• Linux Debian Mint Ubuntu Bridge br0 gets random IP


    This can break things easily in remove environments where it was normally easy to convert a normal eth0 to a bridge under br0, and that bridge would normally have the same MAC address by default, which is desirable for most situations. In Debian 11 this is different for some reason now. https://unix.stackexchange.com/questions/681013/bridge-gets-random-mac-........
  • nvidia cannot resume from sleep Comm: nvidia-sleep.sh Tainted: Linux Ubuntu Mint Debian


    This seems to happen in many different drivers but it happened more often in newer versions such as 530 vs 525. Then nvidia-modeset goes to 100% There are many reports of this appearing since driver 4.70 and I can confirm I've seen this in various machines. https://forums.de........
  • du - VAS Billing Subscriptions Hack/Scam MLPremiumSub Invascom Astromart Issues Complaint


    If you have du, you may want to check your bill, as you can read about a longstanding issue with fraudulent charges showing up and many users claiming they did not subscribe or solicit those offers. These don't normally show up on new accounts, but they seem to target established users and maybe even users they suspect are not watching their phone or bills, while they are on vacation. These charges can frighteningly happen with 0 interaction from the user despite what........
  • Postfix / sendmail config for DKIM, SPF and DMARC Tutorial Guide E-mail Delivery for Hotmail.com Gmail.com and More HowTo


    This will be the goto to help solve e-mail delivery issues and talk about many practical issues that happen between developers, admins and scripts that send e-mail and do things that may not be acceptable or cause deliverability problems. Sendmail Stuff Edit /etc/mail/sendmail.mc The problem is that if you send directly out from the server using the mail function, the Return-path of the e-mails will be username@thehostnameoftheserver.com. Let........
  • How To Completely Disable ufw in Linux Ubuntu Mint Debian


    This is for the situation that you're doing other things that may conflict or have your own custom rules and ufw keeps overriding iptables. A lot of guides don't work, and even ufw reset does not work, because it still leaves the old ufw chains. Here is what works to disable ufw completely systemctl stop ufw systemctl disable ufw ufw disable rm -f /et........
  • How To Upgrade Debian 8,9,10 to Debian 12 Bookworm


    Step 1.) Upgrade to Debian 11 first The process to go to Debian 12 is not as smooth as 11, when trying to upgrade from Debian 10. In fact, it doesn't work directly, so you'll first need to follow this guide to update to Debian 11, reboot and come back here if successful. Step 2.) Update sources.list Update your /etc/apt/sources.list like this: deb http://........
  • apache2 httpd apache server will not start [pid 22449:tid 139972160445760] AH00052: child pid 23248 exit signal Aborted (6) solution Mint Debian Ubuntu Redhat


    If you get this error, it is often because you have configured Apache with modules that weren't actually installed. Eg. you try to load the PHPmodule but didn't actually install the apache2 php module, so the server can't start. In general, this error can often be caused by issues with problematic modules and/or Apache being configured for modules that have not actually be installed (eg. libapache2-mod-php) is missing. The above results in this less than obv........
  • How To Setup Python3 in Ubuntu Docker Image for AI Deep Learning


    The issue is that Docker images are stripped down, so many tools and even python3 is missing, so you'll have to build or update the actual image yourself. I assume you have started an image with something like this and that you have the Nvidia Toolkit installed (assuming you are using GPUs). If you're not using nvidia just remove --runtime=nvidia --gpus all. docker run -it --runtime=nvidia --gpus all ubuntu bash These works for most images li........
  • Virtualbox Best Networking Mode In Lab/Work Environment without using NAT Network or Bridged


    Virtualbox is a very powerful tool, but for some use cases it is less than optimal. Say you are in a work, lab or other environment where you are not alone on the physical network and there could be overlap of IPs, but you need all of your VMs to be contactable from your host, VMs need to communicate with each other, and VMs need internet. NAT Network will give you VM to VM communication and internet, however, it is buggy and unstable. It also doesn't allow host to VM co........
  • Linux grub not using UUID for the root device instead it uses /dev/sda1 or other device name solution


    You can read lots of posts about this issue but there is not much information about why this is the case or how grub determines the root= device name. Some even suggest modifying grub.cfg manually which is a disaster as the next kernel update will cause grub to revert back to the device name. For most people this won't be an issue but those using template system, automated deployments and working in embedded may run into this issue with custom embedded and created minimal kernel........
  • iptables NAT how to enable PPTP in newer Debian/Ubuntu/Mint Kernels Linux


    Remember that control connections are established on port 1723 and then actual data is transferred over GRE protocol 47. If you have a NAT setup this will work without special forwarding or accepting of GRE packets (normally if you are not blocking outgoing connections and accepting established and related connections). The below two commands will get things going so PPTP and GRE work We first load the ip_nat_pptp module which allows PPTP to work with........
  • Stop ls in Linux Debian Mint CentOS Ubuntu from applying quotes around filenames and directory names


    Later versions of ls try to be helpful and smart to prevent errors in dealing with files with spaces that were tradtionally a pain. However if you need the raw/real filenames, this can break scripts or if you are pasting into a csv etc.... How do you make ls not add the quotes? Add the capital "-N" switch ls -N You could also add an alias to make it more permanent Do this to add it to ~/........
  • docker / kubernetes breaks Proxmox QEMU KVM Bridge VMs


    Docker adds iptables rules that break a lot of things including MASQUERADE or anything that needs the FORWARD table. If NAT is not working after Docker installation, it is probably because it set the iptables FORWARD policy to DROP. This may also make you think that your br0 or bridge is not working, but it's likely just due to what we'll mention later on below, that, Docker probably set your FORWARD chain to default DROP all packets, so nothing on your bridge ever makes it out........
  • How To Tell Which Repository a Package Comes From Debian Mint Ubuntu


    Just use apt-cache policy to find the repo of a package: apt-cache policy lxd lxd: Installed: 3.0.3-0ubuntu1~18.04.2 Candidate: 3.0.3-0ubuntu1~18.04.2 Version table: *** 3.0.3-0ubuntu1~18.04.2 500 500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages &nb........
  • Ubuntu Mint Debian Howto Execute Command / Script / Program Upon Wakeup From Sleep


    Sometimes manual intervention on various Linux system's, including Debian, is required to fix things after waking up from sleep. One persistent issue is the sound system / pulseaudio needing to be reset and not working until you do that after waking up. It's not clear if it's an OS issue itself or the sound driver, but this will fix things. Where do we put scripts or commands that need to be used upon wakeup automatically? /lib/systemd/syst........
  • How To Create OpenVPN Server for Secure Remote Corporate Access in Linux Debian/Mint/Ubuntu with client public key authentication


    Why choose OpenVPN instead of a firewall appliance? OpenVPN can be a reliable and easy replacement for traditional hardware or just be an additional tool that your company uses so that the firewall can focus on its job rather than acting as a VPNappliance at the same time. When comparing OpenVPN with traditional firewal........
  • iptables how to delete rules based on source or destination ip port or just the rule itself


    Let's say we have an IP that is dropped by iptables 192.168.20.2 service iptables status|grep 192.168.20.2 184 DROP all -- 192.168.20.2 0.0.0.0/0 You can use iptables itself like this to list the line numbers: iptables -L --line-numbers Two Ways To Delete The iptables Rule........
  • Proxmox Update Error https://enterprise.proxmox.com/debian/pve bullseye InRelease 401 Unauthorized [IP: 144.217.225.162 443]


    Are you getting this error in Proxmox while trying to apt update or install Ceph? apt update Hit:1 http://security.debian.org bullseye-security InRelease Err:2 https://enterprise.proxmox.com/debian/pve bullseye InRelease 401 Unauthorized [IP: 144.217.225.162 443] Hit:3 http://ftp.hk.debian.org/debian bullseye InRelease ........
  • Linux How To Change NIC Name to eth0 instead of enps33 or enp0s25


    Most newer distros inexplicably cause your NIC to have what Icall "random" non-standard name conventions because of systemd. This is a big problem for many people and especially those running servers. Imagine that you have a static IPconfigured for ens33 but then the hard disk is moved to a newer system, the NIC could be anything from ens33 to enp0s1, meaning that manual intervention is required to go and update the NIC config file (eg. /etc/network/interfa........
  • How To Install NextCloud on Centos 7 and Centos 8


    yum -y install wget unzip wget https://download.nextcloud.com/server/releases/nextcloud-18.0.2.zip unzip nextcloud-18.0.2.zip yum -y install php php-mysqlnd php-json php-zip php-dom php-xml php-libxml php-mbstring php-gd mysql mysql-server Last metadata expiration check: 0:58:02 ago on Fri 13 Mar 2020 02:12:49 PM EDT. Dependencies resolved. ===================================================================........
  • ADATA USB Thumb Drive Issues


    This is the reason that I don't like the new ADATA USB drives such as the UV128/64GB or 128GB drives and other ones that look to be the same style (the green sliding USB connector). They just don't work well from new and never work properly at any point. [ 788.242463] usb 1-1.2: new high-speed USB device number 16 using ehci-pci [ 788.339816] usb 1-1.2: New USB device found, idVendor=125f, idProduct=db8a [ 7........
  • how to use ifplugd in Linux to execute a command or script when a NIC cable is unplugged or plugged in


    It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified. How To Install ifplugd First we install ifplugd sudo apt install ifplugd Let's enable it on our desired device(s) vi /etc/default/ifplugd set this line as so:........
  • Centos 7 Stopped and Disabled Firewalld and ports still blocked


    This is a gotcha but be aware sometimes iptables may be active and loaded by default. Also make sure you don't just disable firewalld but also stop it otherwise it will still block stuff: systemctl stop firewalld If the above is not the issue then it is possible iptables is running and blocking stuff too, so you'll need to stop iptables. So in addition to opening firewalld or disabling it, you would need to disable iptables........
  • Cannot Print PDF Solution and Howto Resize


    If you can print other PDFs but not a particular one it is very likely that the PDF size is A4 (the longer, skinnier Asian paper size) instead of the North American letter size ( 8.5" x 11"). This breaks printing in most cases. Or it may print if you find a program that ignores the size issue. Here is an example of an A4 being rejected by a printer in Ubuntu Linux via CUPS Cannot print PDF CUPS Samsung C460: Processin........
  • Centos 7 how to save iptables rules like Centos 6


    yum install iptables-services systemctl enable iptables service iptables save iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]........
  • qemu-kvm error "Could not initialize SDL(No available video device) - exiting"


    Now older versions of qemu-kvm didn't throw this error say if you just had "-video cirrus" when starting qemu-kvm. But newer versions do care. And this probably only applies to you if you are running from bash/terminal with remote kvm images. What you need to do is remove the "-video" part and just add -vnc :5 eg. this would fix the error: qemu-system-x86_64 -enable-kvm -boot order=cd,once=dc -m 1024 -drive........
  • Debian Ubuntu Mint Howto Create Bridge (br0)


    Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery. To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl". 1.) Install the utilities to make our bridge sudo apt-get i........
  • Virtualbox vbox not starting


    If you've just installed VBox and it is not starting or working, the most common problem is usually that you don't have your kernel source installed, which means there is no kernel driver for vbox so it can't work. You may get an error that says "Kernel driver not installed" in your Virtualbox. So the first thing you should do is install your kernel source by running this: sudo apt-get install linux-headers-`uname -r`........
  • Cisco Unified Communications Manager / CUCM IP 8.6,10,12 Install Error Solution


    Install Errors on Version 12: This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5 on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error. *Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install. What really causes this even though you successfully install........
  • Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM


    The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs. qemu-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........
  • qemu-kvm qemu-system Image format was not specified for '/mnt/space/cucm12.img' and probing guessed raw. Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted. Specify the 'ra


    WARNING: Image format was not specified for '/mnt/space/cucm12.img' and probing guessed raw. Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted. Specify the 'raw' format explicitly to remove the restrictions. #you should manually specify the format q........
  • Centos 6 or 7 no DHCP IP during startup on first boot or reboot solution


    This is usually because of STP causing a delay in the negotiation. Edit your ifcfg script eg: /etc/sysconfig/network-scripts/ifcfg-eth0 Add a LINKDELAY of 30 seconds or whatever works for you: LINKDELAY=30 After that you should have an IP during bootup.........
  • Debian / Mint / Ubuntu net-tools packages provides netstat, ifconfig, route, arp and other classic network admin tools


    The net-tools command brings back all of the oldschool tools that we're used to: /bin/netstat /sbin/ifconfig /sbin/ipmaddr /sbin/iptunnel /sbin/mii-tool /sbin/nameif /sbin/plipconfig /sbin/rarp........
  • SSH proxy/command in the background or from cron script


    If you have an SSHproxy that you need to run automatically from cron you will need it in the background to work. ssh -N -D 22000 user@domain.com Basically the -N let's it continue running in the background.........
  • How To Boot Cisco CUCM UCSInstall 8.6, 10, 11 and 12 on KVM/Proxmox


    The key thing is that you must use a "machine"id of "pc-1.3" or it will say your hardware is not supported. Additionally you MUST use a virtio disk or you will get a ks_pre.sh error as soon as the install starts (a look at logs will show it can't find a disk). This is funny because even though the OS finds the disk and an fdisk -l shows it, it looks like the script looks for a /dev/vda device (virtio) and nothing else, so if you didn't use Virtio as you........
  • iptables linux firewall recommended rules for public computing


    Whether you are at work, at the coffee shop or on the public internet here are some basic but effective rules for iptables that lock things down (eg. no one can SMB or SSH to you or really anything): # Generated by iptables-save v1.4.21 on Fri Dec 14 14:00:08 2018 *nat :PREROUTING ACCEPT [160:19844] :INPUT ACCEPT [4:357] :OUTPUT ACCEPT [2955:182236] :POSTROUTING ACCEPT [2955:182236] COMMIT # Completed on Fri Dec 14........
  • iptables how to log ALL dropped incoming packets


    A lot of people just have a -j DROP to drop all unwanted traffic or traffic not explicitly allowed but there is a better solution if you want real and proper logging: Here is another example of more advanced iptables rules. Take an example iptables rules file -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -i eth1 -p icmp -j ACCEPT........
  • Adobe Acrobat Reader for Linux to use and view XFA Fillable Forms


    The reason for not being able to read one of these dreaded/ fillable "XFA" forms is because no Linux PDF reader that I'm aware of supports them. Part of this reasoning is for security. It is really silly, they should ban these XFA forms or at least replace the Please Wait with the non-fillable version. Download Adobe Reader 9.5 for Linux from here: This is the solution but only so much, at least for me I was able to view th........
  • Debian Linux Mint Ubuntu iptables save and restore settings automatically onboot and reboot


    First you need the "iptables-persistent" package. This gives you an init script that loads your settings from /etc/iptables/rules.v4 and rules.v6 When you install it, it wll save your default setings in /etc/iptables. sudo apt-get install iptables-persistent Remember that the rules are stored here: For IPV4: /etc/iptables/rules.v4 For IPV6: /etc/iptables/r........
  • Why SMART is not smart at all and doesn't properly predict disk errors that cause a kernel panic or crash


    Before getting into the output here is my typical experience with SMART, there is what I call a "bad disk" with pending and uncorrectable sectors that cannot be reallocated. It has caused a kernel panic and system crash repeatedly as we can see from the logs. But SMART says it has "PASSED" its self assessment. SMART is still useful to me but it is more about looking at Current_Pending_Sector. Any time I have had anything but 0 for that attribute it........
  • 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........
  • 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........
  • Linux What is umask (user mask) for file and directory creation permissions and how to calculate umask and change the defaults


    umask are the default permissions that are applied when a file or directory are created. To see this in action simply just "touch filename" or "mkdir somedir" and you'll see what default permissions are applied. The first thing Ialways tell people you should know is to NEVER change the defaults unless you are making them more restrictive. But they work well and if you change the defaults you could end up creating a file without permission to read........
  • 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........
  • Linux Kernel USB Export Errors


    4.374647] usb_common: exports duplicate symbol usb_get_dr_mode (owned by kernel) [ 4.403334] usbcore: exports duplicate symbol __usb_get_extra_descriptor (owned by kernel) [ 4.427736] xhci_hcd 0000:00:15.0: xHCI Host Controller [ 4.427844] xhci_hcd 0000:00:15.0: new USB bus registered, assigned bus number 1 [ 4.429040] xhci_hcd 0000:00:15.0: hcc params 0x200077c1 hci version 0x100 quirks 0x01109810 [ 4.429141] xhci_hcd 0000:00:15.0: cache line size of 64 is not sup........
  • 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........
  • 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........
  • Python SyntaxError: Missing parentheses in call to 'print'


    SyntaxError: Missing parentheses in call to 'print' This is an annoying issue where the syntax betweenPython 2 and 3 changed which breaks old scripts. print "hello" #change to print("Hello, World!")........
  • Ethereum Client Errors


    INFO [07-19|12:11:51] Imported new block receipts count=590 elapsed=8.440s bytes=74117699 number=4870906 hash=6bc60b…934753 ignored=0 INFO [07-19|12:11:57] Imported new state entries count=499 elapsed=9.963ms processed=71076 pending=1526 retry=2&nbs........
  • wodim / cdrecord error cannot burn DVD or BDR .iso Errno: 5 (Input/output error), write_g1 scsi sendcmd: no error


    dvd+rw-mediainfo /dev/sr0 INQUIRY: [ASUS ][BW-16D1HT ][3.00] GET [CURRENT] CONFIGURATION: Mounted Media: 11h, DVD-R Sequential Media ID: RITEKF1&n........
  • iptables guide and examples and howto


    iptables allow port 22 example Of course change --dport and -s to suit your needs #allow certain IP to access port 22 iptables -A INPUT -p tcp -m tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT # block others iptables -A INPUT -p tcp --dport 22 -j DROP........
  • 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........
  • 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........
  • Duplicate entry '2147483647' for key 'PRIMARY' MySQL Error Solution


    This usually happens when you are using something like an INT and try to insert a larger valuethan the maximum which is larger than "2147483647" On a practical term I have seen this and been guilty of this error when using scripts like PHPand generating large random numbers: $hash = mt_rand(5,9999999999999); Obviously that many 9's are more digits than the maximum of an INT resulting in that error. Change your code accord........
  • SMF Forums / Simple Machines Forums Not Displaying Images Theme or Styles Properly using 127.0.0.1


    This is one thing that has me wondering about SMF. It is apparently a known issue but in the latest version and new install nothing looked right because it was using http://127.0.0.1 to find everything! How on earth would it ever do this or think it is normal? Excerpt of crazy html code it produces that causes the issue: ........
  • 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/........
  • iptables v1.4.7: can't initialize iptables table `NAT': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded.


    iptables -t NAT -A PREROUTING -s 24.30.44.0/24 -j DNAT --to-destination 10.10.10.1 iptables v1.4.7: can't initialize iptables table `NAT': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. Solution # it is case sensitive "nat" and DO NOT use "NAT" or you will get this error! iptables -t nat -A PREROUTING -s 24.30.44.0/24 -j DNAT --to-destination 10.10.10.1........
  • kdenlive titles/text renders as white screen when using .sh script


    When using the .sh script the rendering doesn't work after an upgrade of related packages to kdenlive. kdenlive (kdenlive:amd64 (4:17.04.1+git201705191233~ubuntu16.04.1)) with affine or composite transitions was fine but is now broken during the time of transition it is just a white screen. The previous version was fine: kdenlive:amd64 (4:17.04.1+git201705191233~ubuntu16.04.1 But now I can't find it or install it:........
  • 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! If you have trouble booting after this check this CentOS mdadm RAID booting/fixing guide. One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting The nor........
  • Centos/Linux Bash Script Warning when exiting/logging out of bash/shell/terminal for scripts running in the background


    This is mainly the case on Centos but applies to other distros and situations. If you are running programs in the background with the &, at least in Centos it is usually not honored and if you quit or are disconnected the backgrounded programs will be sent sighup and be shut down. The simplest way around this instead of using & is to start any programs or commands with "nohup" Eg. nohup yourscript.sh........
  • Avocent DSR8020 KVM/IP - Network Connect Error - Solution


    This error is commonly due to Java security or TLS settings but there is a second issue with forwarded ports that also causes it. 1. Java Security/TLS Settings issue: This article has the solution to change them all in Linux automatically 2. Port Forwarding Issue if your Avocent DSR is behind NAT/private IP........
  • Centos 7 Migration Guide from Centos 6


    Centos 7 is no cakewalk, there are many fundamental features and basic utilities that are missing or even completely renamed or different! Another shocking thing is to check your NIC it is set by default to not turn on when booting! And by the way there is no more standard eth0 the NIC convention is now "enp0s3" vi /etc/sysconfig/network-scripts/ifcfg-enp0s3........
  • zip warning: name not matched: in Linux Solution


    There are usually two reasons for this. #1 The most common is that you need to enable the -r (recursive) flag with zip to make it recurse into directories. So the solution is to use -r zip -r somefile.zip yourfiles #2 If you are using bash scripting based on ls without the full path or for some other reason the full path is missing, zip looks for the files in the current directory so this will always fail.........
  • PayPal Subscription Howto Creation Automatic Payments Manual


    An easy way to pay companies and friends/family since PayPal does not have an option when sending money to make it a subscription: "business" = The e-mail or PayPal ID of the person/organization to pay to. a3 The recurring amount "eg. 115" will be 115 USD p3 The time period (eg. 2) t3 Unit of time period m=monthly,w=weekly,y=yearly item_name = "the note/product service reason you are paying ha........
  • How to clear all iptables rules for all tables and chains


    iptables -F iptables -t nat -F iptables -t mangle -F This is as simple as it gets.........
  • iptables how to forward localhost port to remote public IP


    iptables -t nat -A OUTPUT -m addrtype --src-type LOCAL --dst-type LOCAL -p tcp --dport 3306 -j DNAT --to-destination ip.ip.ip.ip iptables -t nat -A POSTROUTING -m addrtype --src-type LOCAL --dst-type UNICAST -j MASQUERADE sysctl -w net.ipv4.conf.all.route_localnet=1 Make sure you substitute "ip.ip.ip.ip" for your real public IP and also the "--dport 3306" for the port you want to forward. Finally run the sysctl command and........
  • Centos extremely secure iptables setup


    If you want to make sure only a certain IP can access your server for any service or protocol here is a way to do it (just be sure you have access to the IP(s) mentioned or you will be locked out). iptables -F iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -p tcp -s IP.IP.IP.IP -j ACCEPT iptables -A INPUT -j DROP serv........
  • Apache Vhost HowTo Serve Same Content using a different domain and IP


    There are a few ways of doing this and all basically involve using the reverse proxy or "ProxyPass" feature of Apache to accomplish it. 1.) Create a normal vhost and simply symlink the root directory of the site you want to mirror. Eg. originalsite.com and newsite.com /vhosts/originalsite.com/httpdocs You would symlink like this: ln -s /vhosts/originalsite.com/httpdocs vhosts/originalsite.com/........
  • iptables: Applying firewall rules: iptables-restore: line 40 failed


    service iptables start iptables: Applying firewall rules: iptables-restore: line 40 failed [FAILED]........
  • Centos Add Multiple IP Addresses in a range without manually setting each static IP


