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• Problem with ubuntu 10.10 running from USB drive

  - by Surjya Narayana Padhi

  Hi Geeks, I recently downloaded Ubuntu 10.10 and created an USB drive with that. I started to run the Ubuntu from that USB drive. But I am facing so much problem. I am thinking why its not so much easy like Windows to do all my job in ubuntu. Always I get some error message or to install something. This time I am getting the following errors. I am trying to download and install Aircrack-ng. So used the command sudo apt-get install aircrack-ng. But the installation stops with the following error : update-initramfs: deferring update (trigger activated) cp: cannot stat `/vmlinuz': No such file or directory dpkg: error processing bcmwl-kernel-source (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: initramfs-tools bcmwl-kernel-source E: Sub-process /usr/bin/dpkg returned an error code (1) I don't even have the aptitude command installed till now. Are all these errors because of I am running the ubuntu from USB drive? Is there any simple and easy way to go to Ubuntu Software Center and download all the required essentials at one shot and then Aircrack-ng? I could not find the Aircrack-ng in Ubuntu Software Center Can anybody give me detail steps to solve all my problems above. I am frustrated searching for updates and installations. When something works and something does not work. Can anybody suggest me how I should proceed after installing ubuntu to run on a USB drive. So that I can use the OS like Windows. Like software download,wireless driver, sound, video, documents, C:, D: all things should be there. Please somebody help.

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• Postfix : outgoing mail in TLS for a specific domain

  - by vercetty92

  I am trying to configure postfix to send mail in TLS (starttls in fact), but only for a specific destination. I tried with "smtp_tls_policy_maps". This is the only line in my main.cf file regarding TLS configuration, but it seems not working. Here is my main.cf file: queue_directory = /opt/csw/var/spool/postfix command_directory = /opt/csw/sbin daemon_directory = /opt/csw/libexec/postfix html_directory = /opt/csw/share/doc/postfix/html manpage_directory = /opt/csw/share/man sample_directory = /opt/csw/share/doc/postfix/samples readme_directory = /opt/csw/share/doc/postfix/README_FILES mail_spool_directory = /var/spool/mail sendmail_path = /opt/csw/sbin/sendmail newaliases_path = /opt/csw/bin/newaliases mailq_path = /opt/csw/bin/mailq mail_owner = postfix setgid_group = postdrop mydomain = ullink.net myorigin = $myhostname mydestination = $myhostname, localhost.$mydomain, localhost masquerade_domains = vercetty92.net alias_maps = dbm:/etc/opt/csw/postfix/aliases alias_database = dbm:/etc/opt/csw/postfix/aliases transport_maps = dbm:/etc/opt/csw/postfix/transport smtp_tls_policy_maps = dbm:/etc/opt/csw/postfix/tls_policy inet_interfaces = all unknown_local_recipient_reject_code = 550 relayhost = smtpd_banner = $myhostname ESMTP $mail_name debug_peer_level = 2 debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin xxgdb $daemon_directory/$process_name $process_id & sleep 5 And here is my "tls_policy" file: gmail.com encrypt protocols=SSLv3:TLSv1 ciphers=high I also tried gmail.com encrypt My wish is to use TLS only for the gmail domain. With this configuration, I don't see any TLS line in the source of the mail. But if I tell postfix to use TLS if possible for all destination with this line, it works: smtp_tls_security_level = may Beause I can see this line in the source of my mail: (version=TLSv1/SSLv3 cipher=OTHER); But I don't want to try to use TLS for the others domains...only for gmail... Do I miss something in my conf? (I also try whith "hash:/etc/opt/csw/postfix/tls_policy", and it's the same) Thanks a lot in advance

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• Linux CentOS strange memory readings

