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  • =?UTF-8?B??= in Emails sent via php mail problem

    - by Camran
    I have a website, and in the "Contact" section I have a form which users may fill in to contact me. The form is a simple form which action is a php page. The php code: $to = "[email protected]"; $name=$_POST['name']; // sender name $email=$_POST['email']; // sender email $tel= $_POST['tel']; // sender tel $subject=$_POST['subject']; // subject CHOSEN FROM DROPLIST, ALL TESTED $text=$_POST['text']; // Message from sender $text.="\n\nTel:".$tel; // Added to message to show me the telephone nr to the sender at bottom of message $headers="MIME-Version: 1.0"."\n"; $headers.="Content-type: text/plain; charset=UTF-8"."\n"; $headers.="From: $name <$email>"."\n"; mail($to, '=?UTF-8?B?'.base64_encode($subject).'?=', $text, $headers, '[email protected]'); Could somebody please tell me why this works most of the time, but sometimes I receive email whith no text and the subject line showing =?UTF-8?B??= I use outlook express, and I have read this http://stackoverflow.com/questions/454833/system-net-mail-and-utf-8bxxxxx-headers but it didn't help. The problem is not in Outlook, because when I log in to the actual mailprogram where I fetch the POP3 emails from, the email looks the same. When I right click in Outlook and chose "message source" then there is no "From" information. Ex, a good message should look like this: Subject: =?UTF-8?B?w5Z2cmlndA==?= MIME-Version: 1.0 Content-type: text/plain; charset=UTF-8 From: John Doe However, the ones with problem looks like this: Subject: =?UTF-8?B??= MIME-Version: 1.0 Content-type: text/plain; charset=UTF-8 From: As if the information has been lost somewhere. You should know also that I have a VPS, which I manage myself. I use postfix as an emailserver, if thats got anything to do with it. But then again, why does it work sometimes? Also another thing that I have noticed is that sometimes special characters are not shown correctly (by both Outlook and the webmail). For instance, the name "Björkman" in swedish is shown like Björkman, but again, only sometimes. I hope anybody knows something about this problem, because it is very hard to track down for me atleast. If you need more input let me know.

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  • How to conform to update-rc.d with LSB standard?

    - by user34881
    This is a migrated question from stackoverflow, as I was told, this is the place for it to be. http://stackoverflow.com/questions/2263567/how-to-conform-to-update-rc-d-with-lsb-standard I have set up a simple script to back up some directories. While I haven't had any problems setting up the functionality, I'm stuck with adding the script to rcX.d dir's using update-rc.d. My script: #! /bin/sh ### BEGIN INIT INFO # Provides: backup # Required-Start: backup # Required-Stop: # Should-Stop: # Default-Start: 0 6 # Default-Stop: # Description: Backs up some dirs ### END INIT INFO check_mounted() { # Check if HD is mounted } do_backup() { if check_mounted; then # Some rsync statements. fi } case "$1" in start) do_backup ;; restart|reload|force-reload) echo "Error: argument '$1' not supported" >&2 exit 3 ;; stop|"") # No-op ;; *) echo "Usage: backup [start]" >&2 exit 3 ;; esac : Using update-rc.d backup start 10 0 6 . I get the following warnings and errors: update-rc.d: warning: backup start runlevel arguments (none) do not match LSB Default-Start values (0 6) update-rc.d: warning: backup stop runlevel arguments (0 6.) do not match LSB Default-Stop values (none) update-rc.d: error: start|stop arguments not terminated by "." The syntax I try to use is the following: update-rc.d [-n] <basename> start|stop NN runlvl [runlvl] [...] . Google wasn't that helpful at finding a solution. How can I correctly set up a script and add it via update-rc.d? I'm using Ubuntu 9.10. UPDATE Using update-rc.d backup start 10 0 6 . stop 10 0 . the error disappears. The warnings about default values persists: update-rc.d: warning: backup start runlevel arguments (none) do not match LSB Default-Start values (0 6) update-rc.d: warning: backup stop runlevel arguments (0 6 0 6) do not match LSB Default-Stop values (none) It even is added to the appropiate rcX-dirs but it still does not get executed...

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  • Problems set-up Single Sign-On using Kerberos authentication

    - by user1124133
    I need for Ruby on Rail application set authentication via Active Directory using Kerberos authentication. Some technical information: I are using Apache installed mod_auth_kerb In httpd.conf I added LoadModule auth_kerb_module modules/mod_auth_kerb.so In /etc/krb5.conf I added following configuration [logging] default = FILE:/var/log/krb5libs.log kdc = FILE:/var/log/krb5kdc.log admin_server = FILE:/var/log/kadmind.log [libdefaults] default_realm = EU.ORG.COM dns_lookup_realm = false dns_lookup_kdc = false ticket_lifetime = 24h forwardable = yes [realms] EU.ORG.COM = { kdc = eudc05.eu.org.com:88 admin_server = eudc05.eu.org.com:749 default_domain = eu.org.com } [domain_realm] .eu.org.com = EU.ORG.COM eu.org.com = EU.ORG.COM [appdefaults] pam = { debug = true ticket_lifetime = 36000 renew_lifetime = 36000 forwardable = true krb4_convert = false } When I test kinit validuser and enter password then authentication is successful. klist returns: Ticket cache: FILE:/tmp/krb5cc_600 Default principal: [email protected] Valid starting Expires Service principal 02/08/13 13:46:40 02/08/13 23:46:47 krbtgt/[email protected] renew until 02/09/13 13:46:40 Kerberos 4 ticket cache: /tmp/tkt600 klist: You have no tickets cached In application Apache configuration I added IfModule mod_auth_kerb.c> Location /winlogin> AuthType Kerberos AuthName "Kerberos Loginsss" KrbMethodNegotiate off KrbAuthoritative on KrbVerifyKDC off KrbAuthRealms EU.ORG.COM Krb5Keytab /home/crmdata/httpd/apache.keytab KrbSaveCredentials off Require valid-user </Location> </IfModule> I restarted apache Now some tests: When I try to access application from Win7, I got pop-up message box, with text: Warning: This server is requesting that your username and password be sent in an insecure manner (basic authentification without a secure connection) When I enter valid credentials then my application opens successfully, and all works fine. Questions: Is ok that for user pop-ups such windows? If I use NTLM authentication then there no such pop-up. I checked IE Internet Options and there 'Enable Integrated Windows Authentication' is checked. Why IE try to send username and password to application apache? If I correct to understand then Windows self must make authentication via Active Directory using Kerberos protocol. When I try to access application from Win7 and I enter incorrect credentials to pop-up message box Application say Authentication failed (this is OK) In apache error log I see: [error] [client 192.168.56.1] krb5_get_init_creds_password() failed: Client not found in Kerberos database But now I cannot get possibility to enter valid credentials, only when I restart IE I can get again pop-up box. What could be incorrect or missing in my Kerberos setup? I read in some blog post that probably something is needed to be done in Active Directory side. What exactly?

