info: Camera (video) is working well on Skype and Kamerka. Can you please help me get my microphone to work? lspci: 00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx- Latency: 0 Capabilities: <access denied> Kernel driver in use: agpgart-intel 00:02.0 VGA compatible controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09) (prog-if 00 [VGA controller]) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 42 Region 0: Memory at e0000000 (64-bit, non-prefetchable) [size=4M] Region 2: Memory at d0000000 (64-bit, prefetchable) [size=256M] Region 4: I/O ports at 3000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities: <access denied> Kernel driver in use: i915 Kernel modules: i915 00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04) (prog-if 30 [XHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 41 Region 0: Memory at e0600000 (64-bit, non-prefetchable) [size=64K] Capabilities: <access denied> Kernel driver in use: xhci_hcd 00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 43 Region 0: Memory at e0614000 (64-bit, non-prefetchable) [size=16] Capabilities: <access denied> Kernel driver in use: mei Kernel modules: mei 00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04) (prog-if 20 [EHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 16 Region 0: Memory at e0619000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 44 Region 0: Memory at e0610000 (64-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: snd_hda_intel Kernel modules: snd-hda-intel 00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Bus: primary=00, secondary=01, subordinate=01, sec-latency=0 I/O behind bridge: 00002000-00002fff Memory behind bridge: e0500000-e05fffff Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Bus: primary=00, secondary=02, subordinate=02, sec-latency=0 Memory behind bridge: e0400000-e04fffff Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: <access denied> Kernel driver in use: pcieport Kernel modules: shpchp 00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) (prog-if 20 [EHCI]) Subsystem: Lenovo Device 3977 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 23 Region 0: Memory at e0618000 (32-bit, non-prefetchable) [size=1K] Capabilities: <access denied> Kernel driver in use: ehci_hcd 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Capabilities: <access denied> Kernel modules: iTCO_wdt 00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04) (prog-if 01 [AHCI 1.0]) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin B routed to IRQ 40 Region 0: I/O ports at 3088 [size=8] Region 1: I/O ports at 3094 [size=4] Region 2: I/O ports at 3080 [size=8] Region 3: I/O ports at 3090 [size=4] Region 4: I/O ports at 3060 [size=32] Region 5: Memory at e0617000 (32-bit, non-prefetchable) [size=2K] Capabilities: <access denied> Kernel driver in use: ahci 00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04) Subsystem: Lenovo Device 3977 Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin C routed to IRQ 10 Region 0: Memory at e0615000 (64-bit, non-prefetchable) [size=256] Region 4: I/O ports at 3040 [size=32] Kernel modules: i2c-i801 01:00.0 Ethernet controller: Atheros Communications Inc. AR8162 Fast Ethernet (rev 08) Subsystem: Lenovo Device 3979 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 11 Region 0: Memory at e0500000 (64-bit, non-prefetchable) [size=256K] Region 2: I/O ports at 2000 [size=128] Capabilities: <access denied> 02:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01) Subsystem: Lenovo Device 31a1 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 17 Region 0: Memory at e0400000 (64-bit, non-prefetchable) [size=64K] Capabilities: <access denied> Kernel driver in use: ath9k Kernel modules: ath9k aplay -l **** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: CONEXANT Analog [CONEXANT Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0

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• Refactoring Part 1 : Intuitive Investments

  - by Wes McClure

  Fear, it’s what turns maintaining applications into a nightmare.  Technology moves on, teams move on, someone is left to operate the application, what was green is now perceived brown.  Eventually the business will evolve and changes will need to be made.  The approach to those changes often dictates the long term viability of the application.  Fear of change, lack of passion and a lack of interest in understanding the domain often leads to a paranoia to do anything that doesn’t involve duct tape and bailing twine.  Don’t get me wrong, those have a place in the short term viability of a project but they don’t have a place in the long term.  Add to it “us versus them” in regards to the original team and those that maintain it, internal politics and other factors and you have a recipe for disaster.  This results in code that quickly becomes unmanageable.  Even the most clever of designs will eventually become sub optimal and debt will amount that exponentially makes changes difficult.  This is where refactoring comes in, and it’s something I’m very passionate about.  Refactoring is about improving the process whereby we make change, it’s an exponential investment in the process of change. Without it we will incur exponential complexity that halts productivity. Investments, especially in the long term, require intuition and reflection.  How can we tackle new development effectively via evolving the original design and paying off debt that has been incurred? The longer we wait to ask and answer this question, the more it will cost us.  Small requests don’t warrant big changes, but realizing when changes now will pay off in the long term, and especially in the short term, is valuable. I have done my fair share of maintaining applications and continuously refactoring as needed, but recently I’ve begun work on a project that hasn’t had much debt, if any, paid down in years.  This is the first in a series of blog posts to try to capture the process which is largely driven by intuition of smaller refactorings from other projects. Signs that refactoring could help: Testability How can decreasing test time not pay dividends? One of the first things I found was that a very important piece often takes 30+ minutes to test.  I can only imagine how much time this has cost historically, but more importantly the time it might cost in the coming weeks: I estimate at least 10-20 hours per person!  This is simply unacceptable for almost any situation.  As it turns out, about 6 hours of working with this part of the application and I was able to cut the time down to under 30 seconds!  In less than the lost time of one week, I was able to fix the problem for all future weeks! If we can’t test fast then we can’t change fast, nor with confidence. Code is used by end users and it’s also used by developers, consider your own needs in terms of the code base.  Adding logic to enable/disable features during testing can help decouple parts of an application and lead to massive improvements.  What exactly is so wrong about test code in real code?  Often, these become features for operators and sometimes end users.  If you cannot run an integration test within a test runner in your IDE, it’s time to refactor. Readability Are variables named meaningfully via a ubiquitous language? Is the code segmented functionally or behaviorally so as to minimize the complexity of any one area? Are aspects properly segmented to avoid confusion (security, logging, transactions, translations, dependency management etc) Is the code declarative (what) or imperative (how)?  What matters, not how.  LINQ is a great abstraction of the what, not how, of collection manipulation.  The Reactive framework is a great example of the what, not how, of managing streams of data. Are constants abstracted and named, or are they just inline? Do people constantly bitch about the code/design? If the code is hard to understand, it will be hard to change with confidence.  It’s a large undertaking if the original designers didn’t pay much attention to readability and as such will never be done to “completion.”  Make sure not to go over board, instead use this as you change an application, not in lieu of changes (like with testability). Complexity Simplicity will never be achieved, it’s highly subjective.  That said, a lot of code can be significantly simplified, tidy it up as you go.  Refactoring will often converge upon a simplification step after enough time, keep an eye out for this. Understandability In the process of changing code, one often gains a better understanding of it.  Refactoring code is a good way to learn how it works.  However, it’s usually best in combination with other reasons, in effect killing two birds with one stone.  Often this is done when readability is poor, in which case understandability is usually poor as well.  In the large undertaking we are making with this legacy application, we will be replacing it.  Therefore, understanding all of its features is important and this refactoring technique will come in very handy. Unused code How can deleting things not help? This is a freebie in refactoring, it’s very easy to detect with modern tools, especially in statically typed languages.  We have VCS for a reason, if in doubt, delete it out (ok that was cheesy)! If you don’t know where to start when refactoring, this is an excellent starting point! Duplication Do not pray and sacrifice to the anti-duplication gods, there are excellent examples where consolidated code is a horrible idea, usually with divergent domains.  That said, mediocre developers live by copy/paste.  Other times features converge and aren’t combined.  Tools for finding similar code are great in the example of copy/paste problems.  Knowledge of the domain helps identify convergent concepts that often lead to convergent solutions and will give intuition for where to look for conceptual repetition. 80/20 and the Boy Scouts It’s often said that 80% of the time 20% of the application is used most.  These tend to be the parts that are changed.  There are also parts of the code where 80% of the time is spent changing 20% (probably for all the refactoring smells above).  I focus on these areas any time I make a change and follow the philosophy of the Boy Scout in cleaning up more than I messed up.  If I spend 2 hours changing an application, in the 20%, I’ll always spend at least 15 minutes cleaning it or nearby areas. This gives a huge productivity edge on developers that don’t. Ironically after a short period of time the 20% shrinks enough that we don’t have to spend 80% of our time there and can move on to other areas.   Refactoring is highly subjective, never attempt to refactor to completion!  Learn to be comfortable with leaving one part of the application in a better state than others.  It’s an evolution, not a revolution.  These are some simple areas to look into when making changes and can help get one started in the process.  I’ve often found that refactoring is a convergent process towards simplicity that sometimes spans a few hours but often can lead to massive simplifications over the timespan of weeks and months of regular development.

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• Learnings from trying to write better software: Loud errors from the very start