  - by user2008937

  I am actually a young junior sys admin. I have a question - i am trying to understand how linux deals with memory... while playing around different monitoring programs I found some strange thing. When I run top on my laptop it shows me that FIREFOX process with pid 8778 takes 18,3% of memory (%MEM column). grep "MemTotal" /proc/meminfo Above command give me 1848336kb/1024 = 1805megs of memory (its ok - i have 2 gigs of ram). So if the firefox process takes 18,3% of MEM(according to tops %MEM column) then it takes 0.183 * 1805 which is approximately 325mb of memory. Quite a lot as for firefox... But well, in Linux there are lots of shared libraries that programs commonly uses (like famous libc). And those libraries are added to memory utilization of every process that uses it in the system, despite they are actually reading same file(single object in memory). So top may show too big mem utilization because of those shared libraries. Well, it is time to use PMAP which should show us the real mem utilization of process. But.. pmap -d $(pidof firefox) mapped: 983460K writeable/private: 757164K shared: 66416K so pmap shows that 983460/1024=993MB of memory is mapped to this process. It is in fact much bigger than mem utilization showed by top. Whats wrong here? How pmap can show more than top? even when top adds also the shared libraries (which in fact are single objects in memory) for each process that uses it? and pmap omits it? Regards Krzysztof

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• KVM and libvirt: How to configure a new disc device to an existing VM?

  - by initall

  I've got an Ubuntu 9.04 server running two VM's. In /etc/libvirt/qemu/machine1.xml two disk devices are defined like this: <devices> <emulator>/usr/bin/kvm</emulator> <disk type='file' device='disk'> <source file='/vserver/machine1/disk0.qcow2'/> <target dev='hda' bus='ide'/> </disk> <disk type='file' device='disk'> <source file='/vserver/machine1/disk1.qcow2'/> <target dev='hdb' bus='ide'/> </disk> I need more storage space in at least one of the devices and thought about adding a third hdc device by simply adding one with same style as above and re-organising my mount structure (The virtual sizes of the current qcow2 files are unfortunately limited.) My problem is that reloading libvirtd and restarting the VM do not result in a new visible device (checked with fdisk). I'm aware of extending an existing qcow2 file (converting to raw format, cat-ing/adding the new one, using smth. like gparted) - but only as a last resort. Hopefully it's something very simple I'm missing?

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• iptables firewall rules not allowing ssh from lan to DMZ

  - by ageis23

  Chain INPUT (policy ACCEPT) target prot opt source destination REJECT tcp -- anywhere anywhere tcp dpt:www reject-with tcp-reset REJECT tcp -- anywhere anywhere tcp dpt:telnet reject-with tcp-reset ACCEPT 0 -- anywhere anywhere state RELATED,ESTABLISHED DROP udp -- anywhere anywhere udp dpt:route DROP udp -- anywhere anywhere udp dpt:route ACCEPT udp -- anywhere anywhere udp dpt:route logdrop icmp -- anywhere anywhere logdrop igmp -- anywhere anywhere ACCEPT udp -- anywhere anywhere udp dpt:5060 ACCEPT 0 -- anywhere anywhere state NEW logaccept 0 -- anywhere anywhere state NEW ACCEPT 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere logdrop 0 -- anywhere anywhere Chain FORWARD (policy ACCEPT) target prot opt source destination REJECT 0 -- 192.168.0.0/24 192.168.2.0/24 reject-with icmp-port-unreachable ACCEPT tcp -- choister 192.168.2.142 tcp dpt:ssh state NEW REJECT 0 -- 192.168.0.0/24 192.168.3.0/24 reject-with icmp-port-unreachable ACCEPT gre -- 192.168.1.0/24 anywhere ACCEPT tcp -- 192.168.1.0/24 anywhere tcp dpt:1723 ACCEPT 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere TCPMSS tcp -- anywhere anywhere tcp flags:SYN,RST/SYN TCPMSS clamp to PMTU lan2wan 0 -- anywhere anywhere ACCEPT 0 -- anywhere anywhere state RELATED,ESTABLISHED logaccept tcp -- anywhere choister tcp dpt:www TRIGGER 0 -- anywhere anywhere TRIGGER type:in match:0 relate:0 trigger_out 0 -- anywhere anywhere logaccept 0 -- anywhere anywhere state NEW logdrop 0 -- anywhere anywhere The ssh server I'm trying to connect to is in the DMZ(192.168.0.145). It's mainly used as a web server. I need access to it from my room 192.168.2.142. I don't get why ssh can't forward onto the 192.168.2.0 subnet? I'm sure it's the reject rule that causing this because it works without it.