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  • Why doesn't video run smoothly on my laptop anymore?

    - by andygrunt
    This might be an impossible question to answer remotely but I figure there may be some common causes that people can suggest so I think it's worth asking... Video no longer plays smoothly on my laptop. It used to but not for a while now. For example, playing a video on YouTube is pretty typical: I press play (making sure it's not on HD or even HQ) and the video buffers a little then starts to play. At first it plays fine then the video starts to stutter, turning into a slideshow while the sound continues to play smoothly. If I try playing the same video on my Playstation 3 (which is linked to the same network) it plays smoothly so it can't be the connection. Another example is streaming DivX videos. Again, I wait while it buffers and it starts but very soon, instead of a slideshow, this time the video just plays slowly while the sound continues as normal (instantly getting out of sync). Even if I let the video fully load before pressing play (i.e. it's no longer streaming), it still behaves the same way. I can even let it load 100% then save the file to hard disk and use VLC player to view it, and the same thing happens. I'm using an old laptop running Windows XP. For the past several years it's been connected to the router via Wi-Fi but in the past few days I've changed that to a network cable (like my PS3) but that hasn't helped. Yes, I regularly install various bits and pieces of software but nothing that I can identify as being the cause. So, are there known causes of this sort of behaviour and if so, what can I do to fix it? Thanks. Update to answer a few questions... Laptop Spec' (note: video has played back fine for the majority of time I've had the laptop) Toshiba Satellite 1900-603 (possibly called something else outside the UK) Intel Pentium 4 2.2 Ghz Processor Originally had 512Mb memory but recently doubled that to 1 Gig of memory Graphics: ATI Mobility Radeon 16Mb DDR VRAM Windows XP SP3 (Home edition) Over the years I've done several things to speed it up (disabling indexing etc) and am generally happy with the performance. I also regularly have a clear out of old software (if for no other reason than the laptop only has a 40Gb hard disk) and use CCleaner and Glary Utilities to strip out much of the crap from my system. Also recently (after doubling the memory), I've tried a few new things which might be likely candidates for slowing the video down such as Rocketdock, Jingle keyboard (which gives an old style 'clacky' typewriter sound when I type - love it), SugarSync, Taskbar Shuffle. However, the video doesn't play smoothly even when I try quit all these apps.

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  • networked storage for a research group, 10-100 TB

    - by Marc
    this is related to this post: http://serverfault.com/questions/80854/scalable-24-tb-nas-for-research-department but perhaps a little more general. Background: We're a research lab of around 10 people who do a lot of experiments that involve taking pictures at one of several lab setups and then analyzing it an one of several lab computers. Each experiment may produce 2 or 3 GB of data, and we are generating data at the rate of about 10 TB/year. Right now, we are storing the data on a 6-bay netgear readynas pro, but even with 2 TB drive, this only gives us 10 TB of storage. Also, right now we are not backing up at all. Our short term backup plan is to get a second readynas, put it in a different building and mirror the one drive onto the other. Obviously, this is somewhat non-ideal. Our options: 1) We can pay our university $400/ TB /year for "backed up" online storage. We trust them more than we trust us, but not a whole lot. 2) We can continue to buy small NASs and mirror them between offices. One limit, although stupid, is that we don't have an unlimited number of ethernet jacks. 3) We can try to implement our own data storage solution, which is why I'm asking you guys. One thing to consider is that we're a very transient population and none of us are network administration experts. I will probably be here only another year or so, and graduate students, who are here the longest, have a 5-6 year time scale. So nothing can require expert oversight. Our data transfer rates are low - most of the data will just sit on the server waiting for someone to look at it once or twice - so we don't need a really high speed system. Given these contraints, can someone recommend a fairly low-cost, scalable, more or less turn key shared data storage system with backup in a separate physical location. Does such a thing exist or should we just pay the university to take care of it for us? As a second question, our professor just got tenure and is putting together a budget. Here the goal is to ask for as much as you can and hope you get a fraction of it. So the same question, minus the low-cost. Without budget constraints, can you recommend a scalable turn-key backed up storage system. Thanks

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  • Is there a switch that will connect directly to my modem and allow my router to serve only as a WiFi connection?

    - by Abner
    Details . . Devices . Internets -50Mbps Cable Internet Modem - Motorola Surfboard Extreme Router - Netgear WNDR3700v3 Switch - D-Link DGS-1008G Wired Ethernet Cable - Cat6_24Awg_ Device Configuration - Modem\Router\Switch . . Internet Usage . Wired Demand XBOX 360 1 Gaming PC 2 PC - HD video . WiFi Demand 3 android + 1 Laptop for browsing and group video chat simultaneously . . Specifics . I am experiencing problems with network speeds and reliability on both wired and wireless connections. On many occasions I experience WiFi Speeds that vary between the 15mbps to 0.50 mbs (or less) and ping ranging from 15ms to 500ms. These results are from when I notice problems with internet lag and run speedtest.net to get details of problems. I have a stretched out floor-plan and old building materials drastically affecting my cellphone signal strength as well). After Reading the "Known Issues" Section on the webpage below http://www.dd-wrt.com/wiki/index.php/Netgear_WNDR3700#Known_Issues I bought the switch and Cat6 cable to increase speed and relieve stress on router in an attempt to fix the symptoms. I thought I'd use the router in a Modem\Switch\Router configuration. I thought I'd only have to use the router for mobile WiFi connections like android or Laptops when necessary (hopefully eliminating the problem caused by the router when subjected to all those demanding Ethernet connections) When I started unboxing the switch, I noticed the manual of this DGS-1008G shows it being connected in the Modem\Router\Switch order and not in the Modem\Switch\Router configuration I was aiming for. I have not been able to find a solid plan to remedy my specific problem without buying another expensive router. I would like to get the speeds I am paying for without buying another router. (My WiFi Adapters would also need to be updated if new router is required, meaning more $$$). I can always sell the switch and get a better one that will bypass the router because my most demanding internet connections are Wired. . . Questions Can I accomplish a Modem\Switch\Router configuration with current switch? Is there a different way to get the wired speed I need while providing WiFi only when necessary? . .

