/ - rtt - IT Resource

  • grep regular expression match number range between specific numbers


    grep -E servers1[2-6] somefile.txt The 1 before the [ bracket means that the number must start with one and can be between 1 and [2-6] or in plain English between 12-16.  ........
  • HP DL385 G7 Linux BIOS Update Flash


    wget https://downloads.linux.hpe.com/repo/spp/rhel/6/x86_64/current/CP017004.scexe --2018-08-16 05:11:16--  https://downloads.linux.hpe.com/repo/spp/rhel/6/x86_64/current/CP017004.scexe Resolving downloads.linux.hpe.com (downloads.linux.hpe.com)... 15.249.152.85 Connecting to downloads.linux.hpe.com (downloads.linux.hpe.com)|15.249.152.85|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 1525561 (1.5........
  • vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down)


    [root@localhost:~] vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down) vsphere distributed switch vmotion not working [root@localhost:~]  esxcfg-route -l VMkernel Routes: Network          Netmask          Gateway          Interface &........
  • VMWare Vsphere VCSA Graphical Install Creates json


    yes it does create its own json ============================================ cat /tmp/vcsaUiInstaller/ovftool-20180809-175238948-20180809-175603497.log |grep -i json 2018-08-09T17:56:04.238-07:00 verbose OVFTool[30966] [Originator@6876 sub=Default] Manifest file entry: SHA1(VMware-vCenter-Server-Appliance-6.7.0.12000-8832884_OVF10-file1.json) = 1deb658c724767697587d5909c4051c01813e6a1 -->     <ovf:File ovf:href="VMware-vCenter-Server-........
  • [warn] VirtualHost 10.2.5.101:443 overlaps with VirtualHost 10.2.5.101:443, the first has precedence, perhaps you need a NameVirtualHost directive


    [root@thetor2017 conf]# service httpd restart Stopping httpd:                                            [  OK  ] Starting httpd: WARNING: MaxClients of 3000 exceeds ServerLimit value of 300 servers,  lowering MaxClients to 300.  To increase........
  • Postfix How To Change Sending IP Address To Specific IP Binding or Interface


    I thought I'd post this becuase there is some bad information out there.  Some guides tell you to edit /etc/postfix/master.cf (-o smtp_bind_address=) but this doesn't work.  The same guide also says if you don't change it there you end up changing the listening IP/bind interface which is also not true. Here is a simple and effective way to change Postfix's sending/binding/outgoing IP address (very important for reverse DNS and so mail servers don't block you)........
  • VMWare 6.7 VCSA VSphere ESXi Management SSO Install Guide on Linux using the CLI


    #mount the VCSA DVD mount /dev/sr0 /mnt/cd #alternatively you could mount the iso directly mount -o loop vcsa.iso /your/mount/path #for this purpose we are using the CLI installer on Linux cd /mnt/cd/vcsa-cli-installer/lin64 #no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file ./vcsa-deploy Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........
  • OpenVPN cannot ping remote IP routing loop issue after connecting


    Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop.  This is because you need to use your normal ISP/LAN gateway to hit the OpenVPN server if it is remote/offsite as is usually the case.  So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........
  • How To Install Windows Server 7 8 10 12 2008 2012 2014 2016 Servers Desktops using Linux tftp, dhcpd and samba


    It has been a big pain for a long-time to install Windows from a Linux environment.  I used to run a windows install server and it never worked right for some reason (the install would fail on most servers). Before getting start be sure to setup your samba share so once you boot into WinPE you can mount the install for whatever Windows you want /etc/samba/smb.conf [smbwinstall] path = /tftpboot/images/winstall guest ok = yes........
  • dhcpd.conf how to secure so only known and allowed clients will be given dhcpd IP address leases


    It's really simple and just a matter of the following line within the subnet declaration.   deny unknown-clients; See example below: subnet 10.25.20.0 netmask 255.255.255.0 {   range 10.25.20.11 10.25.20.254;   deny unknown-clients;   option routers 10.25.20.10;   option domain-name-servers 208.67.222.222;   ........
  • check if Apache uses worker MPM or prefork MPM


    apachectl -l Compiled in modules:   core.c   prefork.c   http_core.c   mod_so.c It is "prefork.c" so in httpd.conf these settings are what you would use (if you use worker.c it won't have any impact): <IfModule prefork.c> StartServers      2 MinSpareServers   5 MaxSpareServers&nb........
  • How to verify SSL SHA-1 Certificate Fingerprnit Signature of your mail/web server to avoid hijacking/man-in-the-middle attacks