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• a brand new FS based on a database without using fuse

  - by Devrim

  hi all, To serve millions of files out of a single directory, being able to connect to a drive from hundreds of endpoints, and for some other reasons (to avoid gluster/nfs/all fs based networking solutions), I want to evaluate the possibility of making a filesystem that's based on a mongodb (or any other). Basically, it works like fusefs, every single file is kept in mongo gridfs. In theory, I do, mount mongodbfs /mountPoint mongodb://localhost then when i say touch /mountPoint/test.txt this file is inserted into mongodb. This FS will also store uid/gid and perms with the file, we can throw hundreds of servers to it, and no useradd will be necessary. I'm not thinking to include all the features of FS, just the ones we need. My question is, how do I start my quest in finding resources, books, links, people, developers who'd help me implement this? at least a proof of concept. Is it feasible? What should I expect as a timeline for such undertaking? Please only think about gazillion small files and folders.

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• Manual NAT on Checkpoint (Redirect all http requests to a local web server)

  - by kulakli

  Hi, We have a proxy server in internal network and I want to redirect all internet http requests to a web server in local network. It'll be like a Network Billboard that say "No direct connection is available. Set up your proxy etc." For example: A user starts the computer Opens the browser Trys to open www.google.com Should see web server output on local network Trys another web site on internet Should see web server output on local network Sets up proxy Trys to connect to a web site Web site should be loaded I have added a simple manual NAT rule to address translation in Checkpoint firewall but it simply does not work. Here is my address translation rule Source Destination Service T.Source T.Destination T.Service MY_PC A_GOOGLE_IP ALL ORIGINAL INT_WEB_SRV ORIGINAL Then when I ping A_GOOGLE_IP, replies come from INT_WEB_SRV, as I expected. However, when I try to connect A_GOOGLE_IP from browser (http://A_GOOGLE_IP), No replies come from SYN_SENT and falls into timeout. When I look at the firewall log of INT_WEB_SRV, I can see the incoming connection requests from MY_PC is accepted and NO denies. By the way, there is no problem to see INT_WEB_SRV (http://INT_WEB_SRV) from browser. My understanding is, my nat rule at checkpoint NGX R60 does not include return packets. I definitely need some help. Regards, Burak

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• VMware Workstation Bridged Network Host UnReachable

  - by user2097818

  VMware Workstation 7 on Win7-64 (Home Premium). I have confirmed this on any guest running on this machine (from winxp to debian). I am using a bridged network connection for my guests (Automatic on VMnet0). All of the network configuration is done with DHCP (including on the host). Problem What I can not do: Ping my host machine from inside any VM. (either shows me "Destination Host Unreachable" or will just timeout) What I CAN do right after power up, with no problems at all. I can connect to the internet from inside the VM I can ping my router from inside the VM I can ping other machines on my network from inside the VM Other machines can ping the VM Other machines can ping the host My host machine can ping the VM (this one is important. read further) Details So I have my router assigned as 192.168.2.1/255.255.255.0, and the router provides the DHCP service (and it seems to be doing so successfully). There are no IP conflicts on the network that I am aware of. All Gateways and Subnet masks are appropriate and matching. My entire workshop is on one single subnet, with one single DHCP server and gateway. There is one method in which I can ping successfully, but it requires an active connection initiated from the host (I start pinging from host to VM). During the period of the active connection, I can successfully ping from VM to host, using explicit IP address. As soon as the host connection is closed, the VM ping starts hanging with the same old messages. My Thoughts This really feels like a firewall problem, but I have turned off all firewalls on host and VM, powered down the network, powered back up, and the problem still persists. And if it was firewall, why would only the IP address associated with bridged VM networks be blocked. I feel as though my host operating system (Win7) is somehow configured incorrectly, or, VMware Workstation is configured incorrectly from the host side. Although I have done my best to put everything in default, I feel like I am missing something silly.

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• How do you avoid that server documentation gets out of sync with the actual setup?