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  • Upgrading php from php 5.3 to 5.4 .7

    - by Takingsides
    So, quickly so to speak I have noticed this topic around, I have searched and there are plenty of solutions. However these solutions do not work for me, not only that but I'm intending to learn more about the Debian based OS. Questions I would like to know how to upgrade php5.3 to php 5.4.7 compiling it from source, myself without using a third-party ppa. Is the way (explained below) the correct way of configuring php5.4? I'm new to compiling from source. Set-up I run Ubuntu Server 12.04 64bit. I've currently got: PHP 5.3 MySQL-Server Apache2 Memcached The Problem So I initially installed php5.3 using apt-get. I now wish to upgrade the php 5.4 due to the advantage of traits in OOP and the struct with Arrays and all the other recent patches and such. Possible Solutions I've seen this ondrej/ppa repository, which I refuse to use, given the fact that it may work, but it's an unknown/untrusted source. ALso, i'm not learning how to administer from source, using configure, make and install accordingly. I've seen a solution compiling from source, which is essentially how I was hoping to go about it with some guidance. Conclusion So I didn't just expect to be spoon-fed, and I went out and did some manual reading and atleast started the ball rolling myself; this how far i've got. The first thing I did was su into root (to save the typing sudo all the darn time). $ sudo su The next thing I did was download the latest version of php (5.4.7) and extracted it's contents ready to configure before installing it. $ mkdir php5-new && cd !$ $ wget -O php-5.4.7.tar.bz2 http://php.net/get/php-5.4.7.tar.bz2/from/uk3.php.net/mirror $ bzip2 -d php-5.4.7.tar.bz2 $ tar xvf php-5.4.7.tar.gz $ cd php-5.4.7 $ ./configure --help Finally I decided to have a bash, I looked through the list of options and decided I needed to list ALL of the things I wanted to include in the configuration. $ ./configure --with-mysql --with-apache2 --with-libxml --with-openssl --with-zlib --with-bz2 --with-curl --with-dom --with-gd --with-imap --with-imap-ssl --with-mcrypt --with-mysqli --with-pdo-mysql --with-libxml --enable-ftp --enable-mbstring --enable-soap Finally, the results... When the configuration process had finished, it threw an error: configure: error: xml2-config not found. Please check your libxml2 installation.

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  • Scaling a video processing application on EC2?

    - by Stpn
    I am approaching the need to scale a video-processign application that runs on EC2. So far the setup is one machine: Backbonejs frontend Rails 3.2 Postgresql Resque + S3 for storage The flow of the app is as follows: 1) Request from frontend. Upload a video. 2) Storing video 3) Quering external APIs. 4) Processing / encoding videos. 5) Post to frontend. I can separate the backend and frontend without any problems, but when it comes to distributing the backend between several servers I am a bit puzzled. I can probably come up with a temporary solution (like just duplicating apps making several instances), but since I don't really have expertise in backend system administration, there can be some fundamental mistakes.. Also I would rather have something that is scalable. I wonder if anyone can give some feedback on the following plan: A) Frontend machine. Just frontend, talks to backend via REST Api of sorts. B) Backend server (BS), main database. Gets request from 1), posts to 2) saves uploads to 3) C) S3 storage. D) Server for quering APIs. Basically just a Resque workers, that post info back to 2) E) Server for video encoding. Processes videos uploaded on 3) and uploads them back. So I will have: A)frontend \ \ B)MAIN_APP/DB ----- C)S3 Storage (Files) / \ / / \ / D)ExternalAPI_queries E)Video_Processing (redundant DB) (redundant DB) All this will supposedly talk to each other via HTTP requests. My reason for this is that Video Processing part is really the most resource-intensive and I would just run barebones application that accepts requests and starts processing them. Questions: 1) In this setup I will have the main database at B) and all other servers will communicate with it via HTTP requests (and store duplicates of databases also I guess..for safety reasons). Is it the right approach or should I have 1 database that everyone connects to (how then?) 2) Is it a good idea to separate API queries from Video Processing part? Logically they are very close (processing is determined by the result of API queries), but resource-wise Video Processing is waaay more intensive. 3) what should I use to distribute calls between backend apps based on load?

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  • When upgrading from Vista to Windows 7 on a DELL laptop, how do I know which drivers to reinstall an

    - by msorens
    According to Dell's upgrade page for Vista to Windows 7, after using the upgrade assistant the final step is to install drivers. They refer to this page for the order of driver installation, listing 9 items. From there I go to the Dell Drivers and Downloads page, enter my system tag, and get a list of the downloads available for my specific box. That page, by the way, has a link to driver install instructions that lists 10 rather than 9 items. Going to Drivers Help in the side panel and clicking on "In what order should drivers be installed?" shows yet a third list, this one containing 13 items. Not surprisingly, the order of these 3 lists of drivers are not quite the same for the common items! Furthermore, of the 26 files Dell's site recommends for my machine, there are several not shown on any of the 3 lists! I can make determinations for some of these: 6 of them are "applications" so I know which of those I want and that they could probably be safely installed after all drivers. BIOS: I would think this should be unaffected by an OS upgrade so could be skipped. Two tools in the diagnostics category: could probably be done after all drivers. That leaves just a CD/DVD driver and a webcam driver unaccounted for. So my two related questions are these: How critical is the driver installation order and which one do I follow? (Keep in mind this is for an upgrade, not a fresh install.) Where in the order do I insert the CD/DVD and the webcam drivers (if needed) ? Dell's driver download page provides (in theory) the list of all downloads relevant to my specific machine, via the service tag. But do I actually need to reinstall all of them? some? none? How does one determine this? They do label each with Recommended or Optional, so do I need to reinstall all the recommended ones? (Part of the reason for my perplexed frown is that I wonder why I would need to reinstall a CD/DVD driver since I would already be using the drive to install the OS!)

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  • Reasons for missing IP info in `last` output on pts logins?