    This is especially helpful if you run your own servers.  If you are presented with an error message or warning that the signature has changed or does not match the IP/domain you are connecting to you always want to verify manually. So your e-mail/web client will show you an SHA-1 fingerprint like this: "Could not verify this certificate because the issuer is unkown" or other reasons such as a mismatch in IP/domain. It will also show you........
  • root/home directory has ownership changed to the wrong user/owner mysteriously


    I figured out what caused this but don't have the solution just yet.  I would deploy a certain script from a .tar.gz to some servers and found that /root was always owned by user and group "1000.1000".  This corresonded to the user who made the .tar.gz. For some reason when extract normally with "tar -zxvf file.tar.gz" it impacts the parent directories ownership.  There must be some recursion going on or possibly the .tar.gz but I haven't f........
  • PYCURL ERROR 22 - The requested URL returned error: 404 Not Found Solution


    # yum -y install qemu-kvm Loaded plugins: fastestmirror Setting up Install Process Loading mirror speeds from cached hostfile  * base: mirror.lzu.edu.cn  * elrepo: ftp.utexas.edu  * epel: ftp.jaist.ac.jp  * extras: mirrors.aliyun.com  * openvz-kernel-rhel6: mirror.fdcservers.net  * openvz-utils: mirror.fdcservers.net  * updates: mirrors.nwsuaf.edu.cn Resolving Dependencies........
  • possible SYN flooding on port 80. Sending cookies.


    Errors like this are shown on high usage servers and ports so it is common to see it on http and even imap ports: possible SYN flooding on port 80. Sending cookies. The Linux kernel will even detect flooding on OpenVZ containers: possible SYN flooding on ctid 6000, port 993. Sending cookies. In many cases this is not an issue and is more so simply a result of regular, but high usage traffic.........
  • Cannot load /etc/httpd/modules/mod_file_cache.so into server: /etc/httpd/modules/mod_file_cache.so:


    Stopping httpd:                                            [FAILED] Starting httpd: httpd: Syntax error on line 73 of /etc/httpd/conf/httpd.conf: Cannot load /etc/httpd/modules/mod_file_cache.so into server: /etc/httpd/modules/mod_file_cache.so: cannot open shared obje........
  • openvz yum problem Centos 6.5 cannot find file on mirror:


    #solution Edit /etc/yum.repos.d/openvz.repo For the first two entries comment out #mirrorlist and uncomment #baseurl and then it worked openvz yum problem Centos 6.5 cannot find file on mirror: yum update Loaded plugins: fastestmirror Determining fastest mirrors  * openvz-kernel-rhel6: mirrors.ustc.edu.cn  * openvz-utils: mirrors.ustc.edu.cn base      ........
  • HP Procurve Switch 2824 CLI Telnet Experience , Guide and Tutorial


    telnet 192.168.1.54 ------------------------------------- ProCurve J4903A Switch 2824 Software revision I.10.77 Copyright (C) 1991-2009 Hewlett-Packard Co.  All Rights Reserved.                            RESTRICTED RIGHTS LEGEND  Use, duplication, or disclosure by the Government is subject........
  • HP XW9400 Motherboard In Desktop Issues


    Fortunately the format is EATX so an EATX case will work and the screw layout is standard. You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case). XW9400 Motherboard Issues Size: 12" x 13" Proprietary Power Connector Proprietary CPU Power Connector Proprietary Memory Power Connector Fan connectors are 4 pin so you will need some kind of adapter.........
  • ResourceManager[31705]: CRIT: Resource STOP failure. Reboot required!