  - by theo.spears

  Microsoft made a very small number of backwards incompatible changes between .NET 1.1 and 2.0, because they wanted to make it as easy and safe as possible to port applications to the new runtime. (Here’s a list.) However, one thing they did change was what happens when a background thread fails with an unhanded exception - in .NET 1.1 nothing happened, the thread terminated, and the application continued oblivious. Try the same trick in .NET 2.0 and the entire application, including all threads, will rudely terminate. There are three reasons for this. Firstly if a background thread has crashed, it may have left the entire application in an inconsistent state, in a way that will affect other threads. It’s better to terminate the entire application than continue and have the application perform actions based on a broken state, for example take customer orders, or write corrupt files to disk.  Secondly, during software development, it is far better for errors to be loud and obtrusive. Even if you have unit tests and integration tests (and you should), a key part of ensuring software works properly is to actually try using it, both through systematic testing and through the casual use all software gets by its developers during use. Subtle errors are easy to miss if you are not actually doing real work using the application, loud errors are obvious. Thirdly, and most importantly, even if catching and swallowing exceptions indiscriminately doesn't cause any problems in your application, the presence of unexpected exceptions shows you do not fully understand the behavior of your code. The currently released version of your application may be absolutely correct. However, because your mental model of the behavior is wrong, any future change you make to the program could and probably will introduce critical errors.  This applies to more than just exceptions causing threads to exit, any unexpected state should make the application blow up in an un-ignorable way. The worst thing you can do is silently swallow errors and continue. And let's be clear, writing to a log file does not count as blowing up in an un-ignorable way.  This is all simple as long as the call stack only contains your code, but when your functions start to be called by third party or .NET framework code, it's surprisingly easy for exceptions to start vanishing. Let's look at two examples.   1. Windows forms drag drop events  Usually if you throw an exception from a winforms event handler it will bring up the "application has crashed" dialog with abort and continue options. This is a good default behavior - the error is big and loud, but it is possible for the user to ignore the error and hopefully save their data, if somehow this bug makes it past testing. However drag and drop are different - throw an exception from one of these and it will just be silently swallowed with no explanation.  By the way, it's not just drag and drop events. Timer events do it too.  You can research how exceptions are treated in different handlers and code appropriately, but the safest and most user friendly approach is to always catch exceptions in your event handlers and show your own error message. I'll talk about one good approach to handling these exceptions at the end of this post.   2. SSMS integration for SQL Tab Magic  A while back wrote an SSMS add-in called SQL Tab Magic (learn more about the process here). It works by listening to certain SSMS events and remembering what documents are opened and closed. I deployed it internally and it was used for a few months by a number of people without problems, so I was reasonably confident in its quality. Before releasing I made a few cleanups, including introducing error reporting. Bam. A few days later I was looking at over 1,000 error reports in my inbox. In turns out I wasn't handling table designers properly. The exceptions were there, but again SSMS was helpfully swallowing them all for me, so I was blissfully unaware. Had I made my errors loud from the start, I would have noticed these issues long before and fixed them.   Handling exceptions  Now you are systematically catching exceptions throughout your application, you need to do something with them. I've tried 3 options: log them, alert the user, and automatically send them home.  There are a few good options for logging in .NET. The most widespread is Apache log4net, which provides a very capable and configurable logging framework. There is also NLog which has a compatible interface, with a greater emphasis on fluent rather than XML configuration.  Alerting the user serves two purposes. Firstly it means they understand their action has failed to they don't just assume it worked (Silent file copy failure is a problem if you then delete the originals) or that they should keep waiting for a background task to complete. Secondly, it means the users can report the bug to your support team, and then you can fix it. This means the message you show the user should contain the information you need as a developer to identify and fix it. And the user will probably just send you a screenshot of the dialog, so it shouldn't be hidden by scroll bars.  This leads us to the third option, automatically sending error reports home. By automatic I mean with minimal effort on the part of the user, rather than doing it silently behind their backs. The advantage of this is you can send back far more detailed and precise information than you can expect a user to include in an email, and by making it easier to report errors, you make it more likely users will do so.  We do this using a great tool called SmartAssembly (full disclosure: this is a product made by Red Gate). It captures complete stack traces including the values of all local variables and then allows the user to send all this information back with a single click. We also capture log files to help understand what lead up to the error. We then use the free SmartAssembly Sync for Jira to dedupe these reports and raise them as bugs in our bug tracking system.  The combined effect of loud errors during development and then automatic error reporting once software is deployed allows us to find and fix more bugs, correct misunderstandings on how our software works, and overall is a key piece in delivering higher quality software. However it is no substitute for having motivated cunning testers in the building - and we're looking to hire more of those too.   If you found this post interesting you should follow me on twitter.  

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• Passing a parameter so that it cannot be changed – C#

  - by nmarun

  I read this requirement of not allowing a user to change the value of a property passed as a parameter to a method. In C++, as far as I could recall (it’s been over 10 yrs, so I had to refresh memory), you can pass ‘const’ to a function parameter and this ensures that the parameter cannot be changed inside the scope of the function. There’s no such direct way of doing this in C#, but that does not mean it cannot be done!! Ok, so this ‘not-so-direct’ technique depends on the type of the parameter – a simple property or a collection. Parameter as a simple property: This is quite easy (and you might have guessed it already). Bulent Ozkir clearly explains how this can be done here. Parameter as a collection property: Obviously the above does not work if the parameter is a collection of some type. Let’s dig-in. Suppose I need to create a collection of type KeyTitle as defined below. 1: public class KeyTitle 2: { 3: public int Key { get; set; } 4: public string Title { get; set; } 5: } My class is declared as below: 1: public class Class1 2: { 3: public Class1() 4: { 5: MyKeyTitleList = new List<KeyTitle>(); 6: } 7: 8: public List<KeyTitle> MyKeyTitleList { get; set; } 9: public ReadOnlyCollection<KeyTitle> ReadonlyKeyTitleCollection 10: { 11: // .AsReadOnly creates a ReadOnlyCollection<> type 12: get { return MyKeyTitleList.AsReadOnly(); } 13: } 14: } See the .AsReadOnly() method used in the second property? As MSDN says it: “Returns a read-only IList<T> wrapper for the current collection.” Knowing this, I can implement my code as: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8:  9: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 10:  11: Console.ReadLine(); 12: } 13:  14: private static void TryToModifyCollection(ReadOnlyCollection<KeyTitle> readOnlyCollection) 15: { 16: // can only read 17: for (int i = 0; i < readOnlyCollection.Count; i++) 18: { 19: Console.WriteLine("{0} - {1}", readOnlyCollection[i].Key, readOnlyCollection[i].Title); 20: } 21: // Add() - not allowed 22: // even the indexer does not have a setter 23: } The output is as expected: The below image shows two things. In the first line, I’ve tried to access an element in my read-only collection through an indexer. It shows that the ReadOnlyCollection<> does not have a setter on the indexer. The second line tells that there’s no ‘Add()’ method for this type of collection. The capture below shows there’s no ‘Remove()’ method either, there-by eliminating all ways of modifying a collection. Mission accomplished… right? Now, even if you have a collection of different type, all you need to do is to somehow cast (used loosely) it to a List<> and then do a .AsReadOnly() to get a ReadOnlyCollection of your custom collection type. As an example, if you have an IDictionary<int, string>, you can create a List<T> of this type with a wrapper class (KeyTitle in our case). 1: public IDictionary<int, string> MyDictionary { get; set; } 2:  3: public ReadOnlyCollection<KeyTitle> ReadonlyDictionary 4: { 5: get 6: { 7: return (from item in MyDictionary 8: select new KeyTitle 9: { 10: Key = item.Key, 11: Title = item.Value, 12: }).ToList().AsReadOnly(); 13: } 14: } Cool huh? Just one thing you need to know about the .AsReadOnly() method is that the only way to modify your ReadOnlyCollection<> is to modify the original collection. So doing: 1: public static void Main() 2: { 3: Class1 class1 = new Class1(); 4: class1.MyKeyTitleList.Add(new KeyTitle { Key = 1, Title = "abc" }); 5: class1.MyKeyTitleList.Add(new KeyTitle { Key = 2, Title = "def" }); 6: class1.MyKeyTitleList.Add(new KeyTitle { Key = 3, Title = "ghi" }); 7: class1.MyKeyTitleList.Add(new KeyTitle { Key = 4, Title = "jkl" }); 8: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 9:  10: Console.WriteLine(); 11:  12: class1.MyKeyTitleList.Add(new KeyTitle { Key = 5, Title = "mno" }); 13: class1.MyKeyTitleList[2] = new KeyTitle{Key = 3, Title = "GHI"}; 14: TryToModifyCollection(class1.MyKeyTitleList.AsReadOnly()); 15:  16: Console.ReadLine(); 17: } Gives me the output of: See that the second element’s Title is changed to upper-case and the fifth element also gets displayed even though we’re still looping through the same ReadOnlyCollection<KeyTitle>. Verdict: Now you know of a way to implement ‘Method(const param1)’ in your code!

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• Lambda&rsquo;s for .NET made easy&hellip;

  - by mbcrump

  The purpose of my blog is to explain things for a beginner to intermediate c# programmer. I’ve seen several blog post that use lambda expressions always assuming the audience is familiar with them. The purpose of this post is to make them simple and easily understood. Let’s begin with a definition. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. So anonymous function… delegates or expression tree types? I don’t get it??? Confused yet?   Lets break this into a few definitions and jump right into the code. anonymous function – is an "inline" statement or expression that can be used wherever a delegate type is expected. delegate - is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method. The delegate method can be used like any other method, with parameters and a return value. Expression trees - represent code in a tree-like data structure, where each node is an expression, for example, a method call or a binary operation such as x < y.   Don’t worry if this still sounds confusing, lets jump right into the code with a simple 3 line program. We are going to use a Function Delegate (all you need to remember is that this delegate returns a value.) Lambda expressions are used most commonly with the Func and Action delegates, so you will see an example of both of these. Lambda Expression 3 lines. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myfunc = x => x *x;             Console.WriteLine(myfunc(6).ToString());             Console.ReadLine();         }       } } Is equivalent to Old way of doing it. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }            static int myFunc(int x)          {              return x * x;            }       } } In the example, there is a single parameter, x, and the expression is x*x. I’m going to stop here to make sure you are still with me. A lambda expression is an unnamed method written in place of a delegate instance. In other words, the compiler converts the lambda expression to either a : A delegate instance An expression tree All lambda have the following form: (parameters) => expression or statement block Now look back to the ones we have created. It should start to sink in. Don’t get stuck on the => form, use it as an identifier of a lambda. A Lamba expression can also be written in the following form: Lambda Expression. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myFunc = x =>             {                 return x * x;             };               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }       } } This form may be easier to read but consumes more space. Lets try an Action delegate – this delegate does not return a value. Action Delegate example. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Action<string> myAction = (string x) => { Console.WriteLine(x); };             myAction("michael has made this so easy");                                   Console.ReadLine();         }       } } Lambdas can also capture outer variables (such as the example below) A lambda expression can reference the local variables and parameters of the method in which it’s defined. Outer variables referenced by a lambda expression are called captured variables. Capturing Outer Variables using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             string mike = "Michael";             Action<string> myAction = (string x) => {                 Console.WriteLine("{0}{1}", mike, x);          };             myAction(" has made this so easy");                                   Console.ReadLine();         }       } } Lamba’s can also with a strongly typed list to loop through a collection.   Used w a strongly typed list. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             List<string> list = new List<string>() { "1", "2", "3", "4" };             list.ForEach(s => Console.WriteLine(s));             Console.ReadLine();         }       } } Outputs: 1 2 3 4 I think this will get you started with Lambda’s, as always consult the MSDN documentation for more information. Still confused? Hopefully you are not.