    - by Mike Pennington
    I have five CentOS 6 linux systems at work, and encountered a rather strange issue that only seems to happen with my userid across all the linux systems I have... This is an example of the problem from entries I excepted from the last command... mpenning pts/19 Fri Nov 16 10:32 - 10:35 (00:03) mpenning pts/17 Fri Nov 16 10:21 - 10:42 (00:21) bill pts/15 sol-bill.local Fri Nov 16 10:19 - 10:36 (00:16) mpenning pts/1 192.0.2.91 Fri Nov 16 10:17 - 10:49 (12+00:31) kkim14 pts/14 192.0.2.225 Thu Nov 15 18:02 - 15:17 (4+21:15) gduarte pts/10 192.0.2.135 Thu Nov 15 12:33 - 08:10 (11+19:36) gduarte pts/9 192.0.2.135 Thu Nov 15 12:31 - 08:10 (11+19:38) kkim14 pts/0 :0.0 Thu Nov 15 12:27 - 15:17 (5+02:49) gduarte pts/6 192.0.2.135 Thu Nov 15 11:44 - 08:10 (11+20:25) kkim14 pts/13 192.0.2.225 Thu Nov 15 09:56 - 15:17 (5+05:20) kkim14 pts/12 192.0.2.225 Thu Nov 15 08:28 - 15:17 (5+06:49) kkim14 pts/11 192.0.2.225 Thu Nov 15 08:26 - 15:17 (5+06:50) dspencer pts/8 192.0.2.130 Wed Nov 14 18:24 still logged in mpenning pts/18 alpha-console-1. Mon Nov 12 14:41 - 14:46 (00:04) You can see two of my pts login entries above that do not have a source IP address associated with them. My CentOS machines have as many as six other users that share the systems, but the mpenning userid is the only one that has this issue. Approximately 5% of my logins see this issue, but no other usernames exhibit this behavior. Questions Given the kind of scripts I keep on these systems (which control much of our network infrastructure), I'm a little spooked by this and would like to understand what would cause my logins to occasionally miss source addresses. Is there anything (other than malicious activity) that would reasonably explain the behavior? Other than bash history timestamping, are there other things I can do to track the issue down? Informational Since this started happening, I enabled bash history time-stamping (i.e. HISTTIMEFORMAT="%y-%m-%d %T " in .bash_profile) and also added a few other bash history hacks; however, that does not give clues to what happened during the previous occurrences. All the systems run CentOS 6.3... [mpenning@typo ~]$ uname -a Linux typo.local 2.6.32-279.9.1.el6.x86_64 #1 SMP Tue Sep 25 21:43:11 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux [mpenning@typo ~]$ EDIT If I use last -i mpenning, I see entries like this... mpenning pts/19 0.0.0.0 Fri Nov 16 10:32 - 10:35 (00:03) mpenning pts/17 0.0.0.0 Fri Nov 16 10:21 - 10:42 (00:21)

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  • How should I use my new SSD drive?

    - by jasondavis
    I just built a new PC the other day. Specs... Processor: Intel i7-930 quad core CPU CPU Cooler: COOLER MASTER Hyper 212 Motherboard: AsRock X58 Extreme 3 RAM/Memory: 6gb G-Skill tripple channel DDR3 memory (3 sticks of 2gb planning to get another kit to make it 12gb total soon) Operating System Hard drive: Intel X25-M 80GB Mainstream SATA2 Solid State Drive Video Cards: 2 XFX ATI Redeon HD 4650 cards to run 3-4 monitors Case: Lian Li PC-B10 Midtower case Power Supply: Antec TruePower New TP-750 Blue 750W Operating System Windows 7 Pro 64bit Not sure if the specs are helpful at all but I posted them just in case. So I got everything put together and running great so far but I need some advice/ideas/help/tips. I got the SSD drive in hopes of using it strictly for my windows 7 install along with all my other programs I install. I am then going to get another drive or 2 just for data (video,music,photos, etc). So my plan is to just install the new data drives and then in windows 7 I will change my "My documents" "My Music" "My Video" "MY Photos" library's to be located on the data drives instead of the OS SSD drive. I would ultimately like to install all my programs with my windows install on the SSD drive and then create an IMAGE of the drive and then 6 months down the road if things are sluggish I can just wipe the drive and restore my IMAGE with all my programs and settings in tact still. So here are some questions now. 1) How can I verify that TRIM is working on my new SSD? 2) Is there anything above that I missed that I should be doing? I think I once read that there is a page file or some sort of file that windows changes a lot and that it should be moved off f an SSD an onto my data drives. DOes anyone know what I might of heard? If you do can you explain the pros and cons of doing such a thing as well as how to possibly? 3) Any tips or advice to get the best performance from all this, I built a pretty nice system and I just want to make it stay that way as long as I can.

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  • What the best way to achieve RPO of zero and lowest possible RTO (less than 15 minutes) with SQL 2008 R2?

    - by Adrian Hope-Bailie
    We are running a payments (EFT transaction processing) application which is processing high volumes of transactions 24/7 and are currently investigating a better way of doing DB replication to our disaster recovery site. Our current and previous strategies have included using both DoubleTake and Redgate to replicate data to a warm stand-by. DoubleTake is the supported solution from the payments software vendor however their (DoubleTake's) support in South Africa is very poor. We had a few issues and simply couldn't ever resolve them so we had to give up on DoubleTake. We have been using Redgate to manually read the data from the primary site (via queries) and write to the DR site but this is: A bad solution Getting the software vendor hot and bothered whenever we have support issues as it has a tendency to interfere with the payment application which is very DB intensive. We recently upgraded the whole system to run on SQL 2008 R2 Enterprise which means we should probably be looking at using some of the built-in replication features. The server has 2 fairly large databases with a mixture of tables containing highly volatile transactional data and pretty static configuration data. Replication would be done over a WAN link to a separate physical site and needs to achieve the following objectives. RPO: Zero loss - This is transactional data with financial impact so we can't lose anything. RTO: Tending to zero - The business depends on our ability to process transactions every minute we are down we are losing money I have looked at a few of the other questions/answers but none meet our case exactly: SQL Server 2008 failover strategy - Log shipping or replication? How to achieve the following RTO & RPO with logshipping only using SQL Server? What is the best of two approaches to achieve DB Replication? My current thinking is that we should use mirroring but I am concerned that for RPO:0 we will need to do delayed commits and this could impact the performance of the primary DB which is not an option. Our current DR process is to: Stop incoming traffic to the primary site and allow all in-flight transaction to complete. Allow the replication to DR to complete. Change network routing to route to DR site. Start all applications and services on the secondary site (Ideally we can change this to a warmer stand-by whereby the applications are already running but not processing any transactions). In other words the DR database needs to, as quickly as possible, catch up with primary and be ready for processing as the new primary. We would then need to be able to reverse this when we are ready to switch back. Is there a better option than mirroring (should we be doing log-shipping too) and can anyone suggest other considerations that we should keep in mind?

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  • How to get the best LINPACK result and conquer the Top500?

    - by knweiss
    Given a large Linux HPC cluster with hundreds/thousands of nodes. What are your best practices to get the best possible LINPACK benchmark (HPL) result to submit for the Top500 supercomputer list? To give you an idea what kind of answers I would appreciate here are some sub-questions (with links): How to you tune the parameters (N, NB, P, Q, memory-alignment, etc) for the HPL.dat file (without spending too much time trying each possible permutation - esp with large problem sizes N)? Are there any Top500 submission rules to be aware of? What is allowed, what isn't? Which MPI product, which version? Does it make a difference? Any special host order in your MPI machine file? Do you use CPU pinning? How to you configure your interconnect? Which interconnect? Which BLAS package do you use for which CPU model? (Intel MKL, AMD ACML, GotoBLAS2, etc.) How do you prepare for the big run (on all nodes)? Start with small runs on a subset of nodes and then scale up? Is it really necessary to run LINPACK with a big run on all of the nodes (or is extrapolation allowed)? How do you optimize for the latest Intel/AMD CPUs? Hyperthreading? NUMA? Is it worth it to recompile the software stack or do you use precompiled binaries? Which settings? Which compiler optimizations, which compiler? (What about profile-based compilation?) How to get the best result given only a limited amount of time to do the benchmark run? (You can block a huge cluster forever) How do you prepare the individual nodes (stopping system daemons, freeing memory, etc)? How do you deal with hardware faults (ruining a huge run)? Are there any must-read documents or websites about this topic? E.g. I would love to hear about some background stories of some of the current Top500 systems and how they did their LINPACK benchmark. I deliberately don't want to mention concrete hardware details or discuss hardware recommendations because I don't want to limit the answers. However, feel free to mention hints e.g. for specific CPU models.

