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• Throwing an exception while handling an exception

  - by FredOverflow

  If a destructor throws in C++ during stack unwinding caused by an exception, the program terminates. (That's why destructors should never throw in C++.) If a finally block is entered in Java because of an exception in the corresponding try block and that finally block throws another exception, the first exception is silently swallowed. This question crossed my mind: Could a programming language handle multiple exceptions being thrown at the same time? Would that be useful? Have you ever missed that ability? Is there a language that already supports this? Is there any experience with such an approach? Any thoughts?

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• Handling User Authentication in C#.NET?

  - by Daniel

  I am new to .NET, and don't have much experience in programming. What is the standard way of handling user authentication in .NET in the following situation? 1.In Process A, User inputs ID/Password 2.Process A sends the ID/Password to Process B over a nonsecure public channel. 3.Process B authenticates the user with the recieved ID/Password what are some of the standard cryptographic algorithms I can use in above model? The users(customers that bought my company's software) will be running the software(Process A) locally in their computer(connected to internet). I need to authenticate the users so that only registered users can run the program. Thank You!

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• How do you keep a balance between working, training, health and family?

  - by Jim Burger

  One trend I see in the awesome developers I've met, is that they devote inordinate amounts of time to coding at the expense of (usually) their health. Personally, I also find it hard to motivate myself to keep healthy. Every now and again, I meet a fantastic coder who has it clocked; they are up to date with the latest dev news, have time to read about good programming practices, and to finish it off, have happy wives/husbands and families. How do you guys/gals manage it in the short 24 hours a day that we all have?

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• Help a Python newbie with a Django model inheritance problem

  - by Joshmaker

  I'm working on my first real Django project after years of PHP programming, and I am running into a problem with my models. First, I noticed that I was copying and pasting code between the models, and being a diligent OO programmer I decided to make a parent class that the other models could inherit from: class Common(model.Model): self.name = models.CharField(max_length=255) date_created = models.DateTimeField(auto_now_add=True) date_modified = models.DateTimeField(auto_now=True) def __unicode__(self): return self.name class Meta: abstract=True So far so good. Now all my other models extend "Common" and have names and dates like I want. However, I have a class for "Categories" were the name has to be unique. I assume there should be a relatively simple way for me to access the name attribute from Common and make it unique. However, the different methods I have tried to use have all failed. For example: class Category(Common): def __init__(self, *args, **kwargs): self.name.unique=True Spits up the error "Caught an exception while rendering: 'Category' object has no attribute 'name' Can someone point me in the right direction?

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• What web browser engine, version, and capabilities are used to display web pages inside Visual Studio 2010?

  - by Phrogz

  My company is developing a plugin/add-on for Visual Studio 2010. When the user asks to display the help for our product, we plan on opening an HTML page (or suite of pages) within Visual Studio. I'm helping to design and implement the help system. What web engine/version is used within Visual Studio 2010? According to Wikipedia it is not Trident(!). Am I allowed to load remote JavaScript content (via a <script> element)? Am I allowed to use XHR to load remote content? Will my page be trusted and have access to the FileSystemObject? I would appreciate any resources you can give me on programming specifically to the 'web' capabilities of VisualStudio2010-as-a-browser.

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• Popularity of Git/Mercurial/Bazaar vs. which to recommend

  - by Will Robertson

  Going by the number of questions on this site for these three distributed version control systems, it seems like Git either is more popular, or is more difficult (hence requiring more questions), or has more features (hence requiring more questions). Or most probably a combination of the three. (Let's say that popularity on this site equates to popularity at large.) Here are the numbers at time of writing: [subversion] or [svn]: 2353 [git]: 726 [mercurial] or [hg]: 169 [bazaar] or [bzr]: 50 The recent historical popularity of Subversion is clearly reflected by the number of questions, indicating at least a small tipping of the scales towards Git over the Mercurial or Bazaar. It's not entirely satisfactory having three competing yet largely equivalent open source products to choose from. Personally I use Git and I'm fine with the other two. But when it comes to recommending one system over the others, I'd like to ask: can we start recommending one safely yet?