    This is actually very simple and this example assumes your network device is "eth0" In Centos your network config would be the following: /etc/sysconfig/network-scripts/ifcfg-eth0 Take the same path and just add a "-range0" So to add a range create the following file: /etc/sysconfig/network-scripts/ifcfg-eth0-range0 IPADDR_START=192.168.1.50 IPADD........
  • bash scripting for loop set number of iterations


    A handy trick in bash that can be adapted to many useful tasks: for i in {1..99}; do echo $i done 1 2.. 97 98 99 100 Another tricky is if you need a 0 in front of the first letters: for i in {1..12}; do if [ $i -lt 10 ]; then i=0"$i" fi echo $i........
  • Bing/Microsoft Ads flex.atdmt.com causing problems for ad tracking and site loading


    I was asked to troubleshoot why a site wasn't loaded or responding properly, it turned out they were using some old javascript tracker from Bing/Microsoft that is no longer valid or working. You have to wait forever for it to time out but it really did disrupt the functionality of a very important site: flex.atdmt.com If you have the above code in javascript on your site remove or comment it out.........
  • Installing zoneminder on Ubuntu/Debian Linux Howto


    sudo apt-get install zoneminder [sudo] password for one: Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libuser-perl python-evince kdebase-apps kwrite unixodbc libgnomeprint2.2-data python-soappy vgabios python-metacity hddtemp python-mediaprof........
  • bash script get directory location and path of script howto tutorial


    So the situaton is this, you depend on things being relevant to where your bash script is and to be safe you want it to be dynamic (eg. do not hard code that we switch to /abc/dir but rather detect where script.sh is located). scriptlocation="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" The path is then contained the the variable "scriptlocation" so you can cd to it in your script etc............
  • Centos/obfsproxy errors


    I never did get it working, it is too bad as obfsproxy should really be an option and integrated into the OpenVPN client and server or something similar: yum -y install python-pip python-devel No package python-pip available. #install the EPEL repo python-pip install obfsproxy python-pip install obfsproxy -bash: python-pip: command not found pip install obfsproxy &........
  • iptables port forwarding multiple ports to another IP


    iptables -t nat -A PREROUTING -p tcp -m multiport --dports 80,443,2068,8192 -j DNAT --to-destination 192.168.1.175 Just adjust the "--dports" to the ports you need and the --to-destination to the destination IP (note it must be on the same network as the server running iptables........
  • bash script check if file exists


    It is very simple and like this to test for the existence of file using bash scripting: if [ -f /etc/somefile ]; then echo "yes it exists" fi........
  • cPanel how to force reinstall rpms and fix packages and other problems caused by updates or duplicate rpms


    If a service is not working and resetting it to defaults is not working and you get bizarre error messages it is probably a broken update and possibly duplicate package. Take in this case "exim" not working even after resetting to defaults. Check for duplicates: rpm -aq|grep exim ........
  • Linux bash how to list files of a certain date with the statu command for scripting


    The command below will show only files created for the month of 2014-12 but you can of course change the year, month or even specific day or time to suit your needs. The awk command simply just makes it output the list of files created on the date you are looking for. stat -c "%z %n" *|grep ^"2014-12"|awk '{print $4}'........
  • OpenVZ vzctl update changes how iptables work - iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. updated solution


    Are you getting the same old error message even though your iptables settings for OpenVZ are correct? iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. The reason is because in newer vzctl the old way of setting IPTABLES="" in vz.conf is completely deprecated (I spent some time fiddling wondering why my settings were correct but........
  • Centos automatic ifcfg-eth0 scripts based on list of IPs from bash


    It's a basic script that reads the file "ips.txt" in the current directory and then creates a corresponding ifcfg file     #!/bin/bash GATEWAY=192.168.1.1 NETMASK=255.255.255.0 device=eth0 counter=0 for ips in `cat ips.txt`; do........
  • /usr/libexec/mysqld: The table 'session' is full solution


    First of all if you're getting this error it is a result of extreme database activity. If you aren't expecting it or it doesn't make sense to you 99% of the time this is a database driven script being exploited (some common examples I see often are things like phpBB being hit by dozens, hundreds or thousands of bots making constant DB write requests). The easiest way to identify this is to restart MySQL and then run the third party tool "mtop" and you'll see all........
  • Openvz iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. solution


    iptables -t nat -A PREROUTING -p tcp -m tcp -d 192.168.2.1/32 --dport 3389 -j DNAT --to-destination 192.168.5.2:3389 iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. The above is often because you don't have the correct modules loaded on the hostnode or enabled for the container but in some cases it's actually a weird openvz setting. Che........
  • PayPal subscriptions automatically cancelling after creation of profile


    There is a weird quirk with how this works, but there is a variable called "src" that defaults to 0 or disabled if not specified as 1. The default 0 means not to recur billing on a subscription.  It's too bad it's not more obvious anywhere nor is there an explanation or warning during payment or after to both the seller and buyer. Here's a proper subscription code example that does recur and does not cancel........
  • 2CO/2Checkout how to create recurring payment subscription button dynamically


    It was hard to find this as I find most online payment processors don't just put the basic information in plain view. Remember to set your sid (your seller id). The below can easily be turned into a scripted PHP template to integrate into your own custom or existing payment solution. http://help.2checkout.com/articles/How_to/How-to-Sell-Recurring-Products-with-2Checkout/........
  • CPanel Link to all of the command line options


    CPanel says you can access 98% of the functions through CLI which experienced Unix/Linux admins prefer for simplicity and for scripting.  I've never found CPanel easy to use from the admin panel, it seems everything is hard to find and a simple task becomes a series of hunts. So for people like me here's the list: http://cpanel.net/system-administrators/command-line-scrip........
  • iptables how to forward port to another IP address with DNAT


    -A PREROUTING -d 98.98.98.5/32 -p tcp -m tcp --dport 1050 -j DNAT --to-destination 192.168.1.50:3389 The above forwards port 1050 on IP98.98.98.5 to 192.168.1.50 port 3389 (you can obviously edit things to meet your needs).........
  • OpenVZ avoid vzctl 4.7 and ploop


    OpenVZ has made vzctl version 4.7 default to using ploop which is a big annoyance.  No one wants it otherwise we'd use Xen or KVM. Make sure to manually specify vzctl 4.6.1 or you will have issues with old scripts breaking since it defaults to using ploop (a single image like Xen/KVM). Here's a list to old versions of vzctl.........
  • OpenVZ mismatched kernel and dev when compiling.