  - by Frerich Raabe

  I'm a hobbyist maintaining a small FreeBSD server serving mail via IMAP - it's an exercise in server administration. The setup does have reasonably good documentation (in AsciiDoc format) which recently allowed another person to recreate the entire setup from scratch in less than 30 minutes. However, I noticed that after the initial setup, it easily happens that small changes done to the system (say: inetd gets disabbled, my IMAP server listens on an additional port for ManageSieve connections, a new router is added to the exim configuration) don't end up in the documentation immediately (if at all). My idea was to avoid this problem by (partially?) generating the documentation out of the configuration files and the comments therein - one way to implement this may be to put /etc and /usr/local/etc into some source code management system (say - git) and then run a script which regenerates the documentation on every commit. However, I'm not sure whether that would be overkill and/or too difficult to get right (after all, I don't want complete copies of the source files in my documentation but rather just the diffs). How do other people avoid that the server documentation gets outdated - is there a good way to keep them in sync automatically, or do you just have the discipline to update the documentation the same time you modify the system?

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• ATI Firepro v4800 3 monitor support

  - by Jared275

  I have an interesting, yet very frustrating problem. I have two computers, both running win7 32 bit, and both with ATI Firepro V4800 graphics cards. Both are using the DVI port and two DP to DVI adapters to connect 3 monitors. One of them is able to display three desktops, while the other fails at enabling the third, displaying "cannot save changes" in display properties while requiring that one monitor must be disabled when making the change in CCC. I've verified that both computers have the same driver version and that both are using the same DP-DVI adapters. This articles suggests a few things to try, but none of its suggestions seem to work either. I'm kind of at my wits end, hence my posting here. If this is not an appropriate question for SU, I apologize. I admit that I am not very familiar with the differences between dual link and single link DVI, and that is something I have not verified is standardized between the two computers. Is that a possible reason one is working and the other isn't? How do I check if the DVI cable is a single link, or dual link?

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• Ping with explicit next-hop selection (aka Monitoring multiple default gateways)

  - by Michuelnik

  I have a linux (debian) router with two internet connections (A) and (B). (A) is preferred, (B) is fallback. I want to monitor the internet connection (and not only the availability of the gateways!) and change the default route appropriately. If (A) is not providing internet, switch to (B) If (A) is providing internet again, switch back to (A). Only problem I have is in case (2). My routing table points towards a working internet so I cannot easily detect whether internet is working over link (A) again. I am search for a ping or traceroute (or other diagnosis-tool) which can select the next-hop explicitly. ping -r looks promising, but can only ping a host on the lan. (It only has to write another destination address in the packet, damnit!) traceroute -g gateway looks even more promising and nearly does what I want - but sets source routing options which my next-hops deny. (Not within my administrative boundary...) I just want a $ping, that can: select a source interface (and address) select a next-hop on that interface ping any arbitrary ip address I could do evil trickery with policy-based routing but that would have production impact for all users. I would like to see a side-effect-free solution....

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• organizing my music and my itunes

  - by Cawas

  What can we do to organize our music? I've got over 20k items on my iTunes Library, at least 5k with ratings and play counts, apparently just 12k music files and I can't understand how this question have not been properly answered yet. Maybe there is no answer. I have too many duplicates, broken links, bad music, corrupted files... Well, a big mess with no tags! Probably there's no single software capable of just organizing everything, though I'd love one. Hopefully some time in the near future we all will be able to just sync the cloud of our automagically selected music to the newly created offline copy. But meanwhile... Please, do consider I've at least gave a shot (even while not a full test drive) to every single answer linked here already, plus a few more. I'm fine with using other software (mac too, please) to organize, but I'd need it to sync (retrieve and put back) at least iTunes ratings, because of iPhone and smart playlists. Not looking for iTunes replacement. I'm hoping to hear what you hardcore music organizers out there are using as your own solutions! :) I myself am using way too many tools, getting way too little done and end up going song by song.