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• Delight and Excite

  - by Applications User Experience

  Mick McGee, CEO & President, EchoUser Editor’s Note: EchoUser is a User Experience design firm in San Francisco and a member of the Oracle Usability Advisory Board. Mick and his staff regularly consult on Oracle Applications UX projects. Being part of a user experience design firm, we have the luxury of working with a lot of great people across many great companies. We get to help people solve their problems.  At least we used to. The basic design challenge is still the same; however, the goal is not necessarily to solve “problems” anymore; it is, “I want our products to delight and excite!” The question for us as UX professionals is how to design to those goals, and then how to assess them from a usability perspective. I’m not sure where I first heard “delight and excite” (A book? blog post? Facebook  status? Steve Jobs quote?), but now I hear these listed as user experience goals all the time. In particular, somewhat paradoxically, I routinely hear them in enterprise software conversations. And when asking these same enterprise companies what will make the project successful, we very often hear, “Make it like Apple.” In past days, it was “make it like Yahoo (or Amazon or Google“) but now Apple is the common benchmark. Steve Jobs and Apple were not secrets, but with Jobs’ passing and Apple becoming the world’s most valuable company in the last year, the impact of great design and experience is suddenly very widespread. In particular, users’ expectations have gone way up. Being an enterprise company is no shield to the general expectations that users now have, for all products. Designing a “Minimum Viable Product” The user experience challenge has historically been, to echo the words of Eric Ries (author of Lean Startup) , to create a “minimum viable product”: the proverbial, “make it good enough”. But, in our profession, the “minimum viable” part of that phrase has oftentimes, unfortunately, referred to the design and user experience. Technology typically dominated the focus of the biggest, most successful companies. Few have had the laser focus of Apple to also create and sell design and user experience alongside great technology. But now that Apple is the most valuable company in the world, copying their success is a common undertaking. Great design is now a premium offering that everyone wants, from the one-person startup to the largest companies, consumer and enterprise. This emerging business paradigm will have significant impact across the user experience design process and profession. One area that particularly interests me is, how are we going to evaluate these new emerging “delight and excite” experiences, which are further customized to each particular domain? How to Measure “Delight and Excite” Traditional usability measures of task completion rate, assists, time, and errors are still extremely useful in many situations; however, they are too blunt to offer much insight into emerging experiences “Satisfaction” is usually assessed in user testing, in roughly equivalent importance to the above objective metrics. Various surveys and scales have provided ways to measure satisfying UX, with whatever questions they include. However, to meet the demands of new business goals and keep users at the center of design and development processes, we have to explore new methods to better capture custom-experience goals and emotion-driven user responses. We have had success assessing custom experiences, including “delight and excite”, by employing a variety of user testing methods that tend to combine formative and summative techniques (formative being focused more on identifying usability issues and ways to improve design, and summative focused more on metrics). Our most successful tool has been one we’ve been using for a long time, Magnitude Estimation Technique (MET). But it’s not necessarily about MET as a measure, rather how it is created. Caption: For one client, EchoUser did two rounds of testing.  Each test was a mix of performing representative tasks and gathering qualitative impressions. Each user participated in an in-person moderated 1-on-1 session for 1 hour, using a testing set-up where they held the phone. The primary goal was to identify usability issues and recommend design improvements. MET is based on a definition of the desired experience, which users will then use to rate items of interest (usually tasks in a usability test). In other words, a custom experience definition needs to be created. This can then be used to measure satisfaction in accomplishing tasks; “delight and excite”; or anything else from strategic goals, user demands, or elsewhere. For reference, our standard MET definition in usability testing is: “User experience is your perception of how easy to use, well designed and productive an interface is to complete tasks.” Articulating the User Experience We’ve helped construct experience definitions for several clients to better match their business goals. One example is a modification of the above that was needed for a company that makes medical-related products: “User experience is your perception of how easy to use, well-designed, productive and safe an interface is for conducting tasks. ‘Safe’ is how free an environment (including devices, software, facilities, people, etc.) is from danger, risk, and injury.” Another example is from a company that is pushing hard to incorporate “delight” into their enterprise business line: “User experience is your perception of a product’s ease of use and learning, satisfaction and delight in design, and ability to accomplish objectives.” I find the last one particularly compelling in that there is little that identifies the experience as being for a highly technical enterprise application. That definition could easily be applied to any number of consumer products. We have gone further than the above, including “sexy” and “cool” where decision-makers insisted they were part of the desired experience. We also applied it to completely different experiences where the “interface” was, for example, riding public transit, the “tasks” were train rides, and we followed the participants through the train-riding journey and rated various aspects accordingly: “A good public transportation experience is a cost-effective way of reliably, conveniently, and safely getting me to my intended destination on time.” To construct these definitions, we’ve employed both bottom-up and top-down approaches, depending on circumstances. For bottom-up, user inputs help dictate the terms that best fit the desired experience (usually by way of cluster and factor analysis). Top-down depends on strategic, visionary goals expressed by upper management that we then attempt to integrate into product development (e.g., “delight and excite”). We like a combination of both approaches to push the innovation envelope, but still be mindful of current user concerns. Hopefully the idea of crafting your own custom experience, and a way to measure it, can provide you with some ideas how you can adapt your user experience needs to whatever company you are in. Whether product-development or service-oriented, nearly every company is ultimately providing a user experience. The Bottom Line Creating great experiences may have been popularized by Steve Jobs and Apple, but I’ll be honest, it’s a good feeling to be moving from “good enough” to “delight and excite,” despite the challenge that entails. In fact, it’s because of that challenge that we will expand what we do as UX professionals to help deliver and assess those experiences. I’m excited to see how we, Oracle, and the rest of the industry will live up to that challenge.

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• Java EE 7 Survey Results!

  - by reza_rahman

  On November 8th, the Java EE EG posted a survey to gather broad community feedback on a number of critical open issues. For reference, you can find the original survey here. We kept the survey open for about three weeks until November 30th. To our delight, over 1100 developers took time out of their busy lives to let their voices be heard! The results of the survey were sent to the EG on December 12th. The subsequent EG discussion is available here. The exact summary sent to the EG is available here. We would like to take this opportunity to thank each and every one the individuals who took the survey. It is very appreciated, encouraging and worth it's weight in gold. In particular, I tried to capture just some of the high-quality, intelligent, thoughtful and professional comments in the summary to the EG. I highly encourage you to continue to stay involved, perhaps through the Adopt-a-JSR program. We would also like to sincerely thank java.net, JavaLobby, TSS and InfoQ for helping spread the word about the survey. Below is a brief summary of the results... APIs to Add to Java EE 7 Full/Web Profile The first question asked which of the four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. As the following graph shows, there was significant support for adding all the new APIs to the full profile: Support is relatively the weakest for Batch 1.0, but still good. A lot of folks saw WebSocket 1.0 as a critical technology with comments such as this one: "A modern web application needs Web Sockets as first class citizens" While it is clearly seen as being important, a number of commenters expressed dissatisfaction with the lack of a higher-level JSON data binding API as illustrated by this comment: "How come we don't have a Data Binding API for JSON" JCache was also seen as being very important as expressed with comments like: "JCache should really be that foundational technology on which other specs have no fear to depend on" The results for the Web Profile is not surprising. While there is strong support for adding WebSocket 1.0 and JSON-P 1.0 to the Web Profile, support for adding JCache 1.0 and Batch 1.0 is relatively weak. There was actually significant opposition to adding Batch 1. 0 (with 51.8% casting a 'No' vote). Enabling CDI by Default The second question asked was whether CDI should be enabled in Java EE environments by default. A significant majority of 73.3% developers supported enabling CDI, only 13.8% opposed. Comments such as these two reflect a strong general support for CDI as well as a desire for better Java EE alignment with CDI: "CDI makes Java EE quite valuable!" "Would prefer to unify EJB, CDI and JSF lifecycles" There is, however, a palpable concern around the performance impact of enabling CDI by default as exemplified by this comment: "Java EE projects in most cases use CDI, hence it is sensible to enable CDI by default when creating a Java EE application. However, there are several issues if CDI is enabled by default: scanning can be slow - not all libs use CDI (hence, scanning is not needed)" Another significant concern appears to be around backwards compatibility and conflict with other JSR 330 implementations like Spring: "I am leaning towards yes, however can easily imagine situations where errors would be caused by automatically activating CDI, especially in cases of backward compatibility where another DI engine (such as Spring and the like) happens to use the same mechanics to inject dependencies and in that case there would be an overlap in injections and probably an uncertain outcome" Some commenters such as this one attempt to suggest solutions to these potential issues: "If you have Spring in use and use javax.inject.Inject then you might get some unexpected behavior that could be equally confusing. I guess there will be a way to switch CDI off. I'm tempted to say yes but am cautious for this reason" Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations. A slight majority of 53.3% developers supported using @Inject consistently across JSRs. 28.8% said using custom injection annotations is OK, while 18.0% were not sure. The vast majority of commenters were strongly supportive of CDI and general Java EE alignment with CDI as illistrated by these comments: "Dependency Injection should be standard from now on in EE. It should use CDI as that is the DI mechanism in EE and is quite powerful. Having a new JSR specific DI mechanism to deal with just means more reflection, more proxies. JSRs should also be constructed to allow some of their objects Injectable. @Inject @TransactionalCache or @Inject @JMXBean etc...they should define the annotations and stereotypes to make their code less procedural. Dog food it. If there is a shortcoming in CDI for a JSR fix it and we will all be grateful" "We're trying to make this a comprehensive platform, right? Injection should be a fundamental part of the platform; everything else should build on the same common infrastructure. Each-having-their-own is just a recipe for chaos and having to learn the same thing 10 different ways" Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A significant majority of 62.3% developers supported expanding the use of @Stereotype, only 13.3% opposed. A majority of commenters supported the idea as well as the theme of general CDI/Java EE alignment as expressed in these examples: "Just like defining new types for (compositions of) existing classes, stereotypes can help make software development easier" "This is especially important if many EJB services are decoupled from the EJB component model and can be applied via individual annotations to Java EE components. @Stateless is a nicely compact annotation. Code will not improve if that will have to be applied in the future as @Transactional, @Pooled, @Secured, @Singlethreaded, @...." Some, however, expressed concerns around increased complexity such as this commenter: "Could be very convenient, but I'm afraid if it wouldn't make some important class annotations less visible" Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE... A very solid 96.3% of developers wanted to expand interceptor use to all Java EE components. 35.7% even wanted to expand interceptors to other Java EE managed classes. Most developers (54.9%) were not sure if there is any place that injection is supported that should not support interceptors. 32.8% thought any place that supports injection should also support interceptors. Only 12.2% were certain that there are places where injection should be supported but not interceptors. The comments reflected the diversity of opinions, generally supportive of interceptors: "I think interceptors are as fundamental as injection and should be available anywhere in the platform" "The whole usage of interceptors still needs to take hold in Java programming, but it is a powerful technology that needs some time in the Sun. Basically it should become part of Java SE, maybe the next step after lambas?" A distinct chain of thought separated interceptors from filters and listeners: "I think that the Servlet API already provides a rich set of possibilities to hook yourself into different Servlet container events. I don't find a need to 'pollute' the Servlet model with the Interceptors API"

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• DHCP reply packets do not make it into KVM instance in OpenStack

  - by Lorin Hochstein

  I'm running a KVM instance inside of OpenStack, and it isn't getting an IP address from the DHCP server. Using tcpdump, I can see the request and reply packets on vnet0 of the compute host: # tcpdump -i vnet0 -n port 67 or port 68 tcpdump: WARNING: vnet0: no IPv4 address assigned tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on vnet0, link-type EN10MB (Ethernet), capture size 65535 bytes 19:44:56.176727 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from fa:16:3e:46:f6:11, length 300 19:44:56.176785 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from fa:16:3e:46:f6:11, length 300 19:44:56.177315 IP 10.40.0.1.67 > 10.40.0.3.68: BOOTP/DHCP, Reply, length 319 19:45:02.179834 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from fa:16:3e:46:f6:11, length 300 19:45:02.179904 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from fa:16:3e:46:f6:11, length 300 19:45:02.180375 IP 10.40.0.1.67 > 10.40.0.3.68: BOOTP/DHCP, Reply, length 319 However, if I do the same thing on eth0 inside the KVM instance, I only see the request packets, not the reply packets. What would prevent the packets from making it from vnet0 of the host to eth0 of the guest? My host is running Ubuntu 12.04 and my guest is running CentOS 6.3. Note that I have added this rule in my iptables, but it doesn't resolve the issue: -A POSTROUTING -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill The instance corresponds to vnet0 and is connected via br100: # brctl show bridge name bridge id STP enabled interfaces br100 8000.54781a8605f2 no eth1 vnet0 vnet1 virbr0 8000.000000000000 yes Here's the full iptables-save: # Generated by iptables-save v1.4.12 on Tue Apr 2 19:47:27 2013 *nat :PREROUTING ACCEPT [8323:2553683] :INPUT ACCEPT [7993:2494942] :OUTPUT ACCEPT [6158:461050] :POSTROUTING ACCEPT [6455:511595] :nova-compute-OUTPUT - [0:0] :nova-compute-POSTROUTING - [0:0] :nova-compute-PREROUTING - [0:0] :nova-compute-float-snat - [0:0] :nova-compute-snat - [0:0] :nova-postrouting-bottom - [0:0] -A PREROUTING -j nova-compute-PREROUTING -A OUTPUT -j nova-compute-OUTPUT -A POSTROUTING -j nova-compute-POSTROUTING -A POSTROUTING -j nova-postrouting-bottom -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -p tcp -j MASQUERADE --to-ports 1024-65535 -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -p udp -j MASQUERADE --to-ports 1024-65535 -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -j MASQUERADE -A nova-compute-snat -j nova-compute-float-snat -A nova-postrouting-bottom -j nova-compute-snat COMMIT # Completed on Tue Apr 2 19:47:27 2013 # Generated by iptables-save v1.4.12 on Tue Apr 2 19:47:27 2013 *mangle :PREROUTING ACCEPT [7969:5385812] :INPUT ACCEPT [7905:5363718] :FORWARD ACCEPT [158:48190] :OUTPUT ACCEPT [6877:8647975] :POSTROUTING ACCEPT [7035:8696165] -A POSTROUTING -o virbr0 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill -A POSTROUTING -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill COMMIT # Completed on Tue Apr 2 19:47:27 2013 # Generated by iptables-save v1.4.12 on Tue Apr 2 19:47:27 2013 *filter :INPUT ACCEPT [2196774:15856921923] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [2447201:1170227646] :nova-compute-FORWARD - [0:0] :nova-compute-INPUT - [0:0] :nova-compute-OUTPUT - [0:0] :nova-compute-inst-19 - [0:0] :nova-compute-inst-20 - [0:0] :nova-compute-local - [0:0] :nova-compute-provider - [0:0] :nova-compute-sg-fallback - [0:0] :nova-filter-top - [0:0] -A INPUT -j nova-compute-INPUT -A INPUT -i virbr0 -p udp -m udp --dport 53 -j ACCEPT -A INPUT -i virbr0 -p tcp -m tcp --dport 53 -j ACCEPT -A INPUT -i virbr0 -p udp -m udp --dport 67 -j ACCEPT -A INPUT -i virbr0 -p tcp -m tcp --dport 67 -j ACCEPT -A FORWARD -j nova-filter-top -A FORWARD -j nova-compute-FORWARD -A FORWARD -d 192.168.122.0/24 -o virbr0 -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -s 192.168.122.0/24 -i virbr0 -j ACCEPT -A FORWARD -i virbr0 -o virbr0 -j ACCEPT -A FORWARD -o virbr0 -j REJECT --reject-with icmp-port-unreachable -A FORWARD -i virbr0 -j REJECT --reject-with icmp-port-unreachable -A OUTPUT -j nova-filter-top -A OUTPUT -j nova-compute-OUTPUT -A nova-compute-FORWARD -i br100 -j ACCEPT -A nova-compute-FORWARD -o br100 -j ACCEPT -A nova-compute-inst-19 -m state --state INVALID -j DROP -A nova-compute-inst-19 -m state --state RELATED,ESTABLISHED -j ACCEPT -A nova-compute-inst-19 -j nova-compute-provider -A nova-compute-inst-19 -s 10.40.0.1/32 -p udp -m udp --sport 67 --dport 68 -j ACCEPT -A nova-compute-inst-19 -s 10.40.0.0/16 -j ACCEPT -A nova-compute-inst-19 -p tcp -m tcp --dport 22 -j ACCEPT -A nova-compute-inst-19 -p icmp -j ACCEPT -A nova-compute-inst-19 -j nova-compute-sg-fallback -A nova-compute-inst-20 -m state --state INVALID -j DROP -A nova-compute-inst-20 -m state --state RELATED,ESTABLISHED -j ACCEPT -A nova-compute-inst-20 -j nova-compute-provider -A nova-compute-inst-20 -s 10.40.0.1/32 -p udp -m udp --sport 67 --dport 68 -j ACCEPT -A nova-compute-inst-20 -s 10.40.0.0/16 -j ACCEPT -A nova-compute-inst-20 -p tcp -m tcp --dport 22 -j ACCEPT -A nova-compute-inst-20 -p icmp -j ACCEPT -A nova-compute-inst-20 -j nova-compute-sg-fallback -A nova-compute-local -d 10.40.0.3/32 -j nova-compute-inst-19 -A nova-compute-local -d 10.40.0.4/32 -j nova-compute-inst-20 -A nova-compute-sg-fallback -j DROP -A nova-filter-top -j nova-compute-local COMMIT # Completed on Tue Apr 2 19:47:27 2013

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• Network traffic is not being forwarded from a VM to the network using a bridged interface with Xen + libvirt

  - by foob

  I'm having trouble getting network access from a VM that I'm running using Xen and libvirt. I've been trying different things and reading similar posts online for a couple of days but I'm really stuck at this point. If anybody could offer some insight it would be much appreciated. I have a VM that I'm running on a host with a bridge set up as br0 and an interface eth0 on a 192.168.60.0/24 subnet. The networking portion of the libvirt configuration xml is: <interface type='bridge'> <mac address='ff:a0:d1:e5:07:de'/> <source bridge='br0'/> <script path='/etc/xen/scripts/vif-bridge'/> <model type='virtio' /> </interface> When I start the VM a vif6.0 interface is created on the host and the ifconfig output is: br0 Link encap:Ethernet HWaddr 00:A0:D1:C3:07:DE inet addr:192.168.60.33 Bcast:192.168.60.255 Mask:255.255.255.0 inet6 addr: fe80::2a0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13 errors:0 dropped:0 overruns:0 frame:0 TX packets:40 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:3570 (3.4 KiB) TX bytes:3508 (3.4 KiB) eth0 Link encap:Ethernet HWaddr 00:A0:D1:C3:07:DE inet6 addr: fe80::2a0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:492 (492.0 b) Interrupt:19 Memory:fe8f0000-fe900000 vif6.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:80 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:6660 (6.5 KiB) TX bytes:468 (468.0 b) virbr0 Link encap:Ethernet HWaddr 00:00:00:00:00:00 inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) The 'brctl show' output seems to show the bridge being configured correctly: br0 8000.00a0d1e507de no eth0 vif6.0 The ifcfg-eth0 contents in the VM are: DEVICE=eth0 BOOTPROTO=static HWADDR=FF:A0:D1:E5:07:DE IPADDR=192.168.60.133 NETMASK=255.255.255.0 ONBOOT=yes and the output of ifconfig in the VM look like what I would expect: eth0 Link encap:Ethernet HWaddr FF:A0:D1:E5:07:DE inet addr:192.168.60.133 Bcast:192.168.60.255 Mask:255.255.255.0 inet6 addr: fe80::fda0:d1ff:fee5:7de/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:80 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:468 (468.0 b) TX bytes:7780 (7.5 KiB) but when I try to ssh or ping another computer I get 'no route to host.' Using tcpdump on the host system I tried to see if I could narrow down where the problem is: # tcpdump -vv -i vif6.0 tcpdump: WARNING: vif6.0: no IPv4 address assigned tcpdump: listening on vif6.0, link-type EN10MB (Ethernet), capture size 96 bytes 14:49:40.833997 arp who-has 192.168.60.35 tell 192.168.60.133 14:49:41.833314 arp who-has 192.168.60.35 tell 192.168.60.133 14:49:42.833309 arp who-has 192.168.60.35 tell 192.168.60.133 So the VM is sending out out an arp who-has packet when I try to ssh to 192.168.60.35. I think that this means the setup within the VM is ok and that this is an issue on the host system. If I run tcpdump with the interface of br0 then I don't see these arp packets. My thought here is that the packets are being blocked before going on to the bridge somehow. I tried adding an iptables rule to resolve this: -A FORWARD -m physdev --physdev-is-bridged -j ACCEPT but it didn't work. I also tried the following: /sbin/sysctl -w net.bridge.bridge-nf-call-ip6tables=0 /sbin/sysctl -w net.bridge.bridge-nf-call-iptables=0 /sbin/sysctl -w net.bridge.bridge-nf-call-arptables=0 /sbin/sysctl -w net.ipv4.ip_forward=1 which had no impact. Is it obvious to somebody who has more experience than me what I'm missing here? Should vif6.0 have the same MAC address is eth0 in the vm? Do I need more rules in my iptables? Thanks for any help!