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  • How to encrypt dual boot windows 7 and xp (bitlocker, truecrypt combo?) on sdd (recommended?)

    - by therobyouknow
    I would like to setup a dual boot Windows 7 and Windows XP laptop/notebook computer where each operation system's partition is fully encrypted. I would like to do this on a SSD - a 128Gb Crucial M4. My research Dual boot of truecrypt encrypted OSs on one drive (not possible - in Truecript 7.x at time of writing) This cannot be done on a standard Truecrypt setup - it will only support encrypting one of the operating systems. I have tried this and also read about it here on superuser.com However, I did see a solution here that uses grub4dos as the initial bootloader to chain to separate truecrypt encrypted OSs, in my case Windows 7 and Windows XP: http://yyzyyz.blogspot.co.uk/2010/06/truecrypt-how-to-encrypt-multiple.html I am not going to consider this solution as it relies upon some custom code for use in the bootloader that is provided by the author. I would prefer a solution that can be fully understood so that I can be sure that there is nothing undesirable occuring (i.e. malware or just simply bugs in the code). I would like to believe such a solution doesn't have those risks but I can't be sure. BitLocker and Truecrypt combination - possible solution? So I am now considering a combination of encryption programs: I now aim to encrypt Windows XP with Truecrypt and Windows 7 with BitLocker. Assuming Truecrypt bootloader can boot into non-Truecrypt OSs (e.g. via hitting Escape to go to another menu), then this solution may be viable. SSDs and Encryption (use fastest possible spinning hard disk instead (?)) I read on various superuser.com posts and elsewhere that current SSDs are not suited to whole drive encryption for various reasons: impact of performance algorithms that give SSDs advantage over spinning harddisks. Algorithms used in compression of data for example. Wear on the SSD, shortening its life Security issues whereby data is repeated, as indicated in some Truecrypt documentation So I am now considering not using SSD. But with the aim to have the fastest drive possible, I am considering using the Western Digital Scorpion black 2.5" 7200rpm harddisk as this appears to be top rated among spinning platter-based harddrives (don't work for Western Digital). Summary So to achieve whole drive encrypted dual boot Windows 7 and Windows XP with minimal performance impact I intend to use a combination of Truecrypt and Bitlocker on a top-rated conventional spinning platter-based harddisk. Questions Will my summary: achieve whole disk encryption of the dual-boot Windows XP, Windows 7? OR an you suggest a simpler solution, including one that only requires only Truecrypt (BitLocker not available on XP). Or another encryption tool, including paid-for? provide the highest performance. Am I correct to avoid using SDD with encryption for the reasons I discovered? Are the concerns about SSDs and encryption still very real (some articles I read go back to 2010) Thanks for your input!

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  • Multiple OS's and GRUB chainloading

    - by Kent
    Hi, I want to have multiple OS installations and I have been advised that chain loading using GRUB is a good way to handle this. I have looked at tutorials on the web but I still have some questions before I can start. I want: Windows XP: 20 GB. For running some school stuff and a game which does not work through WINE. Xubuntu 9.04: 85 GB. My main OS. Another Linux distribution: 15 GB . For experimenting and trying Linux distributions out. I will: Wipe and install various distributions quite often on the 15 Use dd to make a copy of my Windows partition after installing it and getting things to work as I like. My experience is that Windows needs to be re-installed maybe once per year to not get bloated and slow. I have been told: To use GRUB chain loading. It will make it easier when kernel upgrades are made in the Linux distributions, as they modify the GRUB boot-menu. To my understanding I need to: (I might very well be mistaken) Install Windows first. Then install Xubuntu and let it write over the MBR with GRUB (I guess this is the default). Get the GRUB on the MBR start Windows XP if I want to (it's done by default), start Xubuntu using the kernel of my choice or defer execution to the boot sector of my other Linux distribution. The actual chain loading will only occur when I want to start my experimental install of Linux. I wonder: Is step 3 above correct and a good way to handle this? Is it also a good way to use chain-loading for both Xubuntu and my experimental Linux installation? How do I get a Linux distribution to install the boot loader it comes with to the boot sector of its partition and not to the MBR? If I can't get it to not touch the MBR. Then I could make a backup of the MBR using dd and then write it back after installing my experimental Linux installation. But then, how would I get the boot loader (lets say GRUB) into the boot sector of the experimental Linux installation? How would it work if said Linux installation gets a new kernel update and needs to update the GRUB menu?

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  • SSH Connection Refused - Debug using Recovery Console

    - by olrehm
    Hey everyone, I have found a ton of questions answered about debugging why one cannot connect via SSH, but they all seem to require that you can still access the system - or say that without that nothing can be done. In my case, I cannot access the system directly, but I do have access to the filesystem using a recovery console. So this is the situation: My provider made some kernel update today and in the process also rebooted my server. For some reason, I cannot connect via SSH anymore, but instead get a ssh: connect to host mydomain.de port 22: Connection refused I do not know whether sshd is just not running, or whether something (e.g. iptables) blocks my ssh connection attempts. I looked at the logfiles, none of the files in /var/log contain any mentioning on ssh, and /var/log/auth.log is empty. Before the kernel update, I could log in just fine and used certificates so that I would not need a password everytime I connect from my local machine. What I tried so far: I looked in /etc/rc*.d/ for a link to the /etc/init.d/ssh script and found none. So I am expecting that sshd is not started properly on boot. Since I cannot run any programs in my system, I cannot use update-rc to change this. I tried to make a link manually using ln -s /etc/init.d/ssh /etc/rc6.d/K09sshd and restarted the server - this did not fix the problem. I do not know wether it is at all possible to do it like this and whether it is correct to create it in rc6.d and whether the K09 is correct. I just copied that from apache. I also tried to change my /etc/iptables.rules file to allow everything: # Generated by iptables-save v1.4.0 on Thu Dec 10 18:05:32 2009 *mangle :PREROUTING ACCEPT [7468813:1758703692] :INPUT ACCEPT [7468810:1758703548] :FORWARD ACCEPT [3:144] :OUTPUT ACCEPT [7935930:3682829426] :POSTROUTING ACCEPT [7935933:3682829570] COMMIT # Completed on Thu Dec 10 18:05:32 2009 # Generated by iptables-save v1.4.0 on Thu Dec 10 18:05:32 2009 *filter :INPUT ACCEPT [7339662:1665166559] :FORWARD ACCEPT [3:144] :OUTPUT ACCEPT [7935930:3682829426] -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m tcp --dport 25 -j ACCEPT -A INPUT -p tcp -m tcp --dport 993 -j ACCEPT -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m tcp --dport 143 -j ACCEPT -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT -A INPUT -p tcp --dport 8080 -s localhost -j ACCEPT -A INPUT -m limit --limit 5/min -j LOG --log-prefix "iptables denied: " --log-level 7 -A INPUT -j ACCEPT -A FORWARD -j ACCEPT -A OUTPUT -j ACCEPT COMMIT # Completed on Thu Dec 10 18:05:32 2009 # Generated by iptables-save v1.4.0 on Thu Dec 10 18:05:32 2009 *nat :PREROUTING ACCEPT [101662:5379853] :POSTROUTING ACCEPT [393275:25394346] :OUTPUT ACCEPT [393273:25394250] COMMIT # Completed on Thu Dec 10 18:05:32 2009 I am not sure this is done correctly or has any effect at all. I also did not find any mentioning of iptables in any file in /var/log. So what else can I do? Thank you for your help.