    ResourceManager[31705]: CRIT: Resource STOP failure. Reboot required! This happened on a cluster I am running with heartbeat for no particular reason that I can figure out. The box ended up rebooting itself for some reason.  It was not a big deal in the sense that the other servers in the cluster kept running but it would be nice to find the cause of this.........
  • Windows 2012 Server R2 Install Error "windows cannot find the microsoft license terms windows 2012 server install"


    windows cannot find the microsoft license terms windows 2012 server install This is actually because you are using less than 576MB of RAM.  In my case I was installing on a KVM VPS with 512MB of RAM.  This issue would apply to any physical or virtual server with less than 576MB of RAM.  This includes Virtualized VPS Servers with XEN HVM, KVM, VBOX, VMWare etc.. or Dedicated Servers with such little RAM. It's very misleading of course since it has not........
  • Windows 2008 Server Trial How To Activate & Extend the Trial


    To activate your Windows 2008 server trial which gives you 180 days: Start -> Right Click (My Computer). Click "Activate Windows now" To renew your license for 6 days (can be done 3 times): Start -> Type this command: slmgr.vbs -rearm Wait a few minutes until it says it is successful (unless you get that message it has not worked or been done)........
  • How to Enable RDP Remote Desktop in Windows 2008 Server


    Start -> Administrative Tools -> Server Manager Under "Computer Information" click "Configure Remote Desktop". Under "System Properties" choose the type of "Allow connections" you want. That's all there is to enabling RDP Access in 2008 server.........
  • cPanel Find/Set Main DNS Servers for Template Howto


    Go to: "Server Configuration" -> Basic cPanel & WHM Setup Scroll to: "Nameservers" (at the bottom) From there you can set the names of the nameserver and their IPs. It's very weird and confusing that nothing under IP Functions/DNS has or links to this.........
  • CPanel suhosin install failed


    /scripts/phpextensionmgr install PHPSuHosin Updating md5sum list Fetching http://httpupdate.cpanel.net/cpanelsync/easy/targz.yaml (connected:0).......(request attempt 1/12)...Resolving httpupdate.cpanel.net...(resolve attempt 1/65)...     Fetching http://httpupdate.cpanel.net/mirror_addr_list (connected:0).......(request attempt 1/3)......connecting to 74.50.120.123...@74.50.120.123......connected......receiving...100%......request success......Done........
  • Dell FS12-NV7 2U Server Information and Guide


    I've got one of these for testing projects from work at home and got more than I bargained for with the time I've spent on it due to the storage handing/Perc 6/i cards. My particular model came with the following: 2U Rack Mount Server with Rails 2xOpteron 2373 EE (Quad Core, there is a 6-core version that can be found at times) 16GB RAM 2 x 250GB Seagate SATA 2 x Dell Perc 6/i (horrible and a nightmare to work........
  • CPanel How To Create/Edit Default Nameservers


    CPanel -> Basic cPanel & WHM Setup At the bottom you'll see them, set the nameservers you want to use and the corresponding A record if needed. Then all new domains will use those settings/nameservers. It's strange that there's no section for this specifically.........
  • GoDaddy How To Register and Create/Use Your Own DNS Name Servers


    http://support.godaddy.com/help/article/668/registering-your-own-nameservershosts?pc_split_value=1 Log in to your GoDaddy Account. Click on "My Account" at the top left. Click on "Domains". Click on the "Launch" button for the domain you want to create the nameservers for. Find........
  • open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted - Solution


    open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted [   96.084502] kvm: disabled by bios Any of the above means that "Virtualization" is not enabled in your BIOS.  Most servers and Desktops (non-mainstream) can do this no problem but leave it off by default.  Note that some systems even though the CPU supports it, don't allow enabling of Virtualization for some reason (especially some lap........
  • stat=Deferred: 451-Non-existent domain mailserver.com


    Jul 11 15:20:58 tor sendmail[9617]: r6AKjOD07: to= mailserver.com was the hostname of the server, sendmail sends this by default and many mailservers will reject mail to a hostname that does not resolve or exist. The easiest way is just to change the hostname and make sure it does resolve to something. I read there is a way in sendmail.mc to manually set a hostname but I never got it working: vi /etc/mail/sendmail.mc define(`confDOMAIN........
  • iptables redirect ports to a different host and port + NAT Masquerade howto/solution