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• What is Causing this IIS 7 Web Service Sporadic Connectivity Error?

  - by dpalau

  On sporadic occasions we receive the following error when attempting to call an .asmx web service from a .Net client application: "The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host." By sporadic I mean that it might occur zero, once every few days, or a half-dozen times a day for some users. It will never occur for the first web service call of a user. And the subsequent (usually the same) call will always work immediately after the failure. The failures happen across a variety of methods in the service and usually happens between 15-20 seconds (according to the log) from the time of the request. Looking in the IIS site log for the particular call will show one or the other of the following windows error codes: 121: The semaphore timeout period has elapsed. 1236: The network connection was aborted by the local system. Some additional environment details: Running on internal network web farm consisting of two servers running IIS7 on Windows Server 2008 OS. These problems did not occur when running in an older IIS6 web farm of three servers running on Windows Server 2003 (and we use a single IIS6/2003 instance for our development and staging environments with no issues). EDIT: Also, all of these server instances are VMWare virtual machines, not sure if that is a surprise anymore or not. The web service is a .Net 2.0/3.5 compiled .asmx web service that has its own application pool (.Net 2.0, integrated pipeline). Only has Windows Authentication enabled. We have another web service on the farm that uses the same physical path as the primary service, the only difference being that Basic Authentication is enabled. This is used for a portion of our ERP system. Have tried using the same and different application pool - no effect on the error. This site isn't hit as often as the primary site and has never had an error. As mentioned, the error will only happen when called from the .Net client - not from other applications. The client application is always creating a new web service object for each request and setting the service credentials to System.Net.CredentialCache.DefaultCredentials. The application is either deployed locally to a client or run in a Citrix server session. Those users running in Citrix doesn't seem to experience the issue, only locally deployed clients. The Citrix servers and the web farm are located in the same physical location and are located in the same IP range (10.67.xx.xx). Locally deployed clients experiencing the error are located elsewhere (10.105.xx.xx, 10.31.xx.xx). I've checked the OS logs to see if I can see any problems but nothing really sticks out. EDIT: Actually, I myself just ran into the error a little bit ago. I decided to check out the logs again and saw that there was a Security log entry of "Audit Failure" at the 'same' time (IIS log entry at 1:39:59, event log entry at 1:39:50). Not sure if this is a coincidence or not, I'll have to check out the logs of previous errors. I'm probably grasping for straws but the details: Log Name: Security Source: Microsoft-Windows-Security-Auditing Date: 7/8/2009 1:39:50 PM Event ID: 5159 Task Category: Filtering Platform Connection Level: Information Keywords: Audit Failure User: N/A Computer: is071019.<**.net Description: The Windows Filtering Platform has blocked a bind to a local port. Application Information: Process ID: 1260 Application Name: \device\harddiskvolume1\windows\system32\svchost.exe Network Information: Source Address: 0.0.0.0 Source Port: 54802 Protocol: 17 Filter Information: Filter Run-Time ID: 0 Layer Name: Resource Assignment Layer Run-Time ID: 36 I've also tried to use Failed Request Tracing in IIS7 but the service call never actually gets to where FRT can capture it (even though the failure is logged in the web service log). The network infrastructure group said they checked out the DNS and any NIC settings are correct so there is no 'flapping'. Everything pans out. I'm not sure that they checked out any domain controller servers though to see if that could be an issue. Any ideas? Or any other debugging strategies to get to the bottom of this? I'm just the developer in charge of the software and don't really have the knowledge on what to investigate from the networking side of things - although it does sound like a networking issue to me based on what is happening. Thanks in advance for any help.

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• LDAP over SSL with an EFI Fiery printer

  - by austinian

  I've got a printer with a Fiery running 8e Release 2. I can authenticate users against AD using the LDAP configuration, but I can only get it to work if I don't use SSL/TLS, and only if I use SIMPLE authentication. Right now, it's authenticating using a fairly low-impact user, but it's also the only system on our network that's not using LDAPS. I can get AD info fine over LDAPS using ldp.exe from my machine, our firewall, our mail filter, our linux boxes, etc. The only problem child is the Fiery. I've added the LDAP server certificate as a trusted cert to the Fiery, but after I check the box for Secure Communication and change the port to 636, pressing Validate results in a dialog box coming up saying: LDAP Validation Failed Server Name invalid or server is unavailable. I've tried changing the server name to use just the name, the FQDN, and the IP address, and changed it to another server, just to see if it was just this AD server that was fussy with the Fiery. EDIT: removed LDP output, added packet capture analysis from wireshark: The conversation seems pretty normal to me, up to the point where the Fiery terminates the connection after the server sends back a handshake response. Maybe they messed up their TLS implementation? I'm trying support, but it's been fairly useless so far. The cert is a SHA-2 (sha256RSA) 2048-bit certificate. Also, it looks like the Fiery is specifying TLS 1.0. Looking at http://msdn.microsoft.com/en-us/library/windows/desktop/aa374757(v=vs.85).aspx, I'm not seeing SHA256 and TLS 1.0 combination being supported by SChannel. headdesk perhaps that's why, after the DC changes the cipher spec, the connection is terminated by the Fiery? TLS 1.1 and 1.2 are enabled on the DC. Wireshark conversation: DC: 172.17.2.22, Fiery: 172.17.2.42 No. Time Source Source Port Destination Destination Port Protocol Length Info 1 0.000000000 172.17.2.42 48633 172.17.2.22 ldaps TCP 74 48633 > ldaps [SYN] Seq=0 Win=5840 Len=0 MSS=1460 SACK_PERM=1 TSval=3101761 TSecr=0 WS=4 2 0.000182000 Dell_5e:94:e3 Broadcast ARP 60 Who has 172.17.2.42? Tell 172.17.2.22 3 0.000369000 TyanComp_c9:0f:90 Dell_5e:94:e3 ARP 60 172.17.2.42 is at 00:e0:81:c9:0f:90 4 0.000370000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 74 ldaps > 48633 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1 TSval=67970573 TSecr=3101761 5 0.000548000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [ACK] Seq=1 Ack=1 Win=5840 Len=0 TSval=3101761 TSecr=67970573 6 0.001000000 172.17.2.42 48633 172.17.2.22 ldaps TLSv1 147 Client Hello 7 0.001326000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 1514 [TCP segment of a reassembled PDU] 8 0.001513000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 1514 [TCP segment of a reassembled PDU] 9 0.001515000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [ACK] Seq=82 Ack=1449 Win=8736 Len=0 TSval=3101761 TSecr=67970573 10 0.001516000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [ACK] Seq=82 Ack=2897 Win=11632 Len=0 TSval=3101761 TSecr=67970573 11 0.001732000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 1514 [TCP segment of a reassembled PDU] 12 0.001737000 172.17.2.22 ldaps 172.17.2.42 48633 TLSv1 1243 Server Hello, Certificate, Certificate Request, Server Hello Done 13 0.001738000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [ACK] Seq=82 Ack=4345 Win=14528 Len=0 TSval=3101761 TSecr=67970573 14 0.001739000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [ACK] Seq=82 Ack=5522 Win=17424 Len=0 TSval=3101761 TSecr=67970573 15 0.002906000 172.17.2.42 48633 172.17.2.22 ldaps TLSv1 78 Certificate 16 0.004155000 172.17.2.42 48633 172.17.2.22 ldaps TLSv1 333 Client Key Exchange 17 0.004338000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 66 ldaps > 48633 [ACK] Seq=5522 Ack=361 Win=66304 Len=0 TSval=67970573 TSecr=3101762 18 0.004338000 172.17.2.42 48633 172.17.2.22 ldaps TLSv1 72 Change Cipher Spec 19 0.005481000 172.17.2.42 48633 172.17.2.22 ldaps TLSv1 327 Encrypted Handshake Message 20 0.005645000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 66 ldaps > 48633 [ACK] Seq=5522 Ack=628 Win=66048 Len=0 TSval=67970574 TSecr=3101762 21 0.010247000 172.17.2.22 ldaps 172.17.2.42 48633 TLSv1 125 Change Cipher Spec, Encrypted Handshake Message 22 0.016451000 172.17.2.42 48633 172.17.2.22 ldaps TCP 66 48633 > ldaps [FIN, ACK] Seq=628 Ack=5581 Win=17424 Len=0 TSval=3101765 TSecr=67970574 23 0.016630000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 66 ldaps > 48633 [ACK] Seq=5581 Ack=629 Win=66048 Len=0 TSval=67970575 TSecr=3101765 24 0.016811000 172.17.2.22 ldaps 172.17.2.42 48633 TCP 60 ldaps > 48633 [RST, ACK] Seq=5581 Ack=629 Win=0 Len=0

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• Linux policy routing - packets not coming back