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• use multiple views in an application

  - by Gaurav Arora

  Hi All, I am new to Iphone programming. So please don't mind if I ask some basic questions. :mad: I want to develop an application where the landing screen will be a login screen and after login application should display a new screen with the list of available categories. And on selecting any category a new screen should appear with the information related to the selected category. Basically I want to display different screens in the applications and my confusion is how can I make different screens with one .xib file? or should I use different .xib files for each screen. If I use different .xib files for each screen then how should I navigate to different screens. Please help in solving this confusion. Thanks in advance Gaurav

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• I am preparing to integrate Disqus with BlogEngine.NET. Any suggestions?

  - by Brennan

  I have an existing site running BlogEngine.NET 1.5 and will be upgrading it to the new 1.6 release. I have been asked to integrate Disqus for comments. I have not found any other questions on Disqus and BlogEngine.NET. I have found some specific instructions here: http://www.hamishgraham.net/post/Enabling-Disqus-Comments-in-BlogEngineNET.aspx It explains how to add Disqus to a specific BE.NET theme. But I have existing blog posts and comments. How will these 2 systems work side-by-side? Is there a way to somehow make Disqus work well with the existing comments? Links: http://www.dotnetblogengine.net/ http://disqus.com/

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• C-array to NSData and back

  - by Thor Frølich

  I'm attempting to save a c-style array of Vertex3D structs to an NSData object and get them back when reloading the app: NSData *vert = [NSData dataWithBytes:&vertices length:(sizeof(Vertex3D) * NUM_OF_VERTICES)]; This data is then saved and attempted to be read back into my c-array thusly: vertices = malloc(sizeof(Vertex3D) * NUM_OF_VERTICES); [vert getBytes:&vertices length:(sizeof(Vertex3D) * NUM_OF_VERTICES)]; The above results in “EXC_BAD_ACCESS” followed by: malloc: * error for object 0x48423c0: pointer being freed was not allocated I'm very new to programming so there's probably some fundamental memory management principle I'm unaware of. I have verified that the loaded NSData is identical to the saved one, but it's clear that the transition from c-array to NSData (and back) is not as I intended.

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• .NET Active Directory Password Expiration on Windows 2008

  - by Brent Pabst

  Searched SO and Everywhere else, including the .net developers guide to directory services programming book - no luck. I am trying to create a simple password reset web page that allows the user to change their password. The change password portion of the code is working fine. For the users I would also like to display when their current password will expire next. Using the sample code from the book mentioned above I was able to get all of the code setup however, the attribute that is returned is always equal to Long.MinValue and hence cannot be inverted to a positive number, plus this means it did not find the proper domain setting. Does anyone have sample code or references for getting the password expiration in a Windows 2008 or R2 domain environment where password policies can be different for each user?

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• PHP voting system with sessions?

  - by pingu

  Hi guys, I've been reading up on stackoverflow about creating voting systems in PHP that minimize abuse/multiple voting from the same user, but I haven't come across the answer to my question. I've got an application where users don't need to register to vote or "like" an entry. Obviously, I want to minimize abuse and I don't want to limit votes per IP address because some organisations (mine included) use shared IP addresses. I've never used sessions in a non-authenticated system before, but since this application is centered around entry votes I was wondering if this approach would work and whether there were any disadvantages such as performance implications, and whether it's even possible to use sessions in this way: start a session when the website is loaded allow one vote per item per session If this is a bad idea, my alternative options would be to allow a reasonable number of votes per IP address (say 25), or put a time limit between votes from the same IP address. What do you guys recommend?