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  • Squid on windows loadbalancing only to one server

    - by Martin L.
    After thousands of googles and trying days i cant get the load balancer/failover in squid on windows to work. Iam using squid 2.7. My webservers are 2 single NIC lighttpd and one dual nic lighttpd. server1 in this example is running squid on port 80 and lighttpd on port 8080 (just to test) Requirements: All 3 webservers running lighttpd should be balanced two option for load balancing: Best would be if server1 is busy server2 takes over, if server2 is busy server3 takes over, etc.. Round robin style evenly distributed load. Eg server1 takes first call, server2 second etc.. All requests should be treated the same way (no url rewriting or so on) Sent host headers have to be redirected to every server as http host header, speaking of "server1", "server1.company.internal" and "10.211.1.1". My approach: acl all src all acl manager proto cache_object http_port 80 accel defaultsite=server1.company.internal vhost #reverse proxy entries cache_peer 10.211.2.1 parent 8080 0 no-query originserver round-robin login=PASS name=server1_nic1 cache_peer 10.211.1.2 parent 80 0 no-query originserver round-robin login=PASS name=server2_nic1 cache_peer 10.211.2.3 parent 8080 0 no-query originserver round-robin login=PASS name=server3_nic1 cache_peer 10.211.2.4 parent 8080 0 no-query originserver round-robin login=PASS name=server3_nic2 #decl of names of squid host acl registered_name_hostdomain dstdomain server1.company.internal acl registered_name_host dstdomain server1 #ip of squid host acl registered_name_ip dstdomain 10.211.2.1 # access: redirects the correct squid hostname http_access allow registered_name_hostdomain http_access allow registered_name_host http_access allow registered_name_ip http_access deny all cache_peer_access server1_nic1 allow registered_name_hostdomain cache_peer_access server1_nic1 allow registered_name_host cache_peer_access server1_nic1 allow registered_name_ip cache_peer_access server2_nic1 allow registered_name_hostdomain cache_peer_access server2_nic1 allow registered_name_host cache_peer_access server2_nic1 allow registered_name_ip cache_peer_access server3_nic1 allow registered_name_hostdomain cache_peer_access server3_nic1 allow registered_name_host cache_peer_access server3_nic1 allow registered_name_ip cache_peer_access server3_nic2 allow registered_name_hostdomain cache_peer_access server3_nic2 allow registered_name_host cache_peer_access server3_nic2 allow registered_name_ip cache_peer_access server1_nic1 deny all cache_peer_access server2_nic1 deny all cache_peer_access server3_nic1 deny all cache_peer_access server3_nic2 deny all never_direct allow all Problems: Load balancer does not load balance other than to first server. Only if the first server is killed in any way the second will take over. I have seen the others working at some point, but definitely not as the intended load balancing described above. If the cache_peer_access is not defined sometimes the wrong hostname is sent to the backend webserver and this always depends on the defaultsite= parameter. Probably because the host header on the request to squid is not set and its replaced by defaultsite. Leaving out defaultsite didnt solve the problem. The only workaround i found for this is the current approach with cache_peer_access. Questions: Does the cache_peer_access influence the round-robin? Is there a better workaround to pass the host header to the backed webservers? Which parameters do increase the speed of load balancing or does anyone have a better approach? -Martin

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  • How did what appears to be a virus get on my computer? (explanation of situation enclosed)

    - by Massimo
    My system is Windows XP SP3, updated with the latest patches. The PC is connected to a Cisco 877 ADSL router, which does NAT from the internal network to its single static public IP address. There are no forwarded ports, and the router's management console can only be accessed from the inside. I was doing two things: working on a remote office machine via VPN and browsing some web pages on the Cisco web site. The remote network is absolutely safe (it's a lab network, four virtual servers, no publicly accessible services and no users at all; also, none of what I'm going to describe ever happened there). The Cisco web site... well, I suppose is quite safe, too. Suddenly, something happened. Strange popups appears anywhere; programs claiming they're "antimalware", "antispyware" et so on begins autoinstalling; fake Windows Update and Security Center icons pop up in the system tray. svchost.exe began crashing repeatedly. Then, finally, after some minutes of this... BSOD. And, upon rebooting, BSOD again. Even in safe mode. Ok, that was obviously some virus/trojan/whatever. I had to install a new copy of Windows on another partition to clean things up. I found strange executables, services and DLLs almost anywhere. Amongst the other things, user32.dll and ndis.sys had been replaced. A fake software called "Antimalware Doctor" had been installed. There were services with completely random names or even GUIDs (!), and also ones called "IpSect" and "Darkness". There were executable files without an .exe extension. There were even two boot-class drivers, which I'm quite sure are the ones that finally caused the system to crash. A true massacre. Ok, now the questions: What the hell was that?!? It was something more than a simple virus! How did it manage to attack my computer, as I am behind a firewall and was not doing anything even only potentially harmful on the web at the time?