    This is important if you need public access to internal IPs such as at your office and don't want to use a VPN just to SSH into different servers: Below forwards the port "10001" to the IP 192.200.5.53 on port 22 (of course adjust it to your needs). iptables -t nat -A PREROUTING -p tcp --dport 10001 -j DNAT --to-destination 192.200.5.53:22 Remember to enable MASQUERADE on your NAT IPs or they won't be able to talk to the outside world (........
  • Solution ERROR 1146 (42S02): Table ‘mysql.servers’ doesn’t exist - when running flush privileges


    flush privileges; ERROR 1146 (42S02): Table ‘mysql.servers’ doesn’t exist This happened to me on a system running Centos with the REMI repo and a new version of Mysql 5 (which the official Centos/RHEL does not support on version 5). The solution is just to run this program "mysql_upgrade", after that flush privileges will work. mysql_upgrade........
  • eth0 changed to eth1 or eth2 and the solution to fix it


    If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs.  The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a different MAC, it assigns it one higher (eg. eth1). See the example below, I have eth2 now so how do I fix it?........
  • Directadmin Log File Locations


    This is a handy link and list of all the relevant Directadmin log files and related servers.   http://help.directadmin.com/item.php?id=11   DirectAdmin: /var/log/directadmin/error.log /var/log/directadmin/errortaskq.log /var/log/directadmin/system.log /var/log/directadmin/security.log Apache:........
  • Samsung 4GB 1Rx4 DDR2 PC5300F FBDIMM Running Hot


    sensors|head i5k_amb-isa-0000 Adapter: ISA adapter Ch. 0 DIMM 0:+115.0°C  (low  = +127.5°C, high = +127.5°C)  Ch. 0 DIMM 1: +63.5°C  (low  = +127.5°C, high = +127.5°C)  Ch. 0 DIMM 2: +61.0°C  (low  = +127.5°C, high = +127.5°C)  Ch. 1 DIMM 0: +65.0°C  (low  = +127.5°C, high = +127.5°C)  Ch. 1 DIMM 1: +75.0°C&........
  • Lantronix KVM/IP Keyboard/Mouse not working in BIOS before booting the OS


    I've run into two issues with Lantronix based KVMs on various servers and here's how I solved them (with that said I like these units as they are Java based and OS independent and work very well, unike some other models like Startech). 1.) If you are connected by USB only and you're sure USB support from the BIOS is enabled, you just need to click the following in Lantronix Interfaces -> Keyboard/Mouse Check "Force USB Full Speed Mode", this fixed the issu........
  • Setup PXE Boot using Centos and dhcpd, tftp and syslinux


    This is something I often setup for clients because it's very helpful for people in datacenters, this allows custom OS installs on demand, you can customize it more by using kickstart etc.. but here's a base I use before customizing more: This little script below will install everything you need to get booting by PXE Linux. It also assumes you set a local IP (be sure not to overwrite your existing IP) on eth0:0 (note the :0) as 192.168.1.10 and it........
  • Disable SELinux How To Tutorial Solution


    Here is a quick script that works on most Centos versions to disable the virus/SELinux from blocking basic functionality. The first echo 0 statement disables SELinux instantly but it will still be enabled on reboot. The second line disables it permanently. #!/bin/bash #disable SELinux Immediately echo 0 > /selinux/enforce #disable SELinux Permanently sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config........
  • KVM/QEMU Base/Template Images and the power they provide


     qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2 Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB -b the source/base image -f format is qcow2 and the location of the destination image What is so special about this?  It's even quicker than creating a template with OpenVZ but this is an actual OS. It saves time a........
  • ip_conntrack: table full, dropping packet. solution for Linux RHEL/Centos/Debian


    ip_conntrack: table full, dropping packet. A lot of clients I've seen have this issue, it really seems the default level is way too small.  Once this connection tracking table becomes full then packets get dropped which is obviously a bad thing. One thing to be mindful of though is that 350 bytes of memory are used per entry so there is some justification for not keeping it too high.  However, if you have multiple servers running or high traffic daemons........
  • Centos how to upgrade from PHP 5.2 to 5.3 without downtime