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• Mac OS X: Intel vs. PPC marketshare

  - by benc

  I was looking at my plugins, and ended up looking at Silverlight on several Mac systems. What I noticed (from Wikipedia), was that only Silverlight 1 runs on PPC. Without knowing about the technical details and trade-offs, I was surprised. On its face, if you build Silverlight 1 for PPC and Intel, would it have been hard to continue to support both chipsets? So, assuming this was a decision based on marketshare, I tried to search for information on the Mac OS PPC vs. Intel marketshare, but could not find anything on point. Does anyone here have an idea what the ratio is? It seems like the most important architectural/product decision you would make for a Mac OS X product.

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• Who is a web developer? What does he do

  - by Sinan

  I am wrting an article on web developers. It seems to me there are some problems on the definition of "what is a web developer". It looks like a web developer title is a bit misunderstood. And people with this title doesnt get the recognition they deserve. While most people at IT have some well defined job defitinitions. A web developer requires multiple skills. Like knowing a programming language, web security, etc. I was wondering what do you think about this issue? What skills does a web developer need? Where does his responsibilities start and end? etc.

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• Load XML to DataFrame in R

  - by Rohit Kandhal

  I am new to R programming and trying to load a simple XML in RStudio. I tried using XMLToDataFrame but got this error XML content does not seem to be XML: 'temp.xml' XML Schema <root> <row Id="1" UserId="1" Name="Rohit" Date="2009-06-29T10:28:58.013" /> <row Id="2" UserId="3" Name="Rohit" Date="2009-06-29T10:28:58.030" /> </root> Please provide me some direction on which function I should use here.

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• Technologies used in Remote Administration applications(not RD)

  - by Michael

  I want to know what kind of technologies are used nowadays as underlying screen capture engine for remote administration software like VNC pcAnywhere TeamViewer RAC Remote Administrator etc.. The programming language is not so important as just to know whether a driver needs to be developed which is polling video memory 30 times per second or there are any com objects built in the Windows kernel to help doing this? I'm not interested in 3rd party components for doing this. Do I have to use DirectX facilities? Just want some start point to develop my own screen stream capture engine, which will be less CPU hog.

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• multiplayer / visitors interactions with Ruby on Rails?

  - by Jordi

  I want to have interactions between visitors on my site. Imagine a chat room. It basically involves getting the data from everyone and sending it to everyone, this can be done by ajax and what not but I wonder if there is something already there in the wild that would do the heavy lifting for me. I have to say that I got very lost once I start programming Ajax, dont even know how to make tests for it... I have found the Q42multiplayer library that looks like what I want but they use C# as backend. There is something similar or any other multiplayer thingy I can get some idea or rip some code from (the whole thing will be opensource) for Ruby on Rails?

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• Comparing Clojure books

  - by Michiel Borkent

  Currently there is (afaik) one completed Clojure book available: Programming Clojure by Stuart Halloway. Two are being written and partially available at Manning: The Joy of Clojure by Fogus and Houser Clojure in Action by Amit Rathore Another one is about to be published in May: Practical Clojure (The Definitive Guide) by Luke Van der Hart Are these books more or less the same and meant as a general introduction to Clojure? Does it make sense to buy them all, or is there a risk of having three very similar books? Will there be books that go into more specialized areas of Clojure and targetted for 'intermediate' or 'advanced' Clojure programmers?

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• mysql, sqlite database source code

  - by Yang

  hi guys, i know implementing database is a huge topic, but i want to have a basic understanding of how database systems works (e.g. memory management, binary tree, transaction, sql parsing, multi-threading, partitions, etc) by investigating the source code of the database, since there are a few already proven very robust open source databases like mysql, sqlite and so on. however, the code are very complicated and i have no clue where to start. also i find that the old school database textbooks are only explaining the theory, not the implementation details. Can anyone suggest how should i get started and is there any books that emphasis on the technology and techniques of building dbms used in modern database industry? Thank in advance!