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  • Alienware m15x (older model) BSOD investigation

    - by Crishu
    A frined of mine asked me to help him with an Alienware m15x laptop that had a little service history. It was bought in june 2008, serviced in january 2009 for a random fps drop problem, Alienware returned it saying nothing was wrong. The laptop still had hiccups, but after juggling a few drivers and settings, the fps drops weren't as noticeable. Eventually it died in Sept. 2009. It would not boot up locking itself on a white/gray screen. (i think it was overheating .. clocking in 100 degrees Celsius). So back to Alienware it went. They replaced the GPU and all was fine. Up until these blue screens started showing up. One other thing that was updated was the HDD and a Windows 7 reinstall, in August. From then on it seems to have started its BSOD. Could this be the culprit? Why? 0_o The original Windows was Vista but it was upgraded with a digital download/purchase of Windows 7 Home Premium and activated after installing windows. No errors on the old HDD, just on the latest installation. LE:Due note that now the old HDD is used to see if issues re-occur. So please, I am in need of someone who can interpret these windows dump files: Minidump I may have come to some conflicting conclusions. So if someone can clarify each dump/date and the probable cause/error it had; and a final conclusion or solution, we would be very grateful. Also please consult report for other system info I omitted: same link,code: XRWIVLWG If I missed something or if you have any other questions I'll be happy to answer them. Thank you. Good day. Processor: Intel(R) Core(TM)2 Duo CPU T9300 @ 2.50GHz Network Adapter Properties: Broadcom NetLink (TM) Gigabit Ethernet Intel(R) Wireless WiFi Link 4965AGN Video Adapter Properties: Driver Description NVIDIA GeForce 8800M GTX Driver Date 19.08.2009 Driver Version 8.16.11.8681 Driver Provider NVIDIA INF File oem19.inf Hardware ID PCI\VEN_10DE&DEV_060C&SUBSYS_0770152D&REV_A2 Location Information @system32\DRIVERS\pci.sys,#65536;PCI bus %1, device %2, function %3;(1,0,0) PCI Device NVIDIA GeForce 8800M GTX [NoDB] BIOS String Version 62.92.34.0.8 Installed Drivers nvd3dum (8.16.11.8681), nvwgf2um, nvwgf2um Hard Dik Drive: Model ID ST9120823ASG (**older one 120gb**) Model ID WD32000BEKT (new 320gb with fresh OS)

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  • Can you set up a gaming LAN using OpenVPN installed in a VMware guest OS and be playing the game on the host OS?

    - by Coder
    I would like to setup a gaming VPN. Ie. I have some games that work over LAN and would like to play them with people that are not on my LAN. I know I can do this with OpenVPN. My ultimate goal would be to run OpenVPN portably on my host OS and not even need any virtualization. As such i don't want to install it on my host, but i'm fine with running it portably. I'm even fine with temporarily adding registry keys, and then running a .reg file to remove these entries once i'm done. To this effect i have installed OpenVPN on a virtual machine and diffed the registry. I then manually (using a .reg file) added all the keys that seem important on my host OS and copied the installation folder of OpenVPN onto my host machine. Then i try to run openVPN GUI 1.0.3 as a test and it says "Error opening registy for reading (HKLM\SOFTWARE\OpenVPN). OpenVPN is probably not installed". I verified that that key is indeed in the registry with all subkeys and it looks correct. I have tried running the GUI as an administrator and in compatibility mode with no success. I am running Windows 7. If this fails then i would be happy with installing OpenVPN on a virtual machine in VMWare but they key is that i will be running the game installed on my host machine. The first question for this option is if this is even possible. The second is, that I can't get the VM to have internet access if I use bridging but i can if i use NAT. Is it possible to do this game VPN setup with VMWare guest OS running using NAT? Summary of questions: -Is it possible to run openVPN portably and if so what did i miss above? -If it's not possible to run it portably, then can setup a gaming LAN by installing OpenVPN in a guest OS with NAT and how can i do this? -If the above is not possible then can i install OpenVPN in a guest using bridging and if so how can i set this up with a Windows 7 host and Windows XP guest as currently i can't get the guest to be able to access the internet in bridging mode, but it working in NAT mode. -In general is there any good documentation on setting up a gaming LAN with OpenVPN (i am using 2.1.4) as i have never set up a VPN of any sort before so any help would be much appreciated. Thanks!

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  • Rails /tmp/cache/assets permissions issue using Debian virtual machine hosted on OS X Lion

    - by Jim
    I am running Parallels Desktop 7 on OS X Lion. I have a VM with Debian installed, and inside that VM I setup a Rails development environment. I am using Parallels Tools to share out my OS X home directory to the VM - the goal here is to run the Rails server on the VM, but host the files on OS X (so they are automatically backed up, and so I can use tools like Textmate to develop with). Everything seems to work with the shared directory - my Debian user can read, write, and execute files. However, when I cloned a recent Rails project from Git, I got an error message when it tried to compile the CSS assets. My symptoms are exactly the same as in the question: http://stackoverflow.com/questions/7556774/rails-sprocket-error-compiling-css-assest-chown-issue I believe this is permissions-based, but it is really weird. My entire Rails project directory has permissions set to 777 and my Debian user owns it. If I navigate into /tmp/cache/assets, those permissions are the same. However, the three-character directories Rails is creating (DCE, DA1, D05, etc...) are being created without write permissions! If I refresh the Rails page a few times, about 4 or 5 (with Rails creating new three-character directories every time), eventually it will create one of the directories with the proper 777 permissions and everything will work! This will persist until I make a change to the CSS files and it has to recompile. Does anyone have any idea what might be going on here? I can't fathom why it is creating temp directories with incorrect permissions, or why after a few refreshes the good permissions kick in and it works... It definitely seems to be an issue with the share, since if I move the project into a different directory on the VM, it seems to work fine. On the OS X side, I've given the shared folder 777 permissions as well, but no dice...any ideas? Update I've found that the number of times I need to refresh before it works is not random - it has to do with how many assets are being compiled. For example, if I edit one of my CSS files, and there are four CSS files in the app/assets/stylesheets directory, I have to refresh four times before the app will finally work without the operation not permitted error...

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  • Anti-virus protection question?

    - by DaBaer
    About 4 years ago, I found Kaspersky and have been using the most current version since. Most people try and argue the use of AVG or Avast to me, and there are some very solid reasons I do not go that route. Over the years, I have found Kasp to become bulkier and bulkier, and have had issues setting it up for friends/family/clients. I am just curios on possible recommendations from other users, with my criteria in mind: What I like about Kasp in the past: The license sold in stores in a 3 pack, is considered a commercial license, and emails from Kasp in response to my questions, make it clear that I can do with the 3 licenses that I want, providing I do not use more than 3 installs per Key. So, allowed me to buy 3, 5, and 7 packs, and resell to users at a cheaper cost than what they would pay if they bought their own license. The ability to easily obtain a currently updated .exe for installation on multiple peoples machines. Power of the scan. Kasp has been a good solution for me (even when using a trial license) on cleaning up machines that were badly infected (in which AVG and AVAST were unable to.) Speed of install/update. After a cleanup of malwarebytes, spybot, mcafee stinger, ccleaner, and combofix, I used to be able to get Kasp Int Security installed and updated in around 5 minutes. The issues that I have with the free AV, is strength of protection. In my opinion for someone who is a 'power use' these are good alternatives, because such a user should be trained or knowledgeable enough to be careful and not get themselves in trouble. Most of the users I assist, are too PC ignorant to know any better, and go hogwild on the web. It has been my experience that the number of people coming back to me with spyware/malware/virus issues since I have converted from AVG to Kasp has been cut down to around 20% of what it used to be 4 or 5 years ago. In a perfect world, I could install and use Kasp Internet Security 2008, and be very happy. But this is not the case anymore. So after this long description of what I used, and have used, does anyone have any good recommendations on AV that isn't going to cost me too much per install?