    This may sound silly but there will be conflicts/issues with the default Centos repository so you have to use a third party like remi (I prefer not to do this but it's the only option unless you migrate your sites/data to another server or can stand some downtime-not an option IMHO on a production server). You may need to upgrade to PHP 5.3 to run Joomla or many other reasons. Your host needs to use PHP 5.2.4 or higher to run this version of Jo........
  • MySQL Authentication fails after Upgrade to Version 5.5


    ERROR 1045 (28000): Access denied for user 'contentmanager'@'localhost' (using password: YES) For fun I thought I'd reset the password: GRANT ALL ON thecontent.* TO contentmanager IDENTIFIED by 'dfdfsdfdsfsdfsd'; ERROR 1470 (HY000): String 'contentmanager' is too long for user name (should be no longer than 16) This is ridiculous that this new version has some bizarre 16 character username limit and not only that but i........
  • What's Needed To Fix Linux


    I really am a Linux fan but my comments here may not show it.  Although I'm quite familiar with Linux CLI to administer servers, I find Linux GUI OS's like Ubuntu at times very clunky. This is partially because there's no such thing as a "self-made" Linux from scratch where the UI was designed by a single team.  Linux is made up of several different projects that are generally completely separate and this lack of integratiion is a key issue that makes things f........
  • rpmforge: [#### ] 471/10722Segmentation fault yum[18934]: segfault at 0000000000000000 rip 00002ade62153a30 rsp 00007fff76f9fe58 error 4


    A few days ago this happened on multiple Centos 5 servers and apparently anyone using rpmforge was affected by this error and there was no solution other than disabling that repo to fix it. To some this highlighted a few points, that there is a reason RHEL exists with full paid support, and also that this could be a vulnerability and huge flaw with yum.  A yum search or install should not segfault just because the rpmforge repo goes down. Fortunately it came back up........
  • Openvz CPT ERR: cc4c0800,28000 :Unknown image version: 304. Can't restore.


    CPT ERR: cc4c0800,28000 :Unknown image version: 304. Can't restore. This happens when you live migrate between OpenVZ servers with different kernels running, at least significantly different by date. There is no solution except to make sure you're running the same kernels on all machines, or at least not kernels that are much older or different (this is just a guess though, you should ensure all kernels are the same).........
  • Openvz YUM Error Solution to "[Errno -1] Metadata file does not match checksum Trying other mirror."


    It's weird because I have a nearly identical box and setup and I can update the ovzkernel-PAE* just fine but on this box it doesn't work. I only get this error with the openvz.repo and not others such as Centos-Base.repo With my other server it works normally: ================ Setting up Update Process Resolving Dependencies --> Running transaction check ---> Package ovzkernel-PAE.i686 0:2.6.18-238.12.1.el5.0........
  • List of Free Public DNS Servers IP Addresses


    One thing to note about DNS servers and providers is that they aren't always trustworthy, not even if they're Google or your favorite ISP.  Any DNS server can compromise your privacy, and they are likely tracking your browsing habits and keeping logs of it.  Sometimes it's for Marketing/Research purposes such as Google's GMail service which they admit is scraped/datamined.  I would expect nothing less from their DNS service. The other danger with such widely used and pu........
  • mysql enable slow query logging/Query Cache Solution - find/track cause of slow mysqld/high IO/CPU usage


    If you have a webserver and find you have high IO/lagginess MySQL is one of the first things to check.  It turns out MySQL was my problem and it was creating a high load on my server, especially for IO. How to Enable MySQL Slow Query Logging To Find Slow Performance/Queries vi /etc/my.cnf Add this anywhere under [mysqld] #slow queries log-slow-queries = /var/log/mysql/mysqlslowqueries.log long_query_time = 1........
  • Yahoo Mail (email) DNS Server Out Of Date Problems


    I don't expect this to be solved soon but some of Yahoo's DNS servers are out of whack.  I changed the IPs of some nameservers of some domains and now most Yahoo users can't e-mail to those domains! As you can see below by the "No MX or A records for mychangedomain.com", now Yahoo's DNS/mailserver DNS cache is wrong.  You would think they would at least have cached the old incorrect records, but instead for some reason their DNS cache has no entry and doesn't seem........
  • Apache MPM worker vs prefork


    find what MPM Apache is using, it will either be using "worker" or "prefork" apachectl -l Compiled in modules:   core.c   prefork.c   http_core.c   mod_so.c In my case it is "prefork" vi /etc/httpd/conf/httpd.conf Find the section that looks like this (by default one will normally exist for prefork and for worker, but in my case I only care a........
  • SPAMASSASSIN Enable Pyzor and DCC


    *Remember to restart spamassassin after all of this. DCC wget http://www.dcc-servers.net/dcc/source/dcc.tar.Z tar -zxvf dcc.tar.Z cd dcc-1.3.138/ ./configure;make;make install #enable DCC, uncomment the line that disables it near the top vi /etc/mail/spamassassin/v310.pre pyzor wget http://sourceforge.net/projects/pyzor/files/pyzor/0.5.0/pyzor-0.5.0.tar.gz/down........
  • SSH Tunnel Dynamic Proxy Stops Working Right Away even with Root and High Port


    I keep getting messages like this shortly after using the proxy (it works for a few seconds/page loads and then stops): channel 12: open failed: administratively prohibited: open failed I'm not sure what the issue is unless there's some kind of hardware firewall on the other end.  I've used this exact configuration on multiple servers with no issue and even disabled iptables etc..........
  • Postfix/Any Email Server check for Open Relay


    The first thing you need to remember is not to check from the same host/server itself.  This is a silly mistake I made, the reason is that many mailservers and especially postfix are configured to allow relaying from the localhost/same host.  If you do that you'll get a false positive. *Make sure you test from another host/system than the mail server itself! telnet yourmailserverhost.com 25 220 Courier (FreeBS........
  • email server messsages rejected without reverse DNS DNS check failure Client host rejected: cannot find your reverse hostname Cannot resolve PTR record


    Basically you should always be 100% sure that whatever IP your mail server sends out with has reverse DNS/PTR records.  Remember that unless you own your IPs then you won't be able to set your own reverse DNS.  Even if you were to create a reverse PTR record on your DNS servers it will be ignored. Reverse DNS is queried to pre-assigned DNS servers of your ISP, so therefore you'll need to contact your ISP/Colo/Hosting provider to do a reverse DNS entry. If you don't have........
  • MySQL Replication/Dual-Master vs Clustering


    Many people aren't aware but recently Dual-Master Replication setups have become increasingly popular.  That's because you get similar features and benefits of having a full-blown cluster (difficult to setup and maintain and requires I believe 3 servers just as controllers). With a dual-master you just have a different off-set for the keys and you should be good, but of course there is the chance that at some point replication will halt because of an unexpected or unforseen error........
  • named/bind cannot find zone file, load zone files without specifying full directory path/loading master file genuine.com.zone: file not found


    genuine.com/IN: loading master file genuine.com.zone: file not found _default/genuine.com/IN: file not found I always found it silly that no one really talks about this and apparently many like me and even control panels like Plesk were still using hard paths.  I always thought "why can't I just specify the name of the zone file and have bind find it".  Surely the default search path must be /var/named or somewhere else but there is no such thing.........
  • Webmin/Virtualmin when enabling bind: Failed to save enabled features : Virtualmin is configured to setup DNS zones, but this system is not setup to use itself as a DNS server. Either add 127.0.0.1 to the list of DNS servers, or turn off the BIND fe


    Webmin/Virtualmin when enabling bind: Failed to save enabled features : Virtualmin is configured to setup DNS zones, but this system is not setup to use itself as a DNS server. Either add 127.0.0.1 to the list of DNS servers, or turn off the BIND feature on the module config page. It means what it says, add "127.0.0.1" to /etc/resolv.conf........
  • Installing Webmin & Enabling SSL


    Webmin Setup Centos 5: wget http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html&ts=1294339690&use_mirror=surfnet [1] 24229 [2] 24230 [root@host ~]# --2011-01-06 21:48:20--  http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html Resolving downloads.sourceforge.net... 216.34.181.........
  • Virtualmin/Webmin Postfix Error: The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active ..