    ./configure ./configure: line 91: cd: /lib/modules/2.6.32-042stab084.25/build: No such file or directory Error: kernel version not found. Please make sure your kernel is configured. dr-xr-xr-x. 4 root root 4096 Feb 21 06:13 .. lrwxrwxrwx 1 root root 45 Feb 21 06:13 build -> ../../../usr/src/kernels/2.6.32-042stab084.25 drwxr-xr-x 2 root root 4096 Feb 12 20........
  • CPanel Apache httpd won't start solution: Starting httpd: Syntax error on line 2 of /etc/httpd/conf/httpd.conf: Invalid command 'Alias', perhaps misspelled or defined by a module not included in the server configuration


    root@hkhosting [/]# service httpd start Starting httpd: Syntax error on line 2 of /etc/httpd/conf/httpd.conf: Invalid command 'Alias', perhaps misspelled or defined by a module not included in the server configuration ........
  • iptables howto multiport forward in single line example


    -A PREROUTING -p tcp -m multiport --dports 10000,18080,13306 -j DNAT --to-destination 192.168.5.83........
  • Fatal error: Out of memory (allocated 6291456) (tried to allocate 7680 bytes)


    Fatal error: Out of memory (allocated 6291456) (tried to allocate 7680 bytes) This is usually caused by Wordpress, Drupal or other ridiculously inefficient CMS' out there, as a temporary fix you can increase PHP's memory limit but it's best to find the actual culprit, by disabling add-ons and other scripts etc...........
  • Asterisk iptables block bruteforce attacks howto with fail2ban


    yum -y install fail2ban vi /etc/fail2ban/jail.conf [asterisk-tcp] enabled = true filter = asterisk action = iptables-multiport[name=asterisk-tcp, port="5060,5061", protocol=tcp] sendmail-whois[name=Asterisk, dest=you@example.com, sender=fail2ban@example.com] logpath = /var/log/asterisk/messages maxret........
  • Update wordpress script


    Requirements: 1.) Enter your root wordpress directory. 2.)Download the latest wordpress.zip to it. #backup your current files just in case cp -a . wp-current-bk`date +%Y%m%d` unzip wordpress-3.7.1.zip rm -rf wp-includes rm -rf wp-admin echo y|cp -a wordpress/wp-includes . echo y|cp -a wordpress/wp-admin . echo y|cp -a wordpress/wp-content/* wp-content echo y|cp wordpress/* .........
  • bash Linux basename and directory name, get the actual directory and file


    Example: basename /var/log/messages messages As shown above the "basename" utility gives you the end filename separately. dirname /var/log/messages /var/log As shown above the "dirname" utlity gives you just the utility even if you pass it a specific file. The above two utilities are very helpful in Bash scripting when working with files and directories co........
  • Openvz OOM Centos Issue Memory Config Settings Solution


    Linux box13. 2.6.32-042stab076.5 #1 SMP Mon Mar 18 20:41:34 MSK 2013 x86_64 x86_64 x86_64 GNU/Linux even setting privvmpages to a specific setting DOES not affect "free -m" in containers. This is probably a kernel issue 23:36:29 up 159 days, 7:12, 4 users, load average: 0.42, 0.44, 0.33 [root@box13 ~]# free -m total&n........
  • PHP5 Centos 6 displays part of code from PHP file for some scripts


    PHP5 Centos 6 displays part of code from PHP file for some scripts Solution edit /etc/php.ini change short_open_tag = Off to: short_open_tag = On Then restart Apache and it should be resolved (assuming the scripts failing used ) ........
  • 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........
  • Unixbench Testing


    The first is a dual CPU AMD Opteron 2373EE (4 cores x 2) and I think it did bad because it has some old 250GB SATAs which can only do about 65MB/s max sequential reads. I think it should have blown away the second (AMD X4 640 Quad Core). [root@fs12home unixbench-4.1.0-wht-2]# ./Run make all make[1]: Entering directory `/root/unixbench-4.1.0-wht-2' Checking distribution of files ./pgms exists ./src exists........
  • 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........
  • pxe-32 tftp open timeout


    pxe-32 tftp open timeout The solution was to enable tftp in xinetd with "chkconfig tftp on". See the troubleshooting below: chkconfig --list NetworkManager 0:off 1:off 2:off 3:off 4:off 5:off 6:off acpid 0:off&n........
  • bash for loop with specific numbers


    Say if you need to make a firewall script to block certain ports this works great. for ports in 21 25 443; do iptables rules here done........
  • iptables centos error getsockopt failed strangely: Invalid argument


    iptables -t nat -A PREROUTING -p udp -m multiport --dports 20,123,443 -j REDIRECT --to-port 53 getsockopt failed strangely: Invalid argument........
  • yum update error


    yum update error Traceback (most recent call last): File "/usr/bin/yum", line 29, in ? yummain.user_main(sys.argv[1:], exit_code=True) File "/usr/share/yum-cli/yummain.py", line 229, in user_main errcode = main(args) File "/usr/share/yum-cli/yummain.py", line 145, in main (result, resultmsgs) = base.buildTransaction() &nbs........
  • Execute Local Bash Scripts remotely by SSH


    for ip in `cat fixlist.txt`; do sudo -u apache ssh root@$ip "`cat iptablesrules.sh`" done In the above example we are going to execute the commands within the local file "iptablesrules.sh" on all the machines in "fixlist.txt". This is a great way of performing server maintenance in a clustered or cloud environment.........
  • 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 SSHinto different servers: Below forwards the port "10001" to the IP192.200.5.53 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 (........
  • WD 20EARX 2TB Bad within days


    This is just trying to read 5GB off the drive with dd and the drive initially tested ok but shortly after I wondered why I was seeing 2MB/s read speeds. Notice the "current_pending_sector", anytime I've seen it at anything above 0 even with no other bad fields/attributes, it means the drive is bad. ata1.00: exception Emask 0x0 SAct 0x3 SErr 0x0 action 0x0 ata1.00: irq_stat 0x40000008 ata1.00: failed command: READ FPDMA QUEUED ata1.00: cmd 60/00:00:........
  • mysql how to execute script from the bash prompt .sql


    mysql -u username --password='yourpassword' ........
  • Linux/Debian shutdown/reboot without going through init force


    -bash-3.1# shutdown -rn now Connection to localhost closed by remote host. Connection to localhost closed. Sometimes I work with embedded systems/custom kernels without any of the fancy init scripts and other common Linux basics that most would expect. This means that often the "reboot" command (which uses an init script) will never work, not only that but it will hang the server and a manual power cycle or reboo........
  • Directadmin error/** Found 7 pre-existing rpmdb problem(s), 'yum check' output follows: e2fsprogs-devel-1.41.12-3.el6.i686 has missing requires of e2fsprogs-libs = ('0', '1.41.12', '3.el6') e2fsprogs-devel-1.41.12-3.el6.i686 has missing requires of l


    Solution To The Following: yum -y install zlib-devel yum -y install e2fsprogs* *** Cannot find /usr/include/et/com_err.h. (yum install libcom_err-devel) *** Installation didn't pass, halting install. Once requirements are met, run the following to continue the install: cd /usr/local/directadmin/scripts ./install.sh Common pre-install commands: http://help.directadmin.com/it........
  • Bad Hard Drive Slows Down Computer


    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........
  • iptables v1.4.10: can't initialize iptables table `filter': Table does not exist (do you need to insmod?)


    I have iptable_filter loaded on the hostnode so I don't understand this issue.........
  • Login and download all files script


    This is very handy if you're too busy and don't have time to download whatever files you need. The -D specifies the domains allowed, this is because I specified -H which means foreign hosts are allowed, if you don't restrict them you'll end up going to the whole internet via ads and other links just like a search Engine would follow. -l 0 specifies to go deep, to as many levels as possible/as exist. -e robots=off is important because robots.txt often says you can't vie........
  • 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........
  • Thunderbird How-To Copy/Backup/Restore Accounts and Settings to Another Computer


    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........
  • bash script remove non-printable special characters/white space


    In bash you test like this for problems that can be caused by non-printable characters since if you don't know how to identify it because it basically breaks your script. echo "url=$url" should print something like this normally if you have properly formatted input/text: url=::http://someaddress.com:: But if you have some weird hidden characters (not visible in a text editor of any sort you'll get something like this ::l=::http://s........
  • iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) - OpenVZ Container Problem iptables module problem solution


    iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) This solution applies to all other iptables modules/problems for OpenVZ, you'll just need to add them to both lists/lines below if you have modules other than what I have below. The modules need to be enabled in both iptables and the OpenVZ hostnode itself and then the containers which need it must be restarted. How To Enable IPTables Modules in OpenVZ........
  • LOG: MAIN PANIC failed to expand condition "${if eq {$authenticated_id}{}{0}{${if eq {$sender_address}{$local_part@$domain}{0}{${if match{$received_protocol}{N^e?smtps?a$N}{${perl{checkbx_autowhitelist}{$authenticated_id}}}{${if eq{$received_prot