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• High speed network configuration

  - by Peter M

  Sorry if this seems to be a stupid question, I'm not sure how to specify what I want to know when checking google. I will have 2 or 3 devices pumping out data on a 100Base-T port. The combined data rate of all devices is about 15KB/S which exceeds the optimal 100Base-T channel capacity (12KB/S), but well within the realms of a 1000Base-T connection. Each device will be sending a burst of data in the form of an FTP transfer to a common, single host computer in a sequential manner ie: Device A establishes FTP connection and transfers data Device B establishes FTP connection and transfers data Device C establishes FTP connection and transfers data It may be that the A&B, B&C and C&A transfers overlap in the time domain to some extent. There will be minimal traffic going back from the computer to each device (in general what ever is needed to support the FTP transfers), and the network will be dedicated to transferring data between these devices and the host computer. Is it possible to use a switch to combine the multiple incoming 100Base-T streams into a single outgoing 1000Base-T stream? if so what features in a switch should I be looking for? Or would it be better to have 3 physical point-to-point 100Base-T dedicated connections between each device and the host computer? (thus having at least 3 physical Ethernet interfaces on that computer) Note that I can't change the interface on the devices, but I am free to choose the network and host computer configuration. Thanks for you help Peter

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• Internet setup for my office

  - by prakash

  We have two internet connections to our office and our current setup is like this.. The internet connections require pppoe log in so i take each cable and plug it into a wifi router and configure the router to log in to the pppoe and then plug in a cable from the router to a switch and distribute the internet throughout my office. The problem with this setup is it is really hard to monitor and im not able to monitor who is hogging internet usage and what he or she is actually using it for. apart from this we also have a nas setup which is routed through another switch . Could someone please throw a little light on how i can restructure this setup for easy monitoring and better transparency... ? each wan router is connected to a different switch and is distributed to users accordingly.. we have around 40 users in the office.. we want to setup a single linux box to which i want to connect the two wan connections and from there distribute it to all our users.... im looking for a solution where we do not have to invest more that buying a single pc and a couple of nics

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• Joomla performance problems on AWS

  - by Bobby Jack

  I'm running a site on AWS with the following setup: Single m1.small instance (web server) Single RDS m1.small db Joomla 1.5 Generally, the site is performant, but is fairly low-traffic - say around 50-100 visits / hour. However, at peak time, we see about double that traffic. During peak time, pretty much every day: CPU usage on the web server slowly climbs to 100% CPU usage on the RDS server climbs quite quickly to about 30%, from an average of about 15 Database connections shoot up to about 140, from a normal average of about 2 or 3 The site is then occasionally unreachable, certainly according to pingdom monitoring. Does anyone recognise this behaviour? Can you point me in the right direction to begin investigating? Of course, RDS makes it difficult to do things like slow query logging, so I've started by regularly dumping the mysql process list into a file to see if there's anything I can spot there, but it would be good to have something more concrete to investigate. UPDATE At least, can someone confirm that I'm definitely right in saying that the level of traffic implies the problem must be a specific type of query taking way longer than it should to execute? This would happen if a table gets locked, and many queries need to write to it, right? For this very reason, I've already changed the __session table type to InnoDB.

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• SSD as primary or secondary drive on a small Linux server?

  - by Alex Martelli

  I'm pensioning off my 10-years-old home server and replacing it with an Ubuntu 10.04 box. The two storage devices are a Western Digital Caviar Green 2.0TB HD and an Intel X25-M 34nm Gen 2 80GB SATA II 2.5inch SSD (the box has 8GB RAM and an i5 750, if it matters). I don't care much about boot times (since I don't plan to reboot all that often;-); the main frequent, performance-demanding task will be (re)building large open source C or C++ software packages from sources (as an open source contributor, I do that often). So, I thought I'd keep the SSD as the secondary drive and the HD as the primary one, using the SSD mostly for the files that can otherwise demand a lot of seeking (esp. in a parallel make). However, the friendly vendor (perhaps more experienced in Windows systems than in Linux ones) thinks the "normal" way to configure the machine would be with the SSD as the primary drive. I'm pretty rusty on configuring and tuning systems, so, I thought I'd better double check on SuperUser... thanks in advance for advice about this choice!