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• Problems with installing jcc and pylucene

  - by Christian

  I'm trying to install pylucene on Windows XP. I installed JDK on C:\Programme\Java\jdk1.6.0_18 . I also installed Visual Studio C++ Express to have a C++ compiler. As first step I'm trying to integrate jcc into python2.6 through the command: C:\Python26\python.exe setup.py build This gives me the following result: C:\Installfiles\pylucene-3.0.1-1\jcc>C:\Python26\python.exe setup.py build Traceback (most recent call last): File "setup.py", line 332, in <module> main('--debug' in sys.argv) File "setup.py", line 289, in main raise type(e), "%s: %s" %(e, args) WindowsError: [Error 2] Das System kann die angegebene Datei nicht finden: ['jav ac.exe', '-d', 'jcc/classes', 'java/org/apache/jcc/PythonVM.java', 'java/org/apa che/jcc/PythonException.java'] Other information: In systems I set: Uservariables: CLASSPATH C:\Programme\Java\jdk1.6.0_18\bin\javac.exe System Variables Path %SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem; C:\Programme\Java\jdk1.6.0_18\bin Where does the error come from and what do I have to do to overcome it?

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• Why is my app running

  - by John Smith

  I have compiled my iPhone app with setting (Device, Release). I install it on the test machine and it runs with no problem. Here's the problem. The app is linked to a C++ library. The compilation on the simulator has no errors. However the device compilation produces 568 errors, mostly about different visibilities w.r.t AppDelegate.o. They all look like: QL::Error::~Error()has different visibility (default) in /QL/build/Release-iphoneos/libQLLibrary.a(abcd.o) and (hidden) in /Programming/ObjC/Second/build/Second.build/Release-iphoneos/FG.build/Objects-normal/armv6/AppDelegate.o Why is this, and how can I stop the errors anyway?

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• Return a pointer to a char array in C

  - by snitko

  I've seen a lot of questions on that on StackOverflow, but reading the answers did not clear that up for me, probably because I'm a total newbie in C programming. Here's the code: #include <stdio.h> char* squeeze(char s[], char c); main() { printf("%s", squeeze("hello", 'o')); } char* squeeze(char s[], char c) { int i, j; for(i = j = 0; s[i] != '\0'; i++) if(s[i] != c) s[j++] = s[i]; s[j] = '\0'; return s; } It compiles and I get segmentation fault when I run it. I've read this faq about about returning arrays and tried the 'static' technique that is suggested there, but still could not get the program working. Could anyone point out exactly what's wrong with it and what should I be paying attention in the future?

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• Eclipse IDE's Hello World Cheatsheet seems to have a mistake

  - by Sean

  Hey guys, Just a warning: I'm completely new to Java and am trying to teach myself Android programming. I installed the Eclipse IDE today and tried to walk through the first Java Hello World "cheat sheet," and it didn't work! I was really quite surprised. When it asked me to select the checkbox to create the main() method, there wasn't anything on-screen that looked like a checkbox with "main()" or "method" next to it, so I guessed that maybe what they meant was the "Modifiers" radio button. So I left that checked for "public." It didn't compile and I got red X's next to every folder in my Package Explorer. Has anybody else had this problem? Thanks!

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• Warning: Ignoring library 'com.motorola.android.iextdispservice', missing property value

  - by user1342684

  Hi I am trying to get my eclipse environment setup so I can start playing with programming for android... The Android SDK Manager is installing the following packages (everything else says installed except these two): Android 2.3.3 (API 10) Dual Screen APIs - Not Installed Android 2.2 (API 8) Dual Screen APIs - Not Installed Error Messages: [2012-04-19 13:06:41 - SDK Manager] Warning: Ignoring library 'com.motorola.android.iextdispservice', missing property value [2012-04-19 13:15:27 - SDK Manager] Operation timed out [2012-04-19 13:18:16 - SDK Manager] Operation timed out Any tips? So close to getting the environment ready! I want to start playing around!