  - by Bugsik

  i am trying to set up policy routing on my home server. My network looks like this: Host routed VPN gateway Internet link through VPN 192.168.0.35/24 ---> 192.168.0.5/24 ---> 192.168.0.1 DSL router 10.200.2.235/22 .... .... 10.200.0.1 VPN server The traffic from 192.168.0.32/27 should be and is routed through VPN. I wanted to define some routing policies to route some traffic from 192.168.0.5 through VPN as well - for start - from user with uid 2000. Policy routing is done using iptables mark target and ip rule fwmark. The problem: When connecting using user 2000 from 192.168.0.5 tcpdump shows outgoing packets, but nothing comes back. Traffic from 192.168.0.35 works fine (here I am not using fwmark but src policy). Here is my VPN gateway setup: # uname -a Linux placebo 3.2.0-34-generic #53-Ubuntu SMP Thu Nov 15 10:49:02 UTC 2012 i686 i686 i386 GNU/Linux # iptables -V iptables v1.4.12 # ip -V ip utility, iproute2-ss111117 IPtables rules (all policies in table filter are ACCEPT) # iptables -t mangle -nvL Chain PREROUTING (policy ACCEPT 770K packets, 314M bytes) pkts bytes target prot opt in out source destination Chain INPUT (policy ACCEPT 767K packets, 312M bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 5520 packets, 1920K bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 782K packets, 901M bytes) pkts bytes target prot opt in out source destination 74 4707 MARK all -- * * 0.0.0.0/0 0.0.0.0/0 owner UID match 2000 MARK set 0x3 Chain POSTROUTING (policy ACCEPT 788K packets, 903M bytes) pkts bytes target prot opt in out source destination # iptables -t nat -nvL Chain PREROUTING (policy ACCEPT 996 packets, 51172 bytes) pkts bytes target prot opt in out source destination Chain INPUT (policy ACCEPT 7 packets, 432 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 1364 packets, 112K bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 2302 packets, 160K bytes) pkts bytes target prot opt in out source destination 119 7588 MASQUERADE all -- * vpn 0.0.0.0/0 0.0.0.0/0 Routing: # ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master lan state UNKNOWN qlen 1000 link/ether 00:40:63:f9:c3:8f brd ff:ff:ff:ff:ff:ff valid_lft forever preferred_lft forever 3: lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:40:63:f9:c3:8f brd ff:ff:ff:ff:ff:ff inet 192.168.0.5/24 brd 192.168.0.255 scope global lan inet6 fe80::240:63ff:fef9:c38f/64 scope link valid_lft forever preferred_lft forever 4: vpn: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100 link/none inet 10.200.2.235/22 brd 10.200.3.255 scope global vpn # ip rule show 0: from all lookup local 32764: from all fwmark 0x3 lookup VPN 32765: from 192.168.0.32/27 lookup VPN 32766: from all lookup main 32767: from all lookup default # ip route show table VPN default via 10.200.0.1 dev vpn 10.200.0.0/22 dev vpn proto kernel scope link src 10.200.2.235 192.168.0.0/24 dev lan proto kernel scope link src 192.168.0.5 # ip route show default via 192.168.0.1 dev lan metric 100 10.200.0.0/22 dev vpn proto kernel scope link src 10.200.2.235 192.168.0.0/24 dev lan proto kernel scope link src 192.168.0.5 TCP dump showing no traffic coming back when connection is made from 192.168.0.5 user 2000 # tcpdump -i vpn tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on vpn, link-type RAW (Raw IP), capture size 65535 bytes ### Traffic from user 2000 on 192.168.0.5 ### 10:19:05.629985 IP 10.200.2.235.37291 > 10.100-78-194.akamai.com.http: Flags [S], seq 2868799562, win 14600, options [mss 1460,sackOK,TS val 6887764 ecr 0,nop,wscale 4], length 0 10:19:21.678001 IP 10.200.2.235.37291 > 10.100-78-194.akamai.com.http: Flags [S], seq 2868799562, win 14600, options [mss 1460,sackOK,TS val 6891776 ecr 0,nop,wscale 4], length 0 ### Traffic from 192.168.0.35 ### 10:23:12.066174 IP 10.200.2.235.49247 > 10.100-78-194.akamai.com.http: Flags [S], seq 2294159276, win 65535, options [mss 1460,nop,wscale 4,nop,nop,TS val 557451322 ecr 0,sackOK,eol], length 0 10:23:12.265640 IP 10.100-78-194.akamai.com.http > 10.200.2.235.49247: Flags [S.], seq 2521908813, ack 2294159277, win 14480, options [mss 1367,sackOK,TS val 388565772 ecr 557451322,nop,wscale 1], length 0 10:23:12.276573 IP 10.200.2.235.49247 > 10.100-78-194.akamai.com.http: Flags [.], ack 1, win 8214, options [nop,nop,TS val 557451534 ecr 388565772], length 0 10:23:12.293030 IP 10.200.2.235.49247 > 10.100-78-194.akamai.com.http: Flags [P.], seq 1:480, ack 1, win 8214, options [nop,nop,TS val 557451552 ecr 388565772], length 479 10:23:12.574773 IP 10.100-78-194.akamai.com.http > 10.200.2.235.49247: Flags [.], ack 480, win 7776, options [nop,nop,TS val 388566081 ecr 557451552], length 0

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• Installing Windows on HP Proliant Servers without SmartStart

  - by Fitzroy

  I have a PXE server for deploying Windows XP and Windows 7 to workstations. The process is as follows: Boot the workstation from the NIC. Workstation sends a DHCP request. DHCP server responds with an IP address and the location of the PXE server. Workstation downloads WinPE image file from PXE server via TFTP Workstation stores WinPE image file in memory and executes it. Once booted into WinPE, I connect to a network share to gain access to either the Windows XP or Windows 7 installation files. A custom script is launched to guide you through the process of formatting and partitioning the hard drive(s) (using DISKPART and FORMAT). Another custom script asks for details such as the hostname to assign to the workstation. The answers provided are used to build an unattended answer file (SIF [Setup Information File] for WinXP and XML for Win7). The Windows setup EXE is launched, passing the unattended answer file to it as a parameter. The Windows XP and Windows 7 installation sources have been customised to include the drivers for our Dell workstations. They also run a number of scripts upon first booting up to install software packages. This process works very well for our workstations and I would now like to use it for building our servers too. The vast majority of our servers are HP Proliant DL360 G6, DL380 G5 and DL380 G6. They’re running Windows Server 2003 (various editions) or 2008 (various editions). To date, we have always built the HP Proliant servers using the SmartStart CD provided. SmartStart does three useful things for us: Setup RAID with HP Array Configuration Utility (ACU). Installs and configures SNMP Installs various HP Tools for Windows (HP Array Configuration Utility, HP Array Diagnostic Utility, HP Proliant Integrated Management Log Viewer, etc) Using SmartStart I have never had to manually download and install Windows drivers for network, sound, video, etc. I'm not sure if this is because SmartStart copies drivers from the CD during setup, or whether Windows just has the drivers natively in its driver CAB. If I abandon the SmartStart CD in favour of my PXE server I would have to do the following: As I wont have access to ACU, I'll configure the RAID (before booting to the PXE server) by pressing F8 (during the boot process) to access Option ROM Configuration for Arrays (ORCA). Installation of SNMP and the HP Tools will have to be installed once the Windows installation is complete using the Proliant Support Pack. Is this method OK? Is there anything that the SmartStart CD does that I'll be unable to do by other means? Are there any disadvantages to not using the SmartStart CD? Many thanks. UPDATE 05/01/12 I’ve been reading through the SmartStart Scripting Toolkit documentation. The scripting toolkit contains command line tools which work within WinPE and can such things as configure BIOS settings, configure an array and setup ILO. I’m personally not too bothered about configuring BIOS settings as I rarely deviate from the defaults (unless the server is to be a Hyper-V host). I’m not too fussed about being able to configure the array from within WinPE, as I’m happy to just press F8 and use Option ROM Configuration for Arrays (ORCA). Although, if it’s easy enough to do, I will explore this further, as it saves time if everything can be configured from within WinPE. One of the nice features all the tools possess is that you can pass input files to them. EG. Configure one server to your requirements, capture its configuration to a file (using the appropriate tool), you can then use the tool on other servers passing the input file with the captured configuration. Array controller drivers appear to be included with the toolkit along with example of how to incorporate them within a WinPE build. I suppose WinPE won’t be able to see logical volumes (I.E 2x physical disks in a RAID 1 configuration) without the array controller drivers? I mentioned in my post that SmartStart normally installs a bunch of Windows HP tools for you. I’ve had a look today, and if you run the SmartStart CD from within Windows all the tools can be installed. Therefore I can do this after the Windows installation is complete. The SmartStart CD appears to contain a lot Windows drivers. I can customise my Windows 2008 source to incorporate these drivers. However, I understand that incorporating an array controller driver is a little different to most drivers. I believe that you have to provide the driver during the very early stages of the Windows setup. I’m working through the Scripting Toolkit documentation to try and work this out...

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• Replies to request coming over a relay goes to relay's internal IP, not to original request's source IP

  - by seaquest

  Dhcpd running on Linux gets a dhcp request over dhcrelay which is running on other remote machine. Oct 6 10:09:46 2012 dhcpd: DHCPDISCOVER from 00:1e:68:06:eb:37 (oguz-U300) via 172.16.17.81 tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes 10:35:01.112500 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto: UDP (17), length: 328) 192.168.0.81.67 > 192.168.0.1.67: BOOTP/DHCP, Request from 00:1e:68:06:eb:37, length: 300, hops:1, xid:0xe378fc7e, flags: [none] (0x0000) Gateway IP: 172.16.17.81 Client Ethernet Address: 00:1e:68:06:eb:37 [|bootp] It matches to a subnet and send reply. However reply does not go to the requesting dhcrelay external IP(192.168.0.81). Instead, it goes to the internal interface IP of machine running dhcrelay. And I think because of this remote machine running dhcrelay or the dhcrealy itself discarding packet. Oct 6 10:09:46 2012 dhcpd: DHCPOFFER on 172.16.17.11 to 00:1e:68:06:eb:37 (oguz-U300) via 172.16.17.81 10:35:02.050108 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto: UDP (17), length: 328) 192.168.0.1.67 > 172.16.17.81.67: BOOTP/DHCP, Reply, length: 300, hops:1, xid:0xe378fc7e, flags: [none] (0x0000) Your IP: 172.16.17.11 Gateway IP: 172.16.17.81 Client Ethernet Address: 00:1e:68:06:eb:37 [|bootp] Is this a normal behaviour? Machine running dhcrelay: eth1(ext) Link encap:Ethernet HWaddr 00:90:0B:21:43:F4 inet addr:192.168.0.81 Bcast:192.168.0.255 Mask:255.255.255.0 eth2(int) Link encap:Ethernet HWaddr 00:90:0B:21:43:F5 inet addr:172.16.17.81 Bcast:172.16.17.255 Mask:255.255.255.0 3582 ? Ss 0:00 /usr/sbin/dhcrelay -i eth2 192.168.0.1 Machine running dhcpd: eth1 Link encap:Ethernet HWaddr 00:90:0B:23:97:D1 inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0 option domain-name "test.com"; option subnet-mask 255.255.255.0; authoritative; ignore client-updates; ddns-update-style ad-hoc; default-lease-time 86400; max-lease-time 86400; subnet 192.168.0.0 netmask 255.255.255.0 { range 192.168.0.135 192.168.0.169; option broadcast-address 192.168.0.255; option domain-name-servers 192.168.0.1; option domain-name "test.com"; option routers 192.168.0.1; } subnet 172.16.17.0 netmask 255.255.255.0 { local-address 192.168.0.1; server-identifier 192.168.0.1; range 172.16.17.10 172.16.17.11; option broadcast-address 172.16.17.255; option routers 172.16.17.81; } (I put local-address and server-identifier. But this does not help ) Regards, -- Oguz YILMAZ UPDATE: The first problem is found. I have configured dhcrelay only on listening internel interface. It seems (of course) is should also listen to external interface for replies. It appears it is not important where the packet destined to. dhrelay will forward it to internal net. HOWEVER, I have deleted route on dhcpd server to reach 172.16.17.x subnet. It again tries to send reply to 172.16.17.81. Because it does not know the route it send it from default gateway to the internet. eth0: IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto: UDP (17), length: 328) 192.168.1.2.67 > 172.16.17.81.67: BOOTP/DHCP, Reply, length: 300, hops:1, xid:0x32830125, secs:3, flags: [none] (0x0000) eth0: Your IP: 172.16.17.11 eth0: Gateway IP: 172.16.17.81 eth0: Client Ethernet Address: 00:1e:68:06:eb:37 [|bootp] How can I force dhcpd to force to send replies to requesting IP? Because, it is not much meaningful to add routes to subnet we distribute IP for. Internet - dhcpd - 192.168.0.1 - SOMENET - 192.168.0.81 - dhcrelay - 172.16.17.0/24 192.168.0.1 has no route for 172.16.17.0 and has no interface directly attached to that net.