    Virtualmin Postfix Error: The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active ..       A problem was found with your Postfix virtual maps : No map sources were found in the Postfix configuration .. your system is not ready for use by Virtualmin. <- Solution  ........
  • ntpdate[30630]: no servers can be used, exiting


    You're not supposed to call ntpdate like that, it's part of the server and needs a bunch of different arguments. The chances are if your time is out of sync and you installed ntpd, you need to start the ntpd service.........
  • Ubuntu 10.04 Linux is still not ready for the Desktop world


    I am a huge fan of Linux and the idea of OpenSource but I've said it many times, there are still hurdles in today in 2010 for Linux as a Desktop.  Linux is still intended for servers at its very core.  This can be changed succesfully though, as Apple has shown us with Mac OS X based on FreeBSD. Half of the issue is lack of driver support and the other half is the Linux Kernel and Window Manages, KDE and GNome still both don't cut it (but they're getting closer). I'll........
  • Realtek r8169 1gbit/1000mbit NIC/Ethernet Goes Down/Halts on Large File Transfer/Heavy Network Usage


    This is obviously a bug in the r8169 kernel module and it seems to affect a lot of people.  I upgraded to the latest kernel and hope this won't happen anymore, as it is a very serious error.  This is especially serious for those who are running servers with this chipset, who can afford for the NIC to randomly go off-line for no apparent reason?   [655548.189113] type=1505 audit(1277067560.902:5): operation="profile_load" name="/usr/bin/freshclam&q........
  • FUSE/Curlftpfs mount ftp account as drive partition in Linux


    This is a great way to use your ftp server space, for example on your web hosting account (although I believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect.  Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc..   Name curlftpfs - mount a ftp host as a local directory Synopsis........
  • nginx - the ultimate load balancer


    You can find it for free at http://nginx.org/ I find nginx is simpler to setup than pound (it's not hard but I found it unintuitive and annoying), it seemed to make some basic setups overly complicated with the config file syntax. nginx on the other hand is perfectly suited in everyway, it is even simpler to setup and seems to be the most stable and most efficient any load balancer.  I would go as far as to say that a good nginx setup is more relia........
  • tar gzip: stdout: File too large - Error Size Limit on Large file > 17GB


    The folder I was trying to archive is about 72GB, but much like rsync at about 17GB it chokes because of the filesize.  What's with so many common and essential Linux tools having such limitations?  I guess it is likely that the authors never wrote their code with the idea that files would be so large but it's still very annoying.  It's important to stay on top of these limitations on production servers because I didn't realize what happened until I checked the file with "........
  • XMPP Chat Protocol using Jabber - Guide Tutorial Setup Linux Chat Server


    In Debian based distros: apt-get install jabber Reading package lists... Done Building dependency tree       Reading state information... Done The following packages were automatically installed and are no longer required:   fakeroot dkms Use 'apt-get autoremove' to remove them. The following extra packages will be installed:   jabber-common The following NEW packag........
  • Picking an FTPD (vsftpd) Server in Linux Centos/Debian


    I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * rpmforge: ftp-stud.fht-esslingen.de  * base: mirrors.netdna.com  * updates: updates.interworx.info  * addons: yum.singlehop.com  * extras: mirrors.netdna.com rpmforge   ........
  • Nice General Linux RAID 1 Guide


    Nice General Linux RAID 1 GuideFull examples/tutorials that should work for any Linux system using GRUB or LILO as the boot loader. This is the only tutorial I've seen that clearly shows how you can convert an existing non-RAID system to software RAID1 remotely, without ever having to be at the computer. This is important for people who co-locate or rent dedicated servers that they may not have physical access to in a timely manner. https://alioth.debia........
  • Intruder detection device uses behavioural analysis


    Intruder detection device uses behavioural analysisIntruder detection device uses behavioural analysis by Antony Savvas Monday 13 June 2005 Symantec is introducing a new intrusion detection product that uses behavioural analysis to block potential attacks on enterprise networks. The new Critical System Protection 4.5 system uses technology that Symantec acquired through last years purchase of Platform Logic. It is designed to protect deskt........
  • MySQL "Got error 28 from storage engine"