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• Project roles discovery

  - by Lirik

  I have a school project in which we're going to write a financial engine prototype by a group of 4 people. Most of us have never met each other before, so I'm trying to create a questionnaire to help us find the appropriate roles for each team-member. We have the following responsibilities: Database design Programming User interface design Training Documentation / technical writing Network design Project management Business analysis Testing And we have the following roles: Project Manager Developer Tester Business Analyst Our group has people with various experience: a full-time graduate student, an associate director at the CME (Chicago Mercantile Exchange), full-time professionals, etc. Do any of you know of any tools that would help build a questionnaire or do you have a reference to an online questionnaire that can help us identify the most suitable role(s) for each team member?

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• CentOS Client - Unable to Establish iSCSI connection with multiple interfaces on the initiator

  - by slashdot

  So after upgrading to CentOS 6.2, I am seemingly no longer able to login into my iSCSI targets. I have multiple interfaces on different subnets on the system, and I first thought that it had to do with the fact that I may not be binding correct interfaces, which seems to be the case when looking at netstat, as this is clearly wrong: [root]? netstat -na|grep .90 tcp 0 1 10.10.100.60:42354 10.10.8.90:3260 SYN_SENT tcp 0 1 10.10.100.60:40777 10.10.9.90:3260 SYN_SENT I then went ahead and disabled all but one interface, and so as a result netstat appears to be correct, but the issue with login remains. I am positive that the target never sees a packet, because I see nothing by SYN_SENT. I know the problem is on my client, because the target is servicing multiple systems, none of which are CentOS 6.2. At this point I am pretty confident that some things changed between CentOS 6.0/6.1 and 6.2. So, if anyone have any thoughts, or ran into this, I would very much like to hear your thoughts. [root]? iscsiadm --mode node --targetname iqn.2011-12.dom.homer:01:lab-centos-servers-00001 --portal 10.10.8.90:3260,2 --interface=sw-iscsi-0 --login Logging in to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260] (multiple) iscsiadm: Could not login to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not log into all portals [root]? netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.10.8.0 0.0.0.0 255.255.255.0 U 0 0 0 eth2.7 10.10.9.0 0.0.0.0 255.255.255.0 U 0 0 0 eth3.7 10.10.100.0 0.0.0.0 255.255.252.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth2 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth3 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth2.7 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth3.7 0.0.0.0 10.10.100.1 0.0.0.0 UG 0 0 0 eth0 Output of ip addr show for the two interfaces involved: [root]? for i in 2.7 3.7; do ip addr show eth$i; done 6: eth2.7@eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:0c:29:94:5b:8d brd ff:ff:ff:ff:ff:ff inet 10.10.8.60/24 brd 10.10.8.255 scope global eth2.7 inet6 fe80::20c:29ff:fe94:5b8d/64 scope link valid_lft forever preferred_lft forever 7: eth3.7@eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP link/ether 00:0c:29:94:5b:97 brd ff:ff:ff:ff:ff:ff inet 10.10.9.60/24 brd 10.10.9.255 scope global eth3.7 inet6 fe80::20c:29ff:fe94:5b97/64 scope link valid_lft forever preferred_lft forever Update 01/06/2012: This issue is getting even more interesting by the day it seems. I went a few weeks back and grabbed a snapshot of this system from before upgrading to 6.2. I spun up a new system from the snapshot, and reconfigured interface info and host keys, as well as iSCSI initiator and iscsi interface info to match new MACs. Changed nothing else. Then, I attempted to connect to my targets, and no issues at all. I cannot say that this was unexpected. I then went ahead and compared sysctl settings