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• Bind: dns not 'spreaded'

  - by realtebo

  I've elfoip.net with bind $ whois elfoip.net | grep 'Name Server' Name Server: NS.ELFOIP.NET I need elfoip.net be able to serve third levels domain, like mickymouse.elfoip.net, etc... Yes, I'm trying to create an other useless dyndns clone. i've added some third level as A RR. Eg: executing this from the server itself $ dig @localhost mattinauno.elfoip.net ;; ANSWER SECTION: mattinauno.elfoip.net. 60 IN A 192.81.221.113 I was expecting in one or two days, from my pc i can digit in browser mattinauno.elfoip.net and get page a 192.81.221.113 But this is not happening. Are there any prerequisites to satisfy to allow dns of my isp to be able to forward dns resolution of *.elfoip.net to MY dns ? (Or to ask to him and then cache ?) TTL of zone is set a 5m I've not AllowQuey directive, is it necessary for other dns to cache from mine ? I've cheched the zone with bind utility named-checkzone but no error detected. How to diagnose why other dns doesn't take in account RR from mine ? from my home pc dig @ns.elfoip.net mattinauno.elfoip.net ;; ANSWER SECTION: mattinauno.elfoip.net. 60 IN A 192.81.221.113 ;; AUTHORITY SECTION: elfoip.net. 300 IN NS ns.elfoip.net. but dig @8.8.8.8 mattinauno.elfoip.net give no answers Whole zone file: note I've used nsupdate, so this file has been re-edited and re-formatted from this utility ! root@mirko:/var/named# cat elfoip.net.db $ORIGIN . $TTL 300 ; 5 minutes elfoip.net IN SOA ns.elfoip.net. hostmaster.elfoip.net. ( 2013062314 ; serial 3600 ; refresh (1 hour) 600 ; retry (10 minutes) 86400 ; expire (1 day) 60 ; minimum (1 minute) ) NS ns.elfoip.net. A 109.168.99.6 $ORIGIN elfoip.net. $TTL 60 ; 1 minute google A 173.194.35.56 maiscai A 192.81.221.113 mattinadue A 192.81.221.113 mattinauno A 192.81.221.113 $TTL 300 ; 5 minutes ns A 109.168.99.6 $TTL 60 ; 1 minute prova A 208.67.222.222 prova2 A 13.23.34.45 A 13.23.34.46 www CNAME elfoip.net. EDIT: added named.conf.local zone "elfoip.net" { type master; // file "/etc/bind/elfoip.net.db"; file "/var/named/elfoip.net.db"; allow-update { key elfoip.net ; }; }; EDIT: I've no setup list-on directive *EDIT Added a TCPDUMP after [email protected] wwww.elfoip.net from a machine which uses my company internal dns, who allow recursive query. root@mirko:~# tcpdump -i eth0 'port 53' tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 11:57:23.293611 IP host9-210-static.22-87-b.business.telecomitalia.it.45958 > mirko.elfoip.net.domain: 61337+ A? www.elfoip.net. (32) 11:57:23.294114 IP mirko.elfoip.net.domain > host9-210-static.22-87-b.business.telecomitalia.it.45958: 61337* 2/1/1 CNAME elfoip.net., A 109.168.99.6 (95) 11:57:23.294554 IP mirko.elfoip.net.59571 > google-public-dns-a.google.com.domain: 45851+ PTR? 9.210.22.87.in-addr.arpa. (42) 11:57:23.330444 IP google-public-dns-a.google.com.domain > mirko.elfoip.net.59571: 45851 1/0/0 PTR host9-210-static.22-87-b.business.telecomitalia.it. (106) 11:57:23.331181 IP mirko.elfoip.net.44171 > google-public-dns-a.google.com.domain: 33339+ PTR? 8.8.8.8.in-addr.arpa. (38) 11:57:23.439405 IP google-public-dns-a.google.com.domain > mirko.elfoip.net.44171: 33339 1/0/0 PTR google-public-dns-a.google.com. (82) 11:57:31.350654 IP host9-210-static.22-87-b.business.telecomitalia.it.30108 > mirko.elfoip.net.domain: 38269 [1au] A? ns.elfoip.net. (42) 11:57:31.351117 IP mirko.elfoip.net.domain > host9-210-static.22-87-b.business.telecomitalia.it.30108: 38269* 1/1/1 A 109.168.99.6 (72) If i dig @8.8.8.8 www.elfoip.net, NOTHING happens in dump log !

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• RHEL Cluster FAIL after changing time on system

  - by Eugene S

  I've encountered a strange issue. I had to change the time on my Linux RHEL cluster system. I've done it using the following command from the root user: date +%T -s "10:13:13" After doing this, some message appeared relating to <emerg> #1: Quorum Dissolved however I didn't capture it completely. In order to investigate the issue I looked at /var/log/messages and I've discovered the following: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering GATHER state from 0. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Creating commit token because I am the rep. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Storing new sequence id for ring 354 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering COMMIT state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering RECOVERY state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [0] member 192.168.1.49: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 848 rep 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru 61 high delivered 61 received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Did not need to originate any messages in recovery. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Sending initial ORF token Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CMAN ] quorum lost, blocking activity Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [SYNC ] This node is within the primary component and will provide service. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering OPERATIONAL state. Mar 22 16:40:42 hsmsc50sfe1a kernel: dlm: closing connection to node 2 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a clurgmgrd[25809]: <emerg> #1: Quorum Dissolved Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 1 Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Cluster is not quorate. Refusing connection. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing connect: Connection refused Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-21). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing disconnect: Invalid request descriptor Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering GATHER state from 9. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Creating commit token because I am the rep. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Storing new sequence id for ring 358 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering COMMIT state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering RECOVERY state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [0] member 192.168.1.49: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 852 rep 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru f high delivered f received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [1] member 192.168.1.51: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 852 rep 192.168.1.51 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru f high delivered f received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Did not need to originate any messages in recovery. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Sending initial ORF token Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [SYNC ] This node is within the primary component and will provide service. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering OPERATIONAL state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [MAIN ] Node chb_sfe2a not joined to cman because it has existing state Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.51 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 2 Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Cluster is not quorate. Refusing connection. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing connect: Connection refused Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-111). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing get: Invalid request descriptor Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-21). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing disconnect: Invalid request descriptor How could this be related to the time change procedure I performed?

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• Windows 7 cannot join samba domain