    I experienced this with CPanel's Exim after an auto-update (a Google of this error produces lots of complaints with few clear solutions). In this case I'll put the solution at the top. Run /scripts/buildeximconf to rebuild the Exim config and it should be fine after that. mail -vs "from test" user@dest.com < .bash_history LOG: MAIN cwd=/root 4 args: send-mail -i -v user@dest.com LOG: MAIN &........
  • Ubuntu 10 Nvidia Drivers Not Updated After Kernel Update Solution/How-To Manually Rebuild nvidia kernel modules for Ubuntu


    I dread updating the kernel and rebooting to find the Ubuntu graphics aren't working and you have to manually intervene. This is usually because Ubuntu for whatever reason didn't update the drivers you need (eg. the manually compiled Nvidia Kernel driver that MUST be recompiled for each and every kernel update unfortunately). The most common reason may be that "linux-source" hasn't been installed automatically on my system. I tried to manually reinstall the........
  • iptables block torrents/torrenting


    This is a very basic method and won't work in all cases but will reduce the chance of torrenting/abuse by your server users. iptables -A INPUT -p tcp --destination-port 6881:6999 -j REJECT iptables -A OUTPUT -p tcp --source-port 6881:6999 -j REJECT........
  • OpenVPN don't use bridgestart.sh or bridge at all use iptables


    I used the suggested script to bridge from OpenVPN and it took my client's server off-line! Don't ever use their "sample" scripts if you don't have another way of accessing the server than SSH. I actually found it easier to use iptables to tell it to route IPs based on a certain subnet to route through eth0: iptables -t nat -A POSTROUTING -s 192.168.200.0/24 -o eth0 -j MASQUERADE Replace "192.168.200.0/24" with your subnet of cour........
  • gocr - free Linux OCR (Optical Character Recognition) conversion tool


    gocr works great and it's simple, just invoke it like so: gocr filename.png The output will be printed to the screen. My only complaint/concern is that even with standard terminal output (not scanned) from a printscreen, gocr does make mistakes by inserting extra spaces where they don't belong, mistaking letters for numbers etc.. but it's definitely enough to be readable and figure out what you're looking at. I haven't tested yet with scanned input........
  • convert carat ^M/M Windows based text files to Linux


    carat M isn't this symbol ^ that you think, it can only be produced by typing "Ctrl-v, Ctrl-m". That you might see in text files saved from Windows. tofrodos is the package that has dos2unix which is basically the same scripts that replace ^M with /n tofrodos is the Debian/Buntu package name which has the dos2unix and unix2dos binaries........
  • Linux Out of Memory OOM Object Killer Solution "Out of memory: kill process 1955 (sshd) score 81 or a child"


    I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything. I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM. I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives? Also no swap space was ever used! cat /proc/s........
  • Directadmin Solution "This is e-mail notification to warn you that your hostname is setup improperly on your system."


    This is e-mail notification to warn you that your hostname is setup improperly on your system. This is an annoying message and bug with Directadmin, my hostname is set correctly, why does it complain? To get of this message just run this command: /usr/local/directadmin/scripts/hostname.sh yourhostname.com........
  • SPAMASSASSIN/spamcd solution - spamc[16225]: connect to spamd on 127.0.0.1 failed, retrying (#2 of 3): Connection timed out


    May 6 08:16:57 devbox spamc[16225]: connect to spamd on 127.0.0.1 failed, retrying (#2 of 3): Connection timed out May 6 08:17:02 devbox spamc[20214]: connect to spamd on 127.0.0.1 failed, retrying (#1 of 3): Connection timed out spamc[16225]: connect to spamd on 127.0.0.1 failed, retrying (#3 of 3): Connection timed out First make sure that the spamd service is actually running, this is your spamd (spamassassin server) cannot be reached. In my c........
  • encrypt bash scripts to hide source code


    http://www.datsi.fi.upm.es/~frosal/ SHC is a program written by the author above that does just that, it's a great little tool to have. Some have said it isn't exactly encrypting the code but just making it hard to read by obfuscating the code. There was also a good discussion about that here:........
  • Are my WDEARS20 Drives dying already?


    This happened during a RAID array check: SMART says both drives pass the test, but I'm doing a long test on them and hopefully this is not a hardware error. Apr 3 04:22:01 remote kernel: md: syncing RAID array md2 Apr 3 04:22:01 remote kernel: md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc. Apr 3 04:22:01 remote kernel: md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reconstruction. Apr........
  • Drupal 6.2 Install and how to move install to root/non-subdirectory


    drup 6.2 install $cd drupgoodinst3883/ [ drupgoodinst3883]$ ls CHANGELOG.txt cron.php index.php INSTALL.pgsql.txt INSTALL.txt MAINTAINERS.txt modules robots.txt sites update.php xmlrpc.php COPYRIGHT.txt includes INSTALL.mysql.txt install.php LICENSE.txt misc&........
  • Openvz Enable TUN/TAP OpenVPN


    Make sure the module "tun" is loaded on the host. vzctl set 2000 --devnodes net/tun:rw --save *Note what's below is what OpenVZ says you need (but I've never had to do it) vzctl exec 2000 mkdir -p /dev/net vzctl exec 2000 mknod /dev/net/tun c 10 200 vzctl exec 2000 chmod 600 /dev/net/tun On the container test the device: when Something is wrong:........
  • 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..........
  • Failed to save enabled features : The Suexec command on your system is configured to only run scripts under /var/www, but the Virtualmin base directory is /home. CGI and PHP scripts run as domain owners will not be executed.


    Apache/httpd Failed to save enabled features : The Suexec command on your system is configured to only run scripts under /var/www, but the Virtualmin base directory is /home. CGI and PHP scripts run as domain owners will not be executed. This is because I never edited the Apache Config and Virtualmin config to reflect my new/current updated structure.........
  • Plesk: Backup Domains from the CLI - it's quicker


    Plesk 8.6 CLI backup: /usr/local/psa/bin/pleskbackup domains domain.com This is a much better way of doing it and of course it can be scripted, it's a real pain to point, click and wait for Plesk to backup domains (and yes Iknow you could do all of them in a single client file but this is not desirable for my situation).........
  • mdadm Centos 5 automatic resync


    This made me nervous but it's clearly a cronjob based on the messages log that happens every Sunday at about 4:22. I actually can't find any evidence of it in cron.d cron.daily but it is there somewhere obviously. What I don't get is why doesn't this cronjob do a datacheck like Ubuntu's cronscript does? When you unnecessarily rebuild the array you lose your redundancy during that point which makes your data extremely vulnerable. *Update I did a grep of &q........
  • Walmart.ca & Ubuntu Caused Xorg 100% CPU usage


    I can't tell if it's Flash or Javascript that they were using, but it basically caused my sysetm to lockup until I closed that one page. Is this proof enough that Wal-mart is evil?:) I've never seen that before, it's weird how certain things mask themselves as high CPU usage with Xorg, unless it is some kind of weird Xorg problem but I believe it's more of a Flash/Javascript issue from Firefox in Wal-mart's evil scripting.........
  • md: data-check of RAID array md3