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• SQL Server Read Locking behavior

  - by Charles Bretana

  When SQL Server Books online says that "Shared (S) locks on a resource are released as soon as the read operation completes, unless the transaction isolation level is set to repeatable read or higher, or a locking hint is used to retain the shared (S) locks for the duration of the transaction." Assuming we're talking about a row-level lock, with no explicit transaction, at default isolation level (Read Committed), what does "read operation" refer to? The reading of a single row of data? The reading of a single 8k IO Page ? or until the the complete Select statement in which the lock was created has finished executing, no matter how many other rows are involved? NOTE: The reason I need to know this is we have a several second read-only select statement generated by a data layer web service, which creates page-level shared read locks, generating a deadlock due to conflicting with row-level exclusive update locks from a replication prcoess that keeps the server updated. The select statement is fairly large, with many sub-selects, and one DBA is proposing that we rewrite it to break it up into multiple smaller statements (shorter running pieces), "to cut down on how long the locks are held". As this assumes that the shared read locks are held till the complete select statement has finished, if that is wrong (if locks are released when the row, or the page is read) then that approach would have no effect whatsoever....

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• Apache2: Limit simultaneous requests & throttle bandwidth per IP/client?

  - by xentek

  I want to limit simultaneous requests & throttle bandwidth per IP/Client on a single apache vhost. In other words, I want to ensure that this site, which hosts large media files, doesn't get hammered by someone trying to download everything all at once (just happened the other night). I'd like to limit the outgoing transfer speed overall for this site, as well as limit the number of connections a single IP can make to the server to a sane default (i.e. within normal browser limits for multiple requests so page loads aren't effected too much). Bonus points if I can actually scope it to file types (i.e. leave web files alone, but apply these rules to just the media files). We're running Ubuntu 9.04 on all the servers, and have two apache/php servers being load balanced via Round Robin by a squid proxy server. MySQL is running on its own box as well. We've got plenty of bandwidth to give them, so I don't really want overall caps, but just want to throttle the amount of memory/CPU it takes to serve this site. There other sites on these servers that we don't want to apply these rules too, just want to keep this one from hogging all the resources. Let me know if you need more info! Thanks in advance for your suggestions!

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• Active Directory problems while trying to perfom compare operation

  - by Alex

  I have CentOs 5.5 with Apache 2.2 and SVN installed. Also I have Windows 2003 R2 with Active Directory. I'm trying to authorize users via AD so each user have access to repo if he is a member of corespondent group in AD. Here is my apache config: LoadModule dav_svn_module modules/mod_dav_svn.so LoadModule authz_svn_module modules/mod_authz_svn.so LDAPVerifyServerCert off ServerName svn.mydomain.com DocumentRoot /var/www/svn.mydomain.com/htdocs RewriteEngine On [Location /] AuthType basic AuthBasicProvider ldap AuthzLDAPAuthoritative on AuthLDAPURL ldaps://comp1.mydomain.com:636/DC=mydomain,DC=com?sAMAccountName?sub?(objectClass=*) AuthLDAPBindDN [email protected] AuthLDAPBindPassword binduserpassword [/Location] [Location /repos/test] DAV svn SVNPath /var/svn/repos/test AuthName "SVN repository for test" Require ldap-group CN=test,CN=ProjectGroups,DC=mydomain,DC=com [/Location] When I'm using "Require valid-user" everything goes fine, "Require ldap-user" also works. But as soon as I use "Require ldap-group" authorization fails. Trere are no errors in apache logs, but Active Directory shows folowing error: Event Type: Information Event Source: NTDS LDAP Event Category: LDAP Interface Event ID: 1138 Date: 10/9/2010 Time: 1:28:52 PM User: MYDOMAIN\binduser Computer: COMP1 Description: Internal event: Function ldap_compare entered. Event Type: Error Event Source: NTDS General Event Category: Internal Processing Event ID: 1481 Date: 10/9/2010 Time: 1:28:52 PM User: MYDOMAIN\binduser Computer: COMP1 Description: Internal error: The operation on the object failed. Additional Data Error value: 2 0000208D: NameErr: DSID-031001CD, problem 2001 (NO_OBJECT), data 0, best match of: 'DC=mydomain,DC=com' I'm confused by this problem. What I'm doing wrong?