  - by Antonis Christofides

  I have a 3.5.6 samba server with a LDAP backend (both on Debian 6.0). I've been successfully adding Windows XP machines to the domain for years. I now try to add Windows 7. I have made the recommended registry changes, but I don't have any success so far. Here is what happens: 1. I go to computer name, select "Domain" instead of "Workgroup", type in the domain name, click OK. It asks me for the username and password of an account that can add computers to the domain; I enter them. After about 40 seconds, I get the following message: The following error occurred attempting to join the domain "ITIA": The specified computer account could not be found. Contact an administrator to verify the account is in the domain. If the account has been deleted unjoin, reboot, and rejoin the domain. Despite this, the samba server successfully creates the computer account. 2. Therefore, if I try again a second time, without deleting the already created computer account, I get a different error: The following error occurred attempting to join the domain "ITIA": The specified account already exists. (Note that until a while ago samba wasn't configured to automatically create computer accounts. What I did whenever I wanted an XP to join was to manually create it. When I first attempted to solve the Windows 7 join problem, I setup samba to do this automatically, as this is what most people do, as I understand, and I thought that it might be related. I haven't attempted to add an XP since I made this change, so I don't know if it works, but whether it works or not, the problem remains.) Update 1: Here are the relevant parts of smb.conf: [global] panic action = /usr/share/samba/panic-action %d workgroup = ITIA server string = Itia file server announce as = NT interfaces = 147.102.160.1 volume = %h passdb backend = ldapsam:ldap://ldap.itia.ntua.gr:389 ldap admin dn = uid=samba,ou=daemons,dc=itia,dc=ntua,dc=gr ldap ssl = off ldap suffix = dc=itia,dc=ntua,dc=gr ldap user suffix = ou=people ldap group suffix = ou=groups ldap machine suffix = ou=computers unix password sync = no add machine script = smbldap-useradd -w -i %u log file = /var/log/samba/samba-log.all log level = 3 max log size = 5000 syslog = 2 socket options = SO_KEEPALIVE TCP_NODELAY encrypt passwords = true password level = 1 security = user domain master = yes local master = no wins support = yes domain logons = yes idmap gid = 1000-2000 Update 2: The server has a single network interface eth1 (also an unused eth0 that shows up only in the kernel boot messages) and two ip addresses; the main, 147.102.160.1, and an additional one, 147.102.160.37, that comes up with "ip addr add 147.102.160.37/32 dev eth1" (used only for a web site that has a different certificate than other web sites served from the same machine). One of the problems I recently faced was that samba was using the latter IP address. I fixed that by adding the "interfaces = 147.102.160.1" statement in smb.conf. Now: acheloos:/etc/apache2# tcpdump host 147.102.160.40 and not port 5900 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:13:56.549048 IP lithaios.itia.civil.ntua.gr.netbios-dgm > 147.102.160.255.netbios-dgm: NBT UDP PACKET(138) 13:13:56.549056 ARP, Request who-has acheloos2.itia.civil.ntua.gr tell lithaios.itia.civil.ntua.gr, length 46 13:13:56.549091 ARP, Reply acheloos2.itia.civil.ntua.gr is-at 00:10:4b:b4:9e:59 (oui Unknown), length 28 13:13:56.549324 IP acheloos.itia.civil.ntua.gr.netbios-dgm > lithaios.itia.civil.ntua.gr.netbios-dgm: NBT UDP PACKET(138) 13:13:56.549608 IP lithaios.itia.civil.ntua.gr.netbios-dgm > acheloos2.itia.civil.ntua.gr.netbios-dgm: NBT UDP PACKET(138) 13:13:56.549741 IP acheloos.itia.civil.ntua.gr.netbios-dgm > lithaios.itia.civil.ntua.gr.netbios-dgm: NBT UDP PACKET(138) 13:13:56.550364 IP lithaios.itia.civil.ntua.gr.netbios-dgm > acheloos.itia.civil.ntua.gr.netbios-dgm: NBT UDP PACKET(138) 13:13:56.550468 IP acheloos.itia.civil.ntua.gr.netbios-dgm > lithaios.itia.civil.ntua.gr.netbios-dgm: NBT UDP PACKET(138) (acheloos2 is the second IP address, 147.102.160.37). The above dump occurs when I click "OK" (to join the domain), until it asks me for the username and password of a user that can join the domain. I don't know why the client is contacting the second IP address. I tried temporarily deactivating it, but I still had some related ARP traffic (though I think not IP traffic).

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• slow DNS resolution

  - by Ehsan

  I have a DNS server that resolves all queries for an internal group of servers. It is a bind on CentOS 5.5 (same as RHEL5) and I have set it up to allow recursion and resolve direction without any forwarders. The problem I am facing is that it takes a freakishly long amount of time to resolve a name for the first time. (in the magnitudes of 20 sec) This causes clients to give timeout. When I set it to forward all to Google's public DNS, i.e. 8.8.8.8+8.8.4.4, it works very nicely (within a second). I tried monitoring the traffic on the net to see why it is doing this: [root@ns1 ~]# tcpdump -nnvvvA -s0 udp tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 23:06:36.137797 IP (tos 0x0, ttl 64, id 35903, offset 0, flags [none], proto: UDP (17), length: 60) 172.17.1.10.36942 > 172.17.1.4.53: [udp sum ok] 19773+ A? www.paypal.com. (32) E..<[email protected]... .....N.5.(6.M=...........www.paypal.com..... 23:06:36.140594 IP (tos 0x0, ttl 64, id 56477, offset 0, flags [none], proto: UDP (17), length: 71) 172.17.1.4.6128 > 192.35.51.30.53: [udp sum ok] 10105 [1au] A? www.paypal.com. ar: . OPT UDPsize=4096 (43) E..G....@........#3....5.3fR'y...........www.paypal.com.......)........ 23:06:38.149756 IP (tos 0x0, ttl 64, id 13078, offset 0, flags [none], proto: UDP (17), length: 71) 172.17.1.4.52425 > 192.54.112.30.53: [udp sum ok] 54892 [1au] A? www.paypal.com. ar: . OPT UDPsize=4096 (43) [email protected]&.....6p....5.3.q.l...........www.paypal.com.......)........ 23:06:40.159725 IP (tos 0x0, ttl 64, id 43016, offset 0, flags [none], proto: UDP (17), length: 71) 172.17.1.4.24059 > 192.42.93.30.53: [udp sum ok] 11205 [1au] A? www.paypal.com. ar: . OPT UDPsize=4096 (43) E..G....@..@.....*].]..5.3..+............www.paypal.com.......)........ 23:06:41.141403 IP (tos 0x0, ttl 64, id 35904, offset 0, flags [none], proto: UDP (17), length: 60) 172.17.1.10.36942 > 172.17.1.4.53: [udp sum ok] 19773+ A? www.paypal.com. (32) E..<.@..@..@... .....N.5.(6.M=...........www.paypal.com..... 23:06:42.169652 IP (tos 0x0, ttl 64, id 44001, offset 0, flags [none], proto: UDP (17), length: 60) 172.17.1.4.9141 > 192.55.83.30.53: [udp sum ok] 1184 A? www.paypal.com. (32) E..<[email protected].#..5.(...............www.paypal.com..... 23:06:42.207295 IP (tos 0x0, ttl 54, id 38004, offset 0, flags [none], proto: UDP (17), length: 205) 192.55.83.30.53 > 172.17.1.4.9141: [udp sum ok] 1184- q: A? www.paypal.com. 0/3/3 ns: paypal.com. NS ns1.isc-sns.net., paypal.com. NS ns2.isc-sns.com., paypal.com. NS ns3.isc-sns.info. ar: ns1.isc-sns.net. AAAA 2001:470:1a::1, ns1.isc-sns.net. A 72.52.71.1, ns2.isc-sns.com. A 38.103.2.1 (177) E....t..6./A.7S......5#..................www.paypal.com..................ns1.isc-sns.net..............ns2.isc-sns...............ns3.isc-sns.info..,.......... ..p.............,..........H4G..I..........&g.. (this goes on for a few more seconds) If you look carefully, you will see that the first 3-4 root servers did not respond at all. This wastes 7-8 seconds, until one of them responded. Do you think I have setup something wrong here? Interestingly, when I dig directly from the root servers that did not respond, the always respond very fast (showing the firewall/nat is not the issue here). E.g. dig www.paypal.com @192.35.51.30 works perfectly, consistently, and very fast. What do you think about this mystery?

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• How to take the snapshot of a IE webpage through a BHO (C#)

  - by Kapil

  Hi, I am trying to build an IE BHO in C# for taking the snapshot of a webpage loaded in the IE browser. Here is what I'm trying to do: public class ShowToolbarBHO : BandObjectLib.IObjectWithSite { IWebBrowser2 webBrowser = null; public void SetSite (Object site) { ....... if (site != null) { ...... webBrowser = (IWebBrowser2)site; ...... } } } Also, I p/invoke the following COM methods: [Guid("0000010D-0000-0000-C000-000000000046")] [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)] [ComImportAttribute()] public interface IViewObject { void Draw([MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] IntPtr ptd, IntPtr hdcTargetDev, IntPtr hdcDraw, [MarshalAs(UnmanagedType.LPStruct)] ref COMRECT lprcBounds, [In] IntPtr lprcWBounds, IntPtr pfnContinue, int dwContinue); int GetColorSet([MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] IntPtr ptd, IntPtr hicTargetDev, [Out] IntPtr ppColorSet); int Freeze([MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, out IntPtr pdwFreeze); int Unfreeze([MarshalAs(UnmanagedType.U4)] int dwFreeze); int SetAdvise([MarshalAs(UnmanagedType.U4)] int aspects, [MarshalAs(UnmanagedType.U4)] int advf, [MarshalAs(UnmanagedType.Interface)] IAdviseSink pAdvSink); void GetAdvise([MarshalAs(UnmanagedType.LPArray)] out int[] paspects, [MarshalAs(UnmanagedType.LPArray)] out int[] advf, [MarshalAs(UnmanagedType.LPArray)] out IAdviseSink[] pAdvSink); } [StructLayoutAttribute(LayoutKind.Sequential)] public class COMRECT { public int left; public int top; public int right; public int bottom; public COMRECT() { } public COMRECT(int left, int top, int right, int bottom) { this.left = left; this.top = top; this.right = right; this.bottom = bottom; } } [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)] [ComVisibleAttribute(true)] [GuidAttribute("0000010F-0000-0000-C000-000000000046")] [ComImportAttribute()] public interface IAdviseSink { void OnDataChange([In]IntPtr pFormatetc, [In]IntPtr pStgmed); void OnViewChange([MarshalAs(UnmanagedType.U4)] int dwAspect, [MarshalAs(UnmanagedType.I4)] int lindex); void OnRename([MarshalAs(UnmanagedType.Interface)] object pmk); void OnSave(); void OnClose(); } Now When I take the snapshot: I make a call CaptureWebScreenImage((IHTMLDocument2) webBrowser.document); public static Image CaptureWebScreenImage(IHTMLDocument2 myDoc) { int heightsize = (int)getDocumentAttribute(myDoc, "scrollHeight"); int widthsize = (int)getDocumentAttribute(myDoc, "scrollWidth"); Bitmap finalImage = new Bitmap(widthsize, heightsize); Graphics gFinal = Graphics.FromImage(finalImage); COMRECT rect = new COMRECT(); rect.left = 0; rect.top = 0; rect.right = widthsize; rect.bottom = heightsize; IntPtr hDC = gFinal.GetHdc(); IViewObject vO = myDoc as IViewObject; vO.Draw(1, -1, (IntPtr)0, (IntPtr)0, (IntPtr)0, (IntPtr)hDC, ref rect, (IntPtr)0, (IntPtr)0, 0); gFinal.ReleaseHdc(); gFinal.Dispose(); return finalImage; } I am not getting the image of the webpage. Rather I am getting an image with black background. I am not sure if this is the right way of doing it, but I found over the web that IViewObject::Draw method is used for taking the image of a webpage in IE. I was earlier doing the image capture using the Native PrintWindow() method as mentioned in the following codeproject's page - http://www.codeproject.com/KB/graphics/IECapture.aspx But the image size is humongous! I was trying to see if I can reduce the size by using other techniques. It would be great if someone can point out the mistakes (I am sure there would be many) in my code above. Thanks, Kapil

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