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  • Which hardware to VM ratio for Build-Server virtualization?

    - by Martin
    Let's start with saying that I'm a total noob wrt. to server virtualization. That is, I use VMs often during development, but they're simple desktop machine things for me. Now to my problem: We have two (physical) build servers, one master, one slave running Jenkins to do daily tasks and build (Visual C++ Builds) our release packages for our software. As such these machines are critical to our company, because we do lot's releases and without a controlled environment to create them, we can't ship fixes. (And currently there's no proper backup of these machines in place, because they do not hold any data as such - it just would be a major pain to setup them again should they go bust. (But setting up backup that I'd know would work in case of HW failure would even be more pain, so we have skipped that until now.)) Therefore (and for scaling purposes) we would like to go virtual with these machines. Outsourcing to the cloud is not an option, not at all, so we'll have to use on-premises hardware and VM hosts. Each Build-Server (master or slave) is a fully configured (installs, licenses, shares in case of the master, ...) Windows Server box. I would now ideally like to just convert the (two) existing physical nodes to VM images and run them. Later add more VM slave instances as clones of the existing ones. And here begin my questions: Should I go for one VM per one hardware-box or should I go for something where a single hardware runs multiple VMs? That would mean a single point of failure hardware wise and doesn't seem like a good idea ... or?? Since we're doing C++ compilation with Visual Studio, I assume that during a build the hardware (processor cores + disk) will be fully utilized, so going with more than one build-node per hardware doesn't seem to make much sense?? Wrt. to hardware options, does it make any difference which VM software we use (VMWare, MS, Virtualbox, ... ?) (We're using Windows exclusively for our builds.) Regarding budget: We have a normal small company (20 developers) budget for this. ;-) That is, if it's going to cost a few k$ it's going to cost. If it's free - the better. I strongly prefer solutions where there's no multi-k$ maintenance costs per year.

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  • What Sort of Server Setup Am I Likely to Need? - School A/V streaming

    - by DeathMagus
    My prior experience with servers has generally been limited to home file-sharing servers, low-traffic web-servers, and the like. This leaves me with the technical knowledge of how to set up a system, but little experience in terms of scaling said system. My current project, however, has me as the technical lead in setting up a school for online audio and video streaming. The difficulty I'm running into is that I don't quite have the experience to guess what they'll need, and they don't have the experience to tell me - so I've tried to ask as many pertinent questions about what they want to do with their server, and here's what I found out: About 1000 simultaneous users, and hoping to expand (possibly significantly) Both video and audio streaming, at obviously the highest quality possible Support for both live and playlist-based streaming. Probably only one channel, but as it's an educational opportunity, I imagine letting them have a few more wouldn't hurt. No word on whether they're locked into Windows or whether Linux is acceptable. Approximate budget - $7000. It may actually be about $2k less than this, because of a mishap with another technology firm (they ordered a $7000 DV tape deck for some reason, and now the company wants them to pay a 30% restocking fee). The tentative decisions I've already made: I'm planning on using Icecast 2 for my streaming server, fed by VLC Shoutcast encoding. Since the school already has a DMZ set up, I plan on placing the Icecast server in there, and feeding it through their intranet from a simple workstation computer in their studios. This system isn't in any way mission critical - it's an education tool (they're a media magnet school), so I figure redundancy is not worthwhile to them from a cost:benefit perspective. What I don't know is this: How powerful of a server will I need? What is likely to be my major throttle - bandwidth? How can I mitigate that? Will I need anything special for the encoding workstation other than professional video and audio capture cards and a copy of VLC? Are there any other considerations that I'm simply missing? Thanks a lot for any help - if there's more information you need, let me know and I'll tell you all I can.

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  • Is this iptables NAT exploitable from the external side?

    - by Karma Fusebox
    Could you please have a short look on this simple iptables/NAT-Setup, I believe it has a fairly serious security issue (due to being too simple). On this network there is one internet-connected machine (running Debian Squeeze/2.6.32-5 with iptables 1.4.8) acting as NAT/Gateway for the handful of clients in 192.168/24. The machine has two NICs: eth0: internet-faced eth1: LAN-faced, 192.168.0.1, the default GW for 192.168/24 Routing table is two-NICs-default without manual changes: Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 (externalNet) 0.0.0.0 255.255.252.0 U 0 0 0 eth0 0.0.0.0 (externalGW) 0.0.0.0 UG 0 0 0 eth0 The NAT is then enabled only and merely by these actions, there are no more iptables rules: echo 1 > /proc/sys/net/ipv4/ip_forward /sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # (all iptables policies are ACCEPT) This does the job, but I miss several things here which I believe could be a security issue: there is no restriction about allowed source interfaces or source networks at all there is no firewalling part such as: (set policies to DROP) /sbin/iptables -A FORWARD -i eth0 -o eth1 -m state --state RELATED,ESTABLISHED -j ACCEPT /sbin/iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT And thus, the questions of my sleepless nights are: Is this NAT-service available to anyone in the world who sets this machine as his default gateway? I'd say yes it is, because there is nothing indicating that an incoming external connection (via eth0) should be handled any different than an incoming internal connection (via eth1) as long as the output-interface is eth0 - and routing-wise that holds true for both external und internal clients that want to access the internet. So if I am right, anyone could use this machine as open proxy by having his packets NATted here. So please tell me if that's right or why it is not. As a "hotfix" I have added a "-s 192.168.0.0/24" option to the NAT-starting command. I would like to know if not using this option was indeed a security issue or just irrelevant thanks to some mechanism I am not aware of. As the policies are all ACCEPT, there is currently no restriction on forwarding eth1 to eth0 (internal to external). But what are the effective implications of currently NOT having the restriction that only RELATED and ESTABLISHED states are forwarded from eth0 to eth1 (external to internal)? In other words, should I rather change the policies to DROP and apply the two "firewalling" rules I mentioned above or is the lack of them not affecting security? Thanks for clarification!

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