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• when to upgrade server to include more cores, versus more processors, versus additional server?

  - by gkdsp

  The server hosting market is separated into single, double, qual, etc., processors, where each processor has several cores, or CPUs. My company will offer a Linux-based web application that relies on an Apache web server and a middle tier for business logic. The middle tier is used to crunch math, and return result to a client. Many clients may access the application simultaneously. The company will start with one processor having 4 cores. I'm trying to understand how the app uses the cores and then how to scale the application as business grows, in terms of servers/processors/cores. For example, I'd assume initially one core would be used for Apache, and the other 3 used to process client's requests for math crunching... Question 1: does that mean, with the 3 cores available, I can handle 3 separate client requests simultaneously (e.g. 1 for each of 3 cores)? I mean, except for the shared RAM, is this effectively like having 3 individual machines (from pt of view or processing client requests simulaneously)? Or, only one client's request may be processed at any one time, but that client's request is divided up into up to 3 cores depending on the type of process running that does the math crunching and whether or not it can take advantage of multi threading (so the # of cores impacts how fast any one client request completes)? I'm confused about what the cores mean to the application here. Question 2: As the business grows and more client requests need to be processed, should the server be upgraded to (A) a new machine with more cores, (B) a new machine with two processors, 4 cores each, or (C) keep the original server and add another server with a single processor? Which route provides the most efficient way to scale the application, in terms of processing more client requests per time interval? Is the choice, for example, limited by RAM (when you need more RAM than box can handle it's time to add another server), or something else? Question 3: Is the total number of client requests processed simultaneously equal to the number of cores times the number of servers (minus the one core for Apache)?

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• Problem with ubuntu 10.10 running from USB drive

  - by Surjya Narayana Padhi

  I recently downloaded Ubuntu 10.10 and created an USB drive with that. I started to run the Ubuntu from that USB drive. But I am facing so much problem. I am thinking why its not so much easy like Windows to do all my job in ubuntu. Always I get some error message or to install something. This time I am getting the following errors. I am trying to download and install Aircrack-ng. So used the command sudo apt-get install aircrack-ng. But the installation stops with the following error : update-initramfs: deferring update (trigger activated) cp: cannot stat `/vmlinuz': No such file or directory dpkg: error processing bcmwl-kernel-source (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: initramfs-tools bcmwl-kernel-source E: Sub-process /usr/bin/dpkg returned an error code (1) I don't even have the aptitude command installed till now. Are all these errors because of I am running the ubuntu from USB drive? Is there any simple and easy way to go to Ubuntu Software Center and download all the required essentials at one shot and then Aircrack-ng? I could not find the Aircrack-ng in Ubuntu Software Center Can anybody give me detail steps to solve all my problems above. I am frustrated searching for updates and installations. When something works and something does not work. Can anybody suggest me how I should proceed after installing ubuntu to run on a USB drive. So that I can use the OS like Windows. Like software download,wireless driver, sound, video, documents, C:, D: all things should be there. Please somebody help.

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• IIS6 site using integrated authentication (NTLM) fails when accessed with Win7 / IE8

  - by Ciove

  Hi, I'm having pretty similar problems as described in case 139099, but the fix there doesn't seem to work for me. Here's the details: Server: Win2003Srv R2 SP2 (stadalone, not a member of a domain). IIS6, TCP/443 (https). Anonymous access disabled. Integrated Windows authentication enabled. Local useraccouts Each useraccount has own virtual folder with change access and read access to site root. The 'adsutil NTAuthenticationProviders "NTLM"' -thing set to site root and useraccount's virtual folder. Client: Win7 Enterprise Member of a AD-Domain IE8 Allows three login attepts then fails. Using [webservername][username] in the logon window (Windows security) Logon using other browsers (Chrome and Firefox) works OK. The Web services log shows one 401.2 and two 401.1 events. The Security Event log shows two events, first is Fauilure Audit (680), The second event is Fauilure Audit (529) with these details: Logon Failure: Reason: Unknown user name or bad password User Name: [username] Domain: [webservername] Logon Type: 3 Logon Process: NtLmSsp Authentication Package: NTLM Workstation Name: [MyWorkstation] Caller User Name: - Caller Domain: - Caller Logon ID: - Caller Process ID: - Transited Services: - Source Network Address: [999.999.999.999] Source Port: 20089 Any ideas appreciated.