    I've gotten this error enough to bother posting about it, because I've come across so many servers where this happens, so what could "Error 28" possibly mean?  Is your database corrupt, or is this a sign of a RAID failure/corruption or even worse, bad blocks on a clients system who has no RAID and never took backups? No, check your free blocks, it simply means you have no space.  This was the result of a script that was overzealous and backed up the entire database........
  • Mysqld Solution - Can't init databases /usr/libexec/mysqld: Can't read dir of '/tmp/' (Errcode: 13) /usr/libexec/mysqld: Can't create/write to file '/tmp/ibyP1qUC' (Errcode: 13) 100215 7:02:24 InnoDB: Error: unable to create temporary file; errno


    100215 07:02:24  mysqld started /usr/libexec/mysqld: Can't read dir of '/tmp/' (Errcode: 13) /usr/libexec/mysqld: Can't create/write to file '/tmp/ibyP1qUC' (Errcode: 13) 100215  7:02:24  InnoDB: Error: unable to create temporary file; errno: 13 100215  7:02:24 [ERROR] Can't init databases 100215  7:02:24 [ERROR] Aborting 100215  7:02:24 [Note] /usr/libexec/mysqld: Shutdown complete 100215 07:02:........
  • Unixbench Score with Glusterfs/Openvz & Quad Core Xeon


    This is very disappointing since GlusterFS markets itself as a solution to deploy VPS servers on.  On the HN itself I get a Unixbench of about 360. I'm also using an SSH tunnel to secure the communications, but even before that, things seemed very slow.        #    #  #    #  #  #    #          #####&n........
  • Linux/Unix Open SSH Login Without Password Key Exchange including Debian, Redhat, Fedora, Ubuntu, BSD etc..


    In those 4 simple commands you can setup mutual key exchange between two sshservers by using a single login shell session and single window. *Just change the IP address examples of (10.10.0.2) to the target of your mutual key exchange.  It doesn't matter if the server is on a LAN or WAN (well unless the server is behind a firewall and you cannot SSH into it).........
  • [error] server reached MaxClients setting, consider raising the MaxClients setting - Apache


    Have you ever seen this dreaded message in your Apache/HTTPD /var/log/httpd/error_log? [error] server reached MaxClients setting, consider raising the MaxClients setting The error itself is slightly misleading.  I believe this happened to one of my servers, I found Apache was running still, and that you could telnet to port 80 but no respnose would be given. For some reason my error log initially did not have the above error, but after a restart I saw........
  • SSH Server Slow/Lagged/Delayed Login Response


    This is really something the SSH Server developers should consider.  The cause of this annoyance is because of failed DNS lookups on your IP address, which is especially common for many dedicated/col-located servers and also computers on internal NAT/private networks. The chances are this is the cause of your SSH Slow/Delayed Login problems. The easy solution to SSH Login Problems Edit /etc/ssh/sshd_config Add this line to disable r........
  • Samba SMB Error - Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD


    Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD That happens when trying to use smbclient to connect to a share.  The weird thing is that I can authnenticate just fine from Windows XP. It is partially my mistake, I forgot this share does have a password.  I've tried authenticating with the correct user and also with "Guest" because this works in Windows.  In Linux I ........
  • 1U Servers are Loud - We Have The Quiet Solution


    I've read a lot of people complaining that their 1U servers are too loud for the office, home or whatever strange places people might want to put them. Whenever I see the question asked, "what can be done about the noise", you'll see a myriad of silly answers like "you shouldn't have it at home or in your office at all", "1U servers are meant to be loud". These all might be valid points but they're not the solution.  A good example is a........
  • Rackable Systems and their Microslice Clustered 1U Servers


    I think there has been a lot of negative press towards Rackable Systems.  We will give their new solution credit that it is marketed very well, and comes prepackaged and ready to go. But let's cut through the hype of both sides, the people who love this concept and the people who hate it. What Rackable Systems have done is a first, to minimize space, power and costs into small servers.  This is great, and many companies have already built their own servers based........
  • ENOM Major Outage


    At this time we can't resolve Enom's website and all DNS requests to their 4 primary name servers are failing, although the hostnames themselves still resolve:    Name Server: DNS1.NAME-SERVICES.COM    Name Server: DNS2.NAME-SERVICES.COM    Name Server: DNS3.NAME-SERVICES.COM    Name Server: DNS4.NAME-SERVICES.COM    Name Server: DNS5.NAME-SERVICES.COM You would really think Enom, bein........
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