from both systems and there were differences after the upgrade, but nothing seemingly relevant to iSCSI or IP that could contribute to this. I also noticed that by default now two sessions per connection were enabled after the upgrade, but I changed it back to 1 session in /etc/iscsi/iscsid.conf. On the problematic system we can see that source interface is seemingly wrong, but even when I disable the 10.10.100 interface, problems persist. So, while this may be relevant, I could not validate it for certain. Needless to say, further research is necessary. Something is clearly different between releases. Working system is on 6.1, and non-working is 6.2. ::Working System:: tcp 0 0 10.10.8.210:39566 10.10.8.90:3260 ESTABLISHED tcp 0 0 10.10.9.210:46518 10.10.9.90:3260 ESTABLISHED [root]? ip route show 10.10.8.0/24 dev eth2.6 proto kernel scope link src 10.10.8.210 10.10.9.0/24 dev eth3.7 proto kernel scope link src 10.10.9.210 10.10.100.0/22 dev eth0 proto kernel scope link src 10.10.100.210 169.254.0.0/16 dev eth0 scope link metric 1002 169.254.0.0/16 dev eth2.6 scope link metric 1006 169.254.0.0/16 dev eth3.7 scope link metric 1007 default via 10.10.100.1 dev eth0 ::Non-working System:: tcp 0 1 10.10.100.60:44737 10.10.9.90:3260 SYN_SENT tcp 0 1 10.10.100.60:55479 10.10.8.90:3260 SYN_SENT [root]? ip route show 10.10.8.0/24 dev eth2.6 proto kernel scope link src 10.10.8.60 10.10.9.0/24 dev eth3.7 proto kernel scope link src 10.10.9.60 10.10.100.0/22 dev eth0 proto kernel scope link src 10.10.100.60 169.254.0.0/16 dev eth0 scope link metric 1002 169.254.0.0/16 dev eth2.6 scope link metric 1006 169.254.0.0/16 dev eth3.7 scope link metric 1007 default via 10.10.100.1 dev eth0 And the result is still same: [root]? iscsiadm: Could not login to [iface: sw-iscsi-0, target: iqn.2011-12.dom.homer:01:lab-centos-servers-00001, portal: 10.10.8.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not login to [iface: sw-iscsi-1, target: iqn.2011-12.dom.homer:02:lab-centos-servers-00001, portal: 10.10.9.90,3260]. iscsiadm: initiator reported error (8 - connection timed out) iscsiadm: Could not log into all portals Update 01/08/2012: I believe I have been able to figure out the answer to my issue. It is quite obscure and I doubt this will happen to anyone else any time soon. It turns out that setting iface.iscsi_ifacename and iface.hwaddress in the interfaces configuration file is not legal. When one manually adds an iscsi target, such as below, all settings from the interface config file are copied into the node config file, that gets created by the below command. Result is parameters iface.iscsi_ifacename and iface.hwaddress together in the same config file. These parameters are seemingly mutually exclusive, which does not exactly make sense, or there is perhaps an oversight in the codepath. Perhaps I will investigate further. # iscsiadm -m node --op new -T iqn.2011-12.dom.homer:01:lab-centos-servers-00001 -p 10.10.8.90,3260,2 -I sw-iscsi-0 # iscsiadm -m node --op new -T iqn.2011-12.dom.homer:02:lab-centos-servers-00001 -p 10.10.9.90,3260,2 -I sw-iscsi-1 Notice, below I commented out iface.hwaddress and iface.ipaddress, after which I re-added targets, with same command as above. All works just fine. [root]? cat * # BEGIN RECORD 2.0-872.33.el6 iface.iscsi_ifacename = sw-iscsi-0 iface.net_ifacename = eth2.6 #iface.hwaddress = XX:XX:XX:XX:XX:XX #iface.ipaddress = 10.10.8.60 iface.transport_name = tcp iface.vlan_id = 6 iface.vlan_priority = 0 iface.iface_num = 0 iface.mtu = 0 iface.port = 0 # END RECORD # BEGIN RECORD 2.0-872.33.el6 iface.iscsi_ifacename = sw-iscsi-1 iface.net_ifacename = eth3.7 #iface.hwaddress = XX:XX:XX:XX:XX:XX #iface.ipaddress = 10.10.9.60 iface.transport_name = tcp iface.vlan_id = 7 iface.vlan_priority = 0 iface.iface_num = 0 iface.mtu = 0 iface.port = 0 # END RECORD Again, chances of this happening to someone else are slim to none, so likely waste of time typing this up. But, if someone does encounter this issue, I hope this post will help.

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