• How to configure OpenDKIM on Linux with Postfix and setup bind zonefile


    This guide assumes you have a working Postfix server and want it to sign with DKIM. There are a few things we have to understand to make all of this work though, which require you to be familiar with DNS as well. 1.) Install OpenDKIM apt install opendkim systemctl enable opendkim 2.) Edit /etc/opendkim.conf Syslog yes SyslogSuccess yes Mode&nbs........
  • Debian Ubuntu 10/11/12 Linux how to get tftpd-hpa server setup tutorial


    apt install tftpd-hpa #change TFTP_ADDRESS to by setting address to 192.168.1.1:69 or the IP you need, otherwise it will listen on all IPs and interfaces which could be a security risk. # edit /etc/default/tftpd-hpa TFTP_USERNAME="tftp" TFTP_DIRECTORY="/srv/tftp" TFTP_ADDRESS="192.168.1.1:69" TFTP_OPTIONS="--secure"........
  • efibootmgr: option requires an argument -- 'd' efibootmgr version 15 grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.


    This sometimes happens when trying to install the EFIversion of grub to a device when you are booted into Legacy/MBR mode. It doesn't seem to occur on all machines, but some and seems somewhat BIOS dependent. grub-install --target=x86_64-efi /dev/sda Installing for x86_64-efi platform. grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install.real: warning: Couldn't find physica........
  • 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-........
  • isc-dhcp-server dhcpd how to get longer lease


    You can do a static lease that is tied to the MAC address but what a lot of users prefer is that they come into the office or lab the next day and that their device gets assigned the same IP address (if possible). As we can see in the dhcpd logs that there is threshold that is defaulted as we'll show later. Whatever the threshold is set at, if the lease is younger than the threshold, it will keep the same lease. In other words, if the device goes to sleep or is powered off........
  • qemu-system-x86_64: Initialization of device ide-hd failed: Failed to get


    You start a qemu like this and another VM already started with the same .iso qemu-system-x86_64 -enable-kvm -m 4096 -cdrom some.iso But you get this error: qemu-system-x86_64: Initialization of device ide-hd failed: Failed to get "write" lock Is another process using the image [some.iso]? It's odd because the -cdrom by default is read-only and qemu should not want or care about getting write lock on........
  • How To Stop DNSMasq from listening on all IPs/Interfaces and allow only localhost


    Some people find it less than intuitive to do on DNSMasq and by default DNSMasq is available on 0.0.0.0 which could even be your LAN or Public IP. Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp ........
  • Install Grafana on Linux Debian Ubuntu Tutorial Guide


    First we need a few extra packages: apt update apt install -y adduser libfontconfig1 musl sudo wget https://dl.grafana.com/enterprise/release/grafana-enterprise_10.3.1_amd64.deb Install / Enable Grafana dpkg -i grafana-enterprise_10.3.1_amd64.deb dpkg -i grafana-enterprise_10.3.1_amd64.deb (Reading database ... 44309 files and directories currently installed.) Preparin........
  • 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........
  • vi vim not doing code highlighting E319: Sorry, the command is not available in this version solution


    Normally syntax highlighting is the default behavior. You can enable it manually by hitting :syntax on But normally you'll have this error because of the missing package. E319: Sorry, the command is not available in this version Solution install the vim-gui-common package: apt install vim-gui-common After that you should find that the code is highli........
  • 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://........
  • Docker dockerd swarm high CPU usage cause solution


    If you have swarm services and dockerd is creating a high load even with the containers just being idle, the easiest solution is to upgrade to a newer docker version. For example an identical config of 3 nodes, with Redis 5 with 30 replicas produces a load of about 1.45 in Debian 10 with Docker18.09.1 If I create the same setup on Debian 11, with Docker 20.10.5+dfsg1 then the CPU usage is low. One other difference I wondered is the kernel. In my test setup........
  • 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 Configure NVIDIA GPUs with Docker on Ubuntu: A Comprehensive Guide for AI Deep Learning CUDA Solution


    Welcome to our in-depth guide on configuring NVIDIA GPUs with Docker on Ubuntu. This post is tailored for developers, data scientists, and IT professionals who are looking to leverage the power of NVIDIA's GPU acceleration within Docker containers. Whether you're working on machine lea........
  • Linux Ubuntu Mint how to check nameservers when /etc/resolv.conf disabled solution


    You'll notice that /etc/resolv.conf contains dire warners on most Linux Desktops. # This file is managed by man:systemd-resolved(8). Do not edit. # # This is a dynamