• VirtualBox How To Add iSCSI Storage using VBoxManage


    #to show all VBoxManage list vms #show ONLY running vms VBoxManage list runningvms VBoxManage storageattach test --storagectl "SATA" --port 0 --device 0 --type hdd --medium iscsi --server 192.168.1.91 --target "iqn.2018-12.local.abcrandom.target:sdb" --initiator "iqn.1982-01.ca.bla.tld:abc123" --t........
  • iSCSI on Centos 7 Configuration and Setup Guide for Initiator and Target


    initiator = client target = server These are the first concepts you should understand which is that in iscsi essentially the "initiator" is the client and the "target" is the server. iSCSI is derived from the old fashioned SCSI that us oldtimers grew to love. The "i" stands for Internet and the SCSI stands for "Small Computers Systems Interface" (SCSI). iSCSI Target (Server)Setup targetcli is the pac........
  • httpd AH00534: httpd: Configuration error: No MPM loaded. solution


    httpd AH00534: httpd: Configuration error: No MPM loaded. Simple Solution (assuming you don't have this line in httpd.conf aleady: echo "Include conf.modules.d/*.conf" >> /etc/httpd/conf/httpd.conf ........
  • bash script to remove modules from httpd.conf that are not actually installed


    confmodules=`cat /etc/httpd/conf/httpd.conf |grep -v ^#|grep "modules/"|awk '{print $3}'|cut -d "/" -f 2` for module in $confmodules; do echo "module=$module" if [ ! -f /etc/httpd/modules/$module ]; then linenum=`awk /"$module/{ print NR; exit}" /etc/httpd/conf/httpd.conf` sed -i "$linenum"s/.*// /etc/httpd/conf/httpd.conf &n........
  • bash scripting how to create a function


    function centos7 { release=`cat /etc/redhat-release|awk '{print $4}'|grep ^[7]` if [ "$release" != "" ]; then centos7='yes' fi } centos7 echo "$centos7" We create a function called "centos7" and then call it by just typing "centos7" We then access a variable that may be set........
  • How Does Cisco CUCM (Cisco Unified Communication Manager) Work?


    Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
  • systemd management using systemctl and journalctl to check systemd logs


    systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands: list-units [PATTERN...] List loaded units &nbs........
  • AMD Set Fan Speed and Other Powerplay Memory/CPU Timings with a Linux script


    You can do other things but this particular script is just to set all AMD cards to 80% fan speed (remember this script needs to applied everytime you reboot). You could set it is a cron or just throw it into /etc/rc.local basepath=/sys/class/drm for hwmon in `ls -1 /sys/class/drm|grep card[0-99]$`; do echo card=$hwmon; hwmonname=`ls $basepath/$hwmon/device/hwmon|grep hwmon[0-99]` hwmonpath=$basepath/$hwmon/device/hwmon/$hwmonname echo "ec........
  • How to download gajim 0.16.9 XMPP/Jabber client so you can use OMEMO encryption


    #Linux Mint 18.2 how to install gajim .16.9 so you can use OMEMO encryption: sudo apt-get install python-axolotl python-nbxmpp wget https://gajim.org/downloads/0.16/gajim-0.16.9.tar.gz tar -zxvf gajim-0.16.9.tar.gz cd gajim-0.16.9 ./autogen.sh ;make;sudo make install #if you get this error you need to get a newer python-nbxmpp from here: gajim Gajim needs python-nbxmpp >= 0.6.1 to run. Quiting...........
  • hwloc-nox set CPU affinity in Linux


    sudo apt-get install hwloc-nox Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: hwloc-nox 0 upgraded, 1 newly installed, 0 to remove and 530 not upgraded. Need to get 151 kB of archives. After this operation, 453 kB of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubunt........
  • MySQL change for Antelope format to Barracuda error solution


    Your database uses Antelope as the file format. Full UTF-8 support in MySQL and MariaDB requires the Barracuda file format. Please switch to the Barracuda file format. See the documentation MySQL full unicode support for details. In /etc/my.cnf under [mysqld] 180827 21:43:14 InnoDB: 5.5.59 started; log sequence number 1589339 180827 21:43:14 [ERROR] /usr/libexec/mysqld: unknown variable 'db_file_format=Ba........
  • How To Enable Nested KVM so guests can virtualize with hardware extensions