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• Small maximum number of connections on a Linux router

  - by Eugene

  I have a Linux box acting as a router with no iptables or other firewall and no networking applications running on it, just pure router. I've put it in a test environment that generates many TCP connections, each having unique source and destination IP, and those connections go through this router. I'm observing that number of connections successfully created rise to approximately 500 and then no more connections can be created for several minutes, then another 100 connections can be created and there is another pause, and so on. If 10 connections for each source-destination pair are created, then maximum numbers go about 10 times up, so the problem is probably with many connections from different IPs. As traffic is simply routed, it doesn't have to do with number of file descriptors, iptables connection tracking and other things often proposed to check in similar cases. The box has plenty of free RAM and CPU, both NICs are gigabit. The kernel is 2.6.32. I've already tried increasing net.core.*mem_max, net.core.netdev_max_backlog and txqueuelen on both NICs, with completely no effect. What else should I check ? Is there some rate-limit in the kernel itself ?

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• How to start MSSQL Server with corrupt model db

  - by Jordan McGuigan

  After moving some databases around (restoring, deleting, etc) we experienced an issue creating new databases. Specifically, When trying to create a new database MSSQL Server it failed because the "The database 'model' is marked RESTORING and is in a state that does not allow recovery to be run". As some online solutions suggested, we tried to Start and Stop the MSSQL Service. Service would not restart because "Could not create tempdb. You may not have enough disk space available. Free additional disk space by deleting other files on the tempdb drive" (FYI: the drive has 100gb of free space). Tried restarting the machine the MSSQL Server is running on. When the server came back online, we received the same error. We have tried deleting tempdb.mdf and restoring the modeldb from the templates folder, but neither of these solved the issue. We are unable to connect to the database, even in single user mode. Many of the online solutions have us running SQL commands against the server, but we are unable to connect (even in single user mode) to the DB to run commands against the server. Specific error messages: Database 'model' cannot be opened. It is in the middle of a restore. (Microsoft SQL Server, Error: 927) The SQL Server (MSSQLSERVER) service is starting. The SQL Server (MSSQLSERVER) service could not be started. A service specific error occurred: 1814. We need the server up and running again ASAP.

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• iptables: How to combine DNAT and SNAT to use a secondary IP address?

  - by Que_273

  There are lots of questions on here about iptables DNAT/SNAT setups but I haven't found one that solves my current problem. I have services bound to the IP address of eth0 (e.g. 192.168.0.20) and I also have a IP address on eth0:0 (192.168.0.40) which is shared with another server. Only one server is active, so this alias interface comes and goes depending on which server is active. In order to get traffic accepted by the service a DNAT rule is used to change the destination IP. iptables -t nat -A PREROUTING -d 192.168.0.40 -p udp --dport 7100 -j DNAT --to-destination 192.168.0.20 I also wish all outbound traffic from this service to appear to come from the shared IP, so that return responses will work in the event of a active-standby failover. iptables -t nat -A POSTROUTING -p udp --sport 7100 -j SNAT --to-source 192.168.0.40 My problem is that the SNAT rule is not always run. Inbound traffic causes a connection tracking entry like this. [root]# conntrack -L -p udp udp 17 170 src=192.168.0.185 dst=192.168.0.40 sport=7100 dport=7100 src=192.168.0.20 dst=192.168.0.185 sport=7100 dport=7100 [ASSURED] mark=0 secmark=0 use=2 which means the POSTROUTING chain is not run and outbound traffic leaves with the real IP address as the source. I am thinking I can set up a NOTRACK rule in the raw table to prevent conntracking for this port number, but is there a better or more efficient way to make this work? Edit - Alternative question: Is there a way (in CentOS/Linux) to have an interface that can be bound to but not used, such that it can be attached to the network or detached when a shared IP address is swapped between servers?

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