    This really made me nervous but notice the mdstat says "check". This is because in Ubuntu there is a scheduled mdadm cronscript that runs everyday on Sunday at 00:57 that checks your entire array. This is a good way because it prevents gradual but unnoticed data corruption which Inever thought of. As long as the check completes properly you have peace of mind knowing that your data integretiy is assured and that your hard drives are functioning properly (I'........
  • yum in Centos 5/Xen halts and exits suddenly


    yum exits in the middle The problem is this VPS seems to be an OpenVZ template from HyperVM. The only way to make it work was to disable i386 packages since this was an x64 kernel. That shouldn't be necessary but it was the only way to make yum stop quitting after the first package or two. I couldn't find any issue by checking the logs either. echo y|yum install vim-minimal telnet expect jwhois net-tools slocate iptables elinks gawk L........
  • Nautilus/GNOME File Manager handy list of extensions


    nautilus-gksu - privilege granting extension for nautilus using gksu nautilus-sendto - integrates Evolution and Pidgin into the Nautilus file manager nautilus-share - Nautilus extension to share folder using Samba nautilus-actions - nautilus extension to configure programs to launch nautilus-bzr - Bazaar (bzr) integration for nautilus nautilus-cd-burner - CD Burning front-end for Nautilus nautilus-clamscan - Antivirus scanning for Nautilus n........
  • Directadmin License Error The ip of this machine (xx.xx.xx.xx) does not match the ip in the license file.
    Check the value of your ethernet_dev=venet0:0 setting in your /usr/local/directadmin/conf/directadmin.conf file and the output of /sbin/ifco


    2010:09:09-22:22:11: The ip of this machine (xx.xx.xx.xx) does not match the ip in the license file. Check the value of your ethernet_dev=venet0:0 setting in your /usr/local/directadmin/conf/directadmin.conf file and the output of /sbin/ifconfig Solution /usr/local/directadmin/scripts/getLicense.sh........
  • Direcatdmin Install AWStats


    cd /usr/local/directadmin/scripts/ scripts]# ./awstats.sh --23:49:28-- http://files.directadmin.com/services/all/awstats/awstats-6.9.tar.gz Resolving files.directadmin.com... 72.35.85.222 Connecting to files.directadmin.com|72.35.85.222|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 1125906 (1.1M) [application/x-gzip] Saving to: `/usr/local/directadmin/scripts/packages/awstats-6.9.tar.gz' 100%[=........
  • DRBD WFConnection Problem/Solution


    This has stumped me a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic,I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work. So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first! Both Nodes Say the Following: version: 8.3.8 (api:88/prot........
  • Openvz Live Migration Error - Error: undump failed: Invalid argument Restoring failed: Error: iptables-restore exited with 2 Error: Most probably some iptables modules are not loaded Error: rst_restore_net: -22


    Adding IP address(es): 192.168.5.8 192.168.5.9 Setting CPU units: 1000 Error: undump failed: Invalid argument Restoring failed: Error: iptables-restore exited with 2 Error: Most probably some iptables modules are not loaded Error: rst_restore_net: -22 Container start failed Stopping container ... Container was stopped Container is unmounted Error: Failed to undump VE Resuming... vzquota : (erro........
  • OpenVZ iptables v1.3.5: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded. Solution


    This error is annoying, in a Virtuozzo KB entry about this ip tables nat problem they say the kernel needs to be ugpraded: Symptoms The node runs 2.6.18-x kernel older than 2.6.18-028stab053.10. NAT module does not work in container, you get "can't initialize iptables table 'nat'" error: # iptables -t nat........
  • mdadm when a RAID 1 member dies


    [27969.398749] sd 5:0:0:0: [sdb] 3907029168 512-byte hardware sectors (2000399 MB) [27969.398749] sd 5:0:0:0: [sdb] Write Protect is off [27969.398749] sd 5:0:0:0: [sdb] Mode Sense: 00 3a 00 00 [27969.398749] sd 5:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [27972.117543] ata6.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x0 [27972.117543] ata6.00: irq_stat 0x48000000 [27972.117543] ata6.00: cmd 60/08:00:ff:7........
  • 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........
  • Use rcconf to edit startup/init.d/init scripts on Debian/Ubuntu based distributions


    I've never understood how to enable and disable services for different run levels in Debian based distros, it's just weird, annoying and doesn't make sense. I much prefer chkconfig from RHEL. Just install the package called 'rcconf' and be done with it. rcconf makes things easy for you. apt-get install rcconf Reading package lists... Done Building dependency tree Reading state information... Done........
  • Centos How To Add Static Network Route


    route add -net 192.16.5.0 netmask 255.255.255.0 eth0 Of course adjust as you need (eg. the 192.16.5.0 should be changed to the subnet you need access to and eth0 should be changed to the network device that you want that subnet routed through). I also use the /etc/sysconfig/rc.local script and add the above into it (remember that this route only gets added AFTER all other init scripts have finished though).........
  • How To Set DHCP/Static IP Address in Centos/RHEL/Fedora & Debian/Ubuntu/Kubuntu/MEPIS Set DHCP/Static IP Address


    Basically the two main types of distros are Debian and RHEL/Centos based. I'm just going to give a quick overview of how the configuration of IP interfaces works in Debian/Centos based distros. *Just one thing to remember, when setting IPs statically you have to manually specify a DNS server in /etc/resolv.conf (since DHCP is what normally does it automatically) Debian/Ubuntu/Kubuntu/MEPIS The IP (DHCP &........
  • CPanel Use /scripts/easyapache to recompile Apache/PHP with different options


    I used the "Image Manipulation and Security Options" and let the script do the rest. /scripts/easyapache For whatever reason, doing a manual compile of PHPmyself broke everything and I've never seen that before, that's why I resorted to the cheat of easyapache.........
  • Openvz Enable Most Common iptables modules


    The default options for iptables are very basic. Here is what you need to do in order to enable them in OpenVZ. 1.) Add the modules to iptables and restart iptables: vi /etc/sysconfig/iptables-config Edit the line as so: IPTABLES_MODULES="ipt_REJECT ipt_tos ipt_TOS ipt_LOG ip_conntrack ipt_limit ipt_multiport iptable_filter iptable_mangle ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_length ipt_state iptable_nat ip_nat_ftp" 2.........
  • Unixbench Score on Core i5 750 with OpenVZ Kernel vs Xen/Openvz


    This was unbelievable how much the Xen kernel slows things down, keep in mind both tests were done on the hostnode, one was with the Openvz-Xen hybrid kernel and the other was just OpenVZ. You can see the performance difference is nearly 300% better when not using the Xen kernel. OpenVZ-Xen Kernel Test Results (I was wondering what was wrong/so slow with my Core i5!) # # # # # #&n........
  • Seagate Drive 500GB Drive Dying


    This drive is clearly on the way out, the Kernel knows it but I'm surprised that SMART is not concerned. I didn't blame Seagate for their past issues until now. This hard drive has hardly been used and has not even been powered on for a year according to SMART. Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Model Family: Seagate Barracuda 7200.11 Device........
  • PDF File Conversion/Solution Using Imagemagick to create PDF files for free, quickly and efficiently


    I'm really starting to love ImageMagick, I've used it to mass convert/resize family photos with scripts and all kinds of handy things. Today I just learned that you can create PDF files with it too, say if you have images scanned or anything else it's very simple: convert *.jpeg output.pdf You can replace jpg with whatever format your files are in. One thing to remember is that you can specify the order that the images/pages are added to the PDF manu........
  • email2fax and Asterisk to do eFaxing


    It's basically free bash shell script available from: http://wpkg.org/email2fax/index.php/Main_Page Make sure you have the required tools: libtiff ghostscript mpack/munpack Where you can e-mail your Asterisk box and it will fax it to the phone number in the subject line. The good news ends there, it is fairly undocumented and buggy. Take for example how the documentation mentions you can invoke from the com........
  • 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........
  • Compaq V2405CA Laptop - Unixbench Performance Test


    Here are the results, it is Sempron 3000+ AMD Mobile, 500Gig HDD, 512MB RAM with shared ATI Radeon graphics. # # # # # # # ##### ###### # # #### # # # # ## # # # #&nb........
  • PHP cannot access /usr/bin/openssl


    PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........
  • rsync bash script


    rsync bash script [code:1:722d8a25c1]#!/bin/bash # config --------------------------------- # two methods # from = receive data from another server # to = send data to another server rsync_method=from rsync_ip='192.168.5.18' local_dir='/home/backupguy/backups' remote_dir='/home/backup' free_space_bin='/home/backups/freediskspace.sh' # config end ------------------------------ if [ '$rsync_me........
  • JavaScript get valued of selected <select> drop down l


    JavaScript get valued of selected drop down l [code:1:4be190f44a]Package = OrderForm.package.options[OrderForm.package.selectedIndex].value;[/code:1:4be190f44a] OrderForm = Name of HTML form the SELECT is inside package = Name of SELECT element eg. JavaScript says form name is not defined even though it is I've integrated this into my design and I got an error saying the Form Name i........
  • Javascript Get a specified element using getElementById()


    Javascript Get a specified element using getElementById()Great, it produces the value for whatever "id" is passed to the function. http://www.java2s.com/Code/JavaScript/Development/GetaspecifiedelementusinggetElementById.htm [code:1:1287ede953] function getElement(){ var x=document.getElementById("myHead........
  • JavaScript how to do math arithmetic with floats and int


    JavaScript how to do math arithmetic with floats and intI have 3 variables some of which are just int and some float and need to find their sum It just adds them as strings for some reason.Normally this would work but the floats were actually text technically I guess since they came from a form. You need to convert them using parseFloat() and then everything is fine.........
  • JavasScript how to set or write value in id tag


    JavasScript how to set or write value in id tagbla I need to set a value inside that DIV tag using Javascript, how would I do it?Doesn't work for me: [quote:c6b5f693a5]Warning: Element referenced by ID/NAME in the global scope. Use W3C standard document.getElementById() instead. Source File: http://hosting.com/vps-order.html Line: 19[/quote:c6b5f693a5] [code:1:c6b5f693a5]........
  • Javascript round float to 2 decimal places


    Javascript round float to 2 decimal places[code:1:7d628eaf94] totalprice = Math.round(totalprice*100)/100;[/code:1:7d628eaf94] substitute the second instance of totalprice with the variable that needs to be rounded to 2 decimal places........
  • Javascript window.onLoad


    Javascript window.onLoadThis can be used anywhere on an HTML page, my favorite (since body onLoad is not an option for me) is to use: window.onLoad = functioncall(); Eg. to calculate the value of a form, you want to use the onLoad at the end of the form, as things are called in order of course........
  • Photoshop Save Layers as a file


    Photoshop Save Layers as a fileJust click: [quote:64c0c64b5a]File: Scripts: Export Layers to Files[/quote:64c0c64b5a] You can choose an individual layer or all of them. Have fun :)........
  • Setup Static IP Address ONBOOT


    Setup Static IP Address ONBOOTAssuming you are using eth0 Note this will work for any version of CentOS and basically any version of Redhat Linux or Redhat based distribution. You would need to create a new file [code:1:02f8d34c30] /etc/sysconfig/network-scripts/ifcfg-eth0:0[/code:1:02f8d34c30] DEVICE=eth0:0 the ":0" at the end specifies alias 0 we could actually change this to ":99" or "........
  • Updated to Version 3.8 and can't login


    Updated to Version 3.8 and can't loginSSHD accepts my password but then hangs at "Last login: Wed Sep 13 21:30:02 2006 from" This occurred during a yum update after upgrading my release, installing the new kernel and rebooting. I got kicked out of sshd after seeing the following during yum update: telnet 100 % done 85/476 tux 100 % done 86/476 ntsysv 100 % done 87/476 rpmdb-redhat 94 % done 88/476........
  • Become your own ISP!


    Become your own ISP!http://waverider.com/ I would link to the exact product I am mentioning but it's under Products/5.8Ghz because I can't find the exact URL because of their annoying javascript and frames (you'll see what I mean). The exciting thing is that this unit can supposedly be up to 72mbit, it is NOT line of sight and the range is up to 20miles. I wonder how real world speeds and range would actually be and if it is reliable. I j........
  • Backup Shell Script


    Backup Shell Script[quote:aaa4b0b165]#!/bin/sh date=`date -I` mysqldump --all-databases | gzip > /var/backup/backup-$date.sql.gz [/quote:aaa4b0b165] Something like that could be useful as a cronjob to locally or remotely backup your databases........
  • Server Uptime Script


    Server Uptime ScriptA cool and free tool for uptime! http://checkwebsite.org/........
  • Bash Script Info


    Bash Script Infohttp://www.faqs.org/docs/Linux-HOWTO/Bash-Prog-Intro-HOWTO.html#ss10.5 http://www.scit.wlv.ac.uk/~jphb/spos/notes/shell/shell5.html http://quong.best.vwh.net/shellin20/#LtohTOCentry-41 http://www.cactus.org/~dak/shellscript.html http://db.ilug-bom.org.in/Documentation/abs-guide/ http://pegasus.rutgers.edu/~elflord/unix/bash-tute.html http://heather.cs.ucdavis.edu/~matloff/UnixAndC/Unix/CShellII.html Since bash i........
  • Linux Kernel Compilation (Intel(R) 82575/82576 PCI-Express Gigabit Ethernet support ) Error - drivers/net/igb/igb_main.c: In function `igb_up': make[3]: *** [drivers/net/igb/igb_main.o] Error 1


    Linux Kernel v2.6.30.3 102220 blocks CHK include/linux/version.h CHK include/linux/utsrelease.h SYMLINK include/asm -> include/asm-x86 CALL scripts/checksyscalls.sh CHK include/linux/compile.h CC drivers/net/igb/igb_main.o drivers/net/igb/igb_main.c: In function `igb_up':........
  • Unixbench Score with Glusterfs/Openvz & Quad Core Xeon - Updated with GlusterFS 2.0.8


    You might remember my original GluserFS/OpenVZ benchmark which produced a horrible 29.8 This is the exact same system, but using the latest 2.0.8 (with some small files patch which speeds up performance) you can see it is about 25% faster. I also haven't tuned my config files at all, but there are some settings that should increase performance on small files which I believe i........
  • 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 HNitself 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........
  • Have an OpenVZ VPS/Linux Virtual Private Server and nothing works right?


    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........
  • MySQL Restoring And Dumping/Backing UP MySQL Data/Tables/Databases


    Backing MySQL Databases Backing Up/Dumping All Mysql Databases To A Single File mysqldump --all-databases -u admin -p > allmysqldatabases.sql The "-all-databases" clause is pretty obvious isn't it? It means that it will backup all databases. The "-u admin" means login using the user "admin", if you h........
  • 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 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........
  • OCFS2 crash


    When trying to even cd or ls the mounted OCFS2 partition it crashes. Ithink this is a combination of VMWare Server's problem and the way I mounted and symlinked to it. More than anything this shows the problem and lack of forsight with VMWare, but also that OCFS2 is easily crashed if you do strange things. Output of /var/log/messages for OCFS2 Apr 10 15:57:45 localhost kernel: [84331.691258] Modules linked in: vmnet vmci vmmon ocfs2_stac........
  • Bash Scripting Variable Scope Using Piped While Loop


    I've been struggling with this for awhile, wondering why all of my variables are null. Ijust realized the variables disappear after leaving this while loop. Note that I'm piping to the while loop which makes a subshell Ibelieve which is the cause of the issue: echo "$accounts"|while read thisline; do somevariable="some value" (( ++counter )) done At all costs you ne........
  • Writing/Burning a data CD-R/DVD-R or DVD+RW in Unix/Linux


    There's a lot of outdated information and confusion for system administrator's out there. One annoying task for many an Administrator has been backing up data in Linux. You don't need any GUI tools such as K3B or GnomeBaker. Both are excellent tools but for veteran command line users working remotely, using the keyboard is a great and possibly automated way to save yourself pain and hassle. At a later date we'll cover how scripting can automatically backup certain........
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