    #check if nested KVM is enabled by doing a cat on nested inside sys root@s14:~# cat /sys/module/kvm_intel/parameters/nested root@s14:~# echo "options kvm-intel nested=Y" > /etc/modprobe.d/kvm-intel.conf root@s14:~# echo "options kvm-amd nested=1" > /etc/modprobe.d/kvm-amd.conf root@s14:~# modprobe -r kvm_intel modprobe: FATAL: Module kvm_intel is in use. root@s14:~# modprob........
  • Linux bash shell doesn't show username, hostname or current path fix solution


    Usually this is because when you created your user you added a user but didn't create their home directory and/or for some reason your .bashrc and .bash_profile in ~ (home) is broken/missing. In your home just create the following files with the following content to solve it: .bashrc and .bash_profile. To apply it just relogin/start a new bash session # .bash_profile # Get the aliases and funct........
  • Debian/Ubuntu/Mint Linux How To Set VLAN in /etc/network/interfaces


    You can find many ways to specify the VLANin your network configuration but Ifind this is the simplest and quickest. In this case we are talking about a bridged adapter "vmbr0" but it works even if you just had a normal non-bridged interface. The key here is that in vmbr0 you'll notice there is no IP address. We just specify "manual". Below it is a similar stanza for "vmbr0.58" in this case 58 represents the VLAN (change........
  • PHP Displaying Blank Page on Apache


    Almost always the reason will be that the php.so file is missing but also that php.conf is misconfigured. In the problem machine it is actually PHP7 installed so if you reference PHP5 of course things wil be broken! Take for example here: cat /etc/httpd/conf.d/php.conf # # PHP is an HTML-embedded scripting language which attempts to make it # easy for developers to write dynamica........
  • PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/geoip.so' - /usr/lib64/php/modules/geoip.so: undefined symbol: GeoIP_country_code_by_name_v6 in Unknown on line 0


    PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/geoip.so' - /usr/lib64/php/modules/geoip.so: undefined symbol: GeoIP_country_code_by_name_v6 in Unknown on line 0 Solution: Edit geoip.ini vi /etc/php.d/geoip.ini Comment out the .so like so: ;extension=geoip.so service httpd restart........
  • Starting httpd: httpd: Syntax error on line 221 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/php.conf: Cannot load /etc/httpd/modules/libphp5.so into server: /etc/httpd/modules/libphp5.so: cannot open shared object file:


    Starting httpd: httpd: Syntax error on line 221 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/php.conf: Cannot load /etc/httpd/modules/libphp5.so into server: /etc/httpd/modules/libphp5.so: cannot open shared object file: No such file or directory This is basically caused by the PHPmodule specified in php.conf being non existent. The error tells us it couldn't fnd /etc/httpd/modules/libphp5.so........
  • ./xmr-stak: error while loading shared libraries: libmicrohttpd.so.10: cannot open shared object file: No such file or directory


    The solution is just to install libmicrohttpd-dev ./xmr-stak ./xmr-stak: error while loading shared libraries: libmicrohttpd.so.10: cannot open shared object file: No such file or directory libmicrohttpd libmicrohttpd10 - library embedding HTTP server functionality libmicrohttpd-dbg - library embedding HTTP server functionality (debug) libmicrohttpd-dev - library embedding HTTP server functionality (development) $ sudo apt-get i........
  • Debian Mint Ubuntu compiling xmr-stak


    sudo apt-get install libcurl4-openssl-dev git build-essential autotools-dev autoconf libcurl3 sudo apt-get install libcurl4-gnutls-dev git clone https://github.com/wolf9466/cpuminer-multi sudo apt-get install cmake libpthread-* libmicrohttpd-dev libssl-dev libhwloc-dev git clone https://github.com/fireice-uk/xmr-stak-cpu.git make install cd bin chmod +x xmr-stak-cpu ./xmr-stak -O xmr........
  • Linux Centos 7 HowTo Install Yarn


    https://yarnpkg.com/lang/en/docs/install/#centos-stable curl --silent --location https://dl.yarnpkg.com/rpm/yarn.repo | tee /etc/yum.repos.d/yarn.repo If you need node.js: curl --silent --location https://rpm.nodesource.com/setup_6.x | bash - yum install nodejs yarn........
  • Centos 7 - How To Install NFS and Mount Remotely


    Server Side Config 1.) First install nfs-utils yum -y install nfs-utils 2.) Configure nfs share Create a directory for your NFS share mkdir /datastore Create your NFS share in /etc/exports echo "/datastore 10.220.101.0/24(rw,sync,no_root_squash)" >> /etc/exports systemctl restart nfs........
  • linux mint image convert menu option missing solution


    Ialready have the caja-image-converter option installed but it shows nothing. Weirdly enough if you install nemo and nautilus converter it does show and work inside caja: The solution is to install *-image-converter sudo apt-get install *-image-converter Reading package lists... Done Building dependency tree Reading state information... Done Note, selecting 'n........
  • Postfix How To Change Sending IP Address To Specific IP Binding or Interface


    Ithought 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)........
  • How to qemu-kvm enable bridged networking in Debian Ubuntu Linux Mint on KVM containers


    I've read a few guides about this but they didn't work for me. sudo apt-get install bridge-utils #don't think the above is enough it won't work still even though you have by default an /etc/qemu-ifup that handles it if you have the right tools and setup sudo qemu-system-x86_64 -net tap -net nic -enable-kvm -cpu host,vmx=on ~/VirtualBox VMs/vsphere-vcenter/vsphere-vcenter.vdi W: /etc/qemu-ifup: no bridge for guest interface foun........
  • Install NFS (Network File System) On Debian Linux Ubuntu Mint Howto


    sudo apt-get install nfs-kernel-server #oops there are no exports so it won't startsudo /etc/init.d/nfs-kernel-server start* Not starting NFS kernel daemon: no exports. #we will use the /tmp/nfstestshare directory for our NFS share mkdir /tmp/nfstestshare #add it to /etc/exports (basically what NFS checks to determine what to make an NFS share) /tmp/nfstestshare 192.168.1.5(rw,sync,........
  • Relocating modules and starting up the kernel - VMWare ESXi 6.7 Error and Solution


    I had this error in an unsupported CPUon VMWare 6.7 and apparently this sometimes works especially on older VMWare versions like 6.5 5.5 etc (but in my case it did not). To make sure it proceed when you see "Loading VMWare" Hit "Shift+O" Then add "ignoreHeadless=TRUE" See an example below:........
  • 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........
  • Hard Drive Serial Number Examples


    The reason for this article is because a lot of us don't physically see our hard drives they are often remote in a datacenter etc and the actual serial number we see in SMART is not enough to check for some manufacturers. A good example is our first one the Toshiba === START OF INFORMATION SECTION === Device Model: TOSHIBA DT01ACA200 Serial Number: 33FMDW4AS........
  • Howto install ioncube loader to PHP by Zend


    First of all download the raw .so file from zend: Copy the one relevant to your PHPversion to /usr/lib64/php/modules/ eg.:cp ioncube_loader_lin_5.3.so /usr/lib64/php/modules/ Then in your /etc/php.d/ directory create the file: vi /etc/php.d/zend.ini zend_extension = /usr/lib64/php/modules/ioncube_loader_lin_5.3.so After that restart apache/httpd and you'll be good to go!........
  • not allowed to execute '/usr/bin/apt-get install eclipse' as root linux sudo user permisson issue and solution


    This is most likely to happen on a normal GUI system like Ubuntu or Linux Mint. If you or the user is meant to have sudo / root privileges it is as simple as editing the following files: Now assume your username is "iamtheuser" vi /etc/group adm:x:4:syslog,iamtheuser sudo:x:27:anotheruser,iamtheuser Find the above lines and add a comma and "ia........
  • postfix errors fatal: no SASL authentication mechanisms /usr/libexec/postfix/smtpd: bad command startup -- throttling solution


    Jul 3 22:12:17mailserver postfix/smtpd[6195]: fatal: no SASL authentication mechanisms Jul 3 22:12:18mailserver postfix/master[4881]: warning: process /usr/libexec/postfix/smtpd pid 6195 exit status 1 Jul 3 22:12:18mailserver postfix/master[4881]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling This only ever happens in my experience when the authentication method is actually Dovecot. Usually the problem........
  • mail command line examples of how to send an email using Linux / Unix and the Bash Shell or Scripting


    A simple way that may work for a lot of people who just need basic output for their scripts or daemons to announce an action is this: echo "body or message" | mail -s "realtechtalk.com" user@domain.com If you want to send a text file as the body just do this instead: mail -s "realtechtalk.com" user@domain.com < /tmp/sometxtfile.txt These are some ve........
  • 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/LANgateway 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........
  • Linux Mint Black Screen after boot no graphics solution


    This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help. Here is the short end of the stick that fixed it: sudo apt-get install mdm mate-desktop-environment Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
  • Intel NUC J3455 Linux Kernel freeze slowness 4.4.98 errors


    It looks like this has something to do with APIC but I am not sure. I have similar CPUs with a different MB and BIOS that work fine on the same type of kernel. A lot of time the issue is because of the C-step setting in the BIOS. The same thing happened on the 2.6 kernel with Centos 6 but this is a homebrew 4.4 kernel soI am not sure why it is happening when even Centos 7 (3.2) kernel works OK. Solution - It comes down to the BIOS set........
  • Linux Mint Ubuntu Debian How To Disable Webcam Automatically Onboot To Prevent Spying and Privacy Violations


    It is well known hackers, the NSA, CIA and other groups have created malware to secretly turn on your webcam and microphone on your phone, tv etc.. But fortunately on our computers and laptops we have some options. Most webcams use the "uvcvideo" kernel module / driver. You can disable this in two ways on boot. I recommend both just as a failsafe. Disable it on rc.local once your system boots automatically Add the followi........
  • Debian Linux Mint Ubuntu Disable Automatic apt-get update


    sudo chmod 000 /etc/cron.daily/apt-compat This is the easiest way to disable the cron without anything more invasive like deleting the file. After that you won't have anymore apt-get's starting. This can be critical for systems without much extra RAMthat is not in use. I've seen systems that have swapped and crashed over apt-get.........
  • Prevent SSH Bruteforce and Hacks By Disabling Password Authentication


    One simple way to keep your server public but almost impossible to hack via SSHis to disable password authentication over SSH. This means the only way in is via your own private key that only you should have. Edit your /etc/ssh/sshd.conf file Set this option PasswordAuthentication no Restart your SSH server. service sshd restart ........
  • Apache htaccess Custom ErrorDocument not working properly for root home page 403 Error Issue and Solution


    So I have a domain "testdomain.com". Inside test domain.com's root is the following .htaccess: Options +FollowSymLinks -Indexes ErrorDocument 403 /launch/index.html Order Deny,Allow Deny From All Allow From 192.168.1.2 When you visit anything other than root things work fine. Eg. if you visit http://testdomain.com/somedirfile.html It will show the right error in /launch/........
  • 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........
  • sudo: unable to resolve host


    sudo: unable to resolve host yourhostname No clue why sudo is doing that when running. Solution Check /etc/hosts You will probably find that it doesn't contain "yourhostname" for 127.0.0.1 Just update the hostname or add a field for your hostname like this: 127.0.0.1 yourhostname ........
  • Wordpress Instagram Post Modify Plugin To Add Tags


    I modified this code after quickly learning how Wordpress plugins actually work, how they're called etc.. was the first trick to modifying the code to add tags. Add this code after line 570 in wp-content/plugins/wp-instagram-post/classes/class-woo-igp.php &nb........
  • Unable to load dynamic library '/usr/lib64/php/modules/module.so' - /usr/lib64/php/modules/module.so: cannot open shared object file: No such file or directory in Unknown on line 0


    Getting this error on Centos 6 with PHP 5.3 when just running "php -v" PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/module.so' - /usr/lib64/php/modules/module.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: Cannot load module 'XCache' because conflicting module 'apc' is already loaded in Unknown on line 0 Solution:........
  • How to start screen in bash script or from /etc/rc.local on startup as a specific user


    It takes some tinkering the main thing is that the "-dmS" flag allows screen to start without a session which of course sudo won't have. solution: /usr/bin/sudo -u user /usr/bin/screen -dmS nameyouchoose /script/start.bash this doesn't work at all: /usr/bin/sudo -u user "/usr/bin/screen /script/s........
  • Linux How To Clone One System Harddrive to another remote system


    The easiest way is to use SSHand DD or a combination of netcat. SSHwill be a little slower due to encryption but is the most secure way (on two older systems the average clone speed is about 40-50MB/s). This is also OS independent as it doesn't matter what the source OS is because you are literallly cloning the drive so you retain the partition table and settings. Clone HDD using SSH and DD........
  • Centos How To Update to Glibc 2.14 Plus


    Centos 6 requires GLIBC 2.12 however a lot of new programs you would want to compile may need a newer glibc. You can't remove the old glibc since the whole OS is based on it but you can install the updated glibc alongside it and do an export pointing to your updated GLIBC. mkdir ~/glibc_install; cd ~/glibc_install wget http://ftp.gnu.org/gnu/glibc/glibc-2.14.tar.gz........
  • Syntax error on line 221 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/php.conf: Cannot load /etc/httpd/modules/libphp5.so into server: /etc/httpd/modules/libphp5.so: cannot open shared object file: No such file or direct


    Stopping httpd: [ OK ] Starting httpd: httpd: Syntax error on line 221 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/php.conf: Cannot load /etc/httpd/modules/libphp5.so into server: /etc/h........
  • possible SYN flooding on ctid 42131, port 80. Sending cookies. - Solution


    The Linux Kernel interpretated a very high volume of real traffic as a DDOS attack so it basically ends up blocking your web server. possible SYN flooding on ctid 42131, port 80. Sending cookies. Simple fix edit sysctl values for max_syn_backlog sysctl -w net.ipv4.tcp_max_syn_backlog=5000 To make them permanent edit /etc/sysctl.conf echo "net.ipv4.tcp_........
  • Install Windows From a Linux TFTP Server instead of using WDS Solution


    yum -y install samba vi /etc/samba/smb.conf https://www.kernel.org/pub/linux/utils/boot/syslinux/syslinux-6.03.zip mkdir syslinux;cd syslinux;unzip syslinux-6.03.zip mkdir -p /tftpboot/libs/ cp bios/com32/modules/linux.c32 /tftpboot/libs/ cp bios/com32/libutil/libutil.c32 /tftpboot/libs/ cp bios/com32/lib/libcom32.c32 /tftpboot/libs/ #add lib path echo "PATH libs" >> /tftpboot/pxeli........
  • Linux how to view video card make and exact model


    Normally lspci will show you just like this and would suggest they are exactly the same card: 1a:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/580] (rev e7) 1c:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/580] (rev e7) lspci -vnn is the answer As we can see one is a Gigabyte and the other is an MSI card. Wha........
  • yum how to install old obsolete packages


    This is important as unfortunately Centos may designate a package obsolete and the replacement breaks everything (eg. you have a config file and the new replacement is not at all compatible with it and it breaks your application). This is where disabling obsoletes comes into play, it can be done from yum but it doesn't work at the time I find. yum --setopt=obsoletes=0 install someapp However Ifind it still installs the new app and not the one you ask for........
  • ffmpeg vidstab to stabilize video


    I'm having trouble making it work on very shaky video the result seems kind of warped/blurry/fish eye like and not as good as some other examples I've seen: ffmpeg -i MVI_1285.MOV -vf vidstabdetect=shakiness=10:accuracy=15 -f null MVI_1285.trf ffmpeg -i MVI_1285.MOV -vf vidstabtransform=smoothing=30:input="transforms.trf" MVI_1285.MOV.mp4 I've played around with the shakiness, accuracy etc.. but not the smoothing part.........
  • userdel user userdel: cannot lock /etc/passwd; try again later.


    I am not sure why this happened I think it's because the file was in use by another duplicate process or script. userdel user userdel: cannot lock /etc/passwd; try again later. ........
  • linux cp and mv will not overwrite due to alias!


    This through me for a loop when I would do a cp -rf or mv -f nothing would get overwritten even if piping y or yes to the command. Type alias and you'll see why: alias cp='cp -i' alias l.='ls -d .* --color=auto' alias ll='ls -l --color=auto' alias ls='ls --color=auto' alias mv='mv -i' alias rm='rm -i' The -i is a safeguard against messing things up but however does mess things up worse when you know what........
  • ERROR 2006 (HY000) at line 567: MySQL server has gone away


    mysqldump or mysql query of a larger file/table ERROR 2006 (HY000) at line 567: MySQL server has gone away Add this to /etc/my.cnf max_allowed_packet=64M service mysqld restart........
  • vbulletin 4.2.5 after upgrading from 3.6 white screen fatal php errors


    The code may lead you to believe you have an incompatible template but if you are not trying to use an old template currently that is not the issue. I actually deleted all 3.x style templates to make sure. What the issue is, is old plugins that are not compatible but Vbulletin does not seem to account for this except that you'll see a fatal PHPerror. You should disable all plugins and then enable one by one until you find the one that is causing the issue. &........
  • Linux Unable to mount cifs/smb share in /etc/fstab


    sudo mount -a Unable to find suitable address. [35758.706993] CIFS VFS: Error connecting to socket. Aborting operation. [35758.707247] CIFS VFS: cifs_mount failed w/return code = -111 [35795.476160] CIFS VFS: Error connecting to socket. Aborting operation. [35795.476346] CIFS VFS: cifs_mount failed w/return code = -111 When the above happens "Unable eto find suitable address" it usually means the smb nam........
  • Centos 5.9 Working Vault Repo file


    Centos 5 is not supported running yum will produce an error like this: YumRepo Error: All mirror URLs are not using ftp, http[s] or file. Eg. Invalid release/ removing mirrorlist with no valid mirrors: /var/cache/yum/base/mirrorlist.txt Error: Cannot find a valid baseurl for repo: base Solution - Update this file CentOS-Base.repo # CentOS-Base.repo........
  • Disable SSH Password Authentication to Increase Security and Harden SSH Linux Unix Server Ubuntu Mint Centos Debian


    Just a note before you do this you should have a sure, guaranteed way into the system such as local, KVMor preferably publickey making bruteforce SSH absolutely impossible since there is no password to bruteforce and even if someone knew the password they wouldn't be able to login except from the local console (presumably you should make sure no one unauthorized has physical access). 1. Edit /etc/ssh/sshd_config Find the section like this:........
  • Linux bash script to see what connected computers respond to ping


    A great way when moving your equipment to a new location, new router/switch etc to help confirm what MAC has what IP: for ip in `arp -na|awk '{print $2}'|sed s/(//g|sed s/)//g`; do echo ping $ip ping -c 1 -w 1 $ip > /dev/null if [ "$?" == 0 ]; then echo "$ip UP" fi done........
  • OpenVZ error : Container start failed (try to check kernel messages, e.g. "dmesg | tail") Locked by: pid 166638, cmdline vzctl start 888171


    This container won't start after exhausting its memory. There are no relevant or helpful messages in dmesg or vzctl.log as well. Standard troubleshooting such as disabling PPP etc has not helped. 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Locked by: pid 166029, cmdline vzctl start 888171 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container already locked 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container was stopped 2017-07........
  • Centos 7 How To Change Hostname


    Some guides still use the old Centos 6 style (do not use /etc/sysconfig/network). In Centos 7 the file is /etc/hostname echo "HOSTNAME=yourhostname.com" > /etc/hostname........
  • Migrate Centos 7 from Single HDD to mdadm RAID 10 array:


    Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install! One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting The normal way will not work here if your Centos was using UEFI. Newer systems use it by default. The easiest way to check is to do an fdisk -l if your sy........
  • USB 3.0 External HDD Enclosure Seagate UAS problems - [sdd] tag#1 CDB: Write(16) 8a 00 00 00 00 01 70 04 08 68 00 00 00 08 00 00


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    mount -o bind /proc /sda2/proc mount -o bind /dev/ /sda2/dev mount -o bind /sys /sda2/sys chroot /sda2 mint / # mount -o bind /proc /sda2/proc mint / # mount -o bind /dev/ /sda2/dev mint / # mount -o bind /sys /sda2/sys mint / # chroot /sda2 mint / # cd ~ mint ~ # ls Desktop mint ~ # cd / mint / # ls bin Desktop dev-temp home&nb........
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    Kernel panic - not syncing: Attempted to kill init! Pid: 1,comm: init Tained: G I------------- 2.6.32-358.el6.x86_64 #1 Call Trace: [] ? panic+0xa0/0x16f [] ? do_exit+0x862/0x870 [] ? fput+0x25/0x30 [] ? do_group_exit+0x58/0xd0 [] ? sys_exit_........
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    Here's a proven example of what a bad hard drive can do, it was technically functioning OKin a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application. The truth is that this failing 1TBHitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..). After swapping it out, tabs change instantly, emails are not lagged, and........
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    Step #1 - Create Wrapper Script vi /usr/local/bin/phpsendmail #!/usr/bin/php ........
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    There are 3 pieces that are required to restore and make it work (of course consider if any kernel modules need to re-enabled and if you need to change the IPs): Copy the vz/private/VEID directory to /vz/private Copy the /etc/vz/conf/VEID.conf to /etc/vz/conf/ mkdir /vz/root/VEID After that you should be able to see the VE in vzlist -a You should then be able to start it normally.........
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    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........
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    The best way is to use rsync, I've set it up so it doesn't copy unnecessary files, or at least ones I'm sure aren't needed. Here is the rsync command Iused (adapt to your specific Thunderbird profile location): rsync -hazv user@remotehost.com:/home/user/.thunderbird/sbrer.default/* /home/user/.thunderbird/4nyb0.default/ --exclude=global* --exclude=Cache --exclude=ImapMail --exclude=Mail This is a great way to get your e-mail accounts going on a new c........
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    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........
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    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........
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    For whatever reason the current OpenVZ yum repo file enables the RHEL6 version of OpenVZ, why is this bad? Because if you're running Centos 5 it still defaults to using the kernel from RHEL6 which won't work on RHEL5/Centos 5. Ionly realized this after wondering why I couldn't boot into OpenVZ that it was using one meant for RHEL6. To fix the problem you have to edit /etc/yum.repos.d/openvz.repo and disable the "[openvz-kernel-rhel6]" section by changing........
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    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. Ibelieve 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........
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    This way should work on all Linux machines, at least RHEL/Debian (Ubuntu) based distros but most likely all and also should work on many Unix style machines I believe. Many OS's have tools to update the timezone, but most of them (even if command line) require several bloated packages and even Xorg/KDE based packages etc.. Your time zone info file is actually in /etc/localtime if you open this file in vi/vim/pico you'll see it's gibberish (binary code or another encodin........
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    A VPS Server I had just wasn't working right, code that I migrated there just wasn't working. For example, it kept telling me the connection to the database was unsuccessful, halfway through iterating through results it already had. Then I realized it wasn't my code. Ichecked my /proc/user_beancounters and found this: cat /proc/user_beancounters Version: 2.5 uid resource held maxheld barrier limit failcnt........
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    I was getting very frustrated one day wondering why it appeared my .htaccess file was being ignored and not processed by Apache. No matter what I did it was obvious that Apache didn't care about my .htaccess file. Then I realized that the default settings must be in effect, which is that my vhost didn't explicitly allow me to override the default settings. This usually comes down to your vhost settings. Make sure you have an entry like this in your Apache vhost settings in........
  • How To Save iptables firewall rules Centos/Redhat/Fedora Linux


    This is something that annoys a lot of people, fortunately the Redhat style OS's are the most simple in this respect. I disagree that Debian's way makes sense, it is more of a hackish approach in how they implement iptables. Anyway, for those who are using Redhat/Centos style OS's it is very simple. Set your rules from the shell/command prompt and to save the iptables firewall rules so they are remember/loaded on boot just run this command: service iptables........
  • Bash Script/Linux/Unix HTML/XML Parser


    There is a tool called "xml2" which will parse both HTML and XML scripts, this is very useful to do a mass extraction or conversion of data based on say an HTML table etc.. It becomes even more powerful using bash if certain tags are identified with a certain class="" attribute or something else unique to only the tags you want. Happy parsing.........
  • iPhone Backgrounder Adds True and Real iPhone multitasking on jailbroken phones


    Apple crippled the iPhone by not allowing multi-tasking of the non-primary apps. I use SSH a lot and I don't want to close my session just to check my e-mail, etc, now an app found in Cydia called "Backgrounder" allows just that. Although it's not perfect, we installed the correct one for "3.x" iPhones and hit "Reload SpringBoard" and the hour/circle glass has just been going for minutes. It seems like it installed fine even with the crash t........
  • iPhone 3GS 32GB "Harsh Review"


    Yes, Iadmit I finally got bitten by the hype as much as I can usually see through it all. Keep in mind this review is of the "stock" phone, no jailbreaking yet which is what really unleashes the customizability and whyI bought iPhone. I had better things to say about this phone before buying it, and it is a great phone, perhaps the best on the market by far, if not because of the Mac OS port onto the iPhone and all the apps, etc, etc. With that said........
  • iPhone Safari Browser and TinyMCE Support


    This is unfortunate and frustrating as many sites use it, a lot of people are frustrated that TinyMCE does not work on the iPhone Safari browser. Apparently the developer of TinyMCE's answer is "talk to Apple about it" It's really frustrating although, I wonder if any other mobile phones are able to use TinyMCE or not, whatever the case is it would be nice to find a solution to use TinyMCE on the........
  • Apple iPhone 3GS and predecessors are leading a revolution


    As much of a computer nerd as Iam, I'm usually a late adopter to technology for a few reasons. Ifeel most new hyped technologies and electronics are mainly fads, and I'm also cheap. Adopting later means you avoid the bugs, kinks and most importantly pay the lowest price, that's me being cheap again :) I never read much about the iPhone but Isaw all the hype around it and until recently I wasn't a big fan of anything Apple until a few years ago I realize........
  • SSH Slow Login even with SSHD UseDNS no parameter


    Icouldn't understand why on one system it took a few minutes to get the SSHlogin prompt when connecting to other systems. The other systems all had the UseDNS parameter set to no, which almost always resolves the login prompt delay. The reason is Ubuntu and perhaps Debian and other distributions /etc/nsswitch.conf file Edit yours to have the "hosts" line like so (notice that files and dns are the primary resolution choice........
  • resume: could not stat the resume device file


    resume: could not stat the resume device file I got that after migrating to a different physical hard drive, it wanted to resume from a swap partition that no longer exists. This is actually controlled by "uswsusp.conf" in /etc Just edit it and remove the device or change it to the correct new swap file.........
  • SSH Server Slow/Lagged/Delayed Login Response


    This is really something the SSHServer developers should consider. The cause of this annoyance is because of failed DNS lookups on your IPaddress, 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 SSHSlow/Delayed Login problems. The easy solution to SSH Login Problems Edit /etc/ssh/sshd_config Add this line to disable r........
  • SIOCSIFADDR No such device eth0 error while getting interface flags - eth0 Ethernet Device can


    Igot this after copying a VMWare image onto another machine in Debian. SIOCSIFADDR No such device eth0 error while getting interface flags The solution 1.) Find and edit the device line in persisent-net.rules note it will be prefixed with something like z25 or something else. vi /etc/udev/rules.d/z25_persistent-net.rules The easiest way is to comment anything out. If you are feeling........
  • 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 ........
  • Configuring OCFS2 Clustered File System on Debian Based Linux including Ubuntu and Kubuntu


    There's a lot of information and guides on OCFS2 for RHELand Centos Linux but the package setup and configuration is slightly different and this has thrown some people off. Installing OC2FS You should install the following packages to get started: apt-get install ocfs2-tools ocfs2console Configure OC2FS In RHEL/Centos the main configuration file is located in /etc/sysconfig/o2cb However in Debian based Linux it is located........
  • Viewing and Connecting to an SMB Samba Share on Windows/Linux/Unix


    This will give you the basic info needed to browse and connect to Samba shares from the command line. From the GUI of Gnome or KDE etc, it is pretty standard and straight forward. However, I've found very little guides on how to do it from the command line and if you're like me, a nerd who prefers command line for its simplicity and for remote use, this is the way to go. First get a list of all the Samba/SMB shares on the target. smbclient -L hostname........
  • SSH Problem User username from 127.0.0.1 not allowed because not listed in AllowUsers


    User username from 127.0.0.1 not allowed because not listed in AllowUsers What's going on? The user was created properly, it has been defined as having a shell entry and the entry for /etc/passwd and /etc/shadow is set just fine. This is a new and very smart/secure feature of SSHD. It is simple and yet effective, but also very annoying if you didn't know about it being implemented and that hand editing of /etc/ssh/sshd_config is required to allow a newly add........
  • BIND/NAMED woes


    Feb 5 01:39:33 server named[19768]: zone myzone.com/IN: serial number (12331465) received from master 127.0.0.2#53 < ours (200901281) The above is taken from /var/log/messages This can be annoying, it can happen for a variety of reasons. What seems to be happening here is that the slave realizes the time on the slave is ahead of the master, so it therefore assumes it has the most up to date copy and won't actually transfer the zone. The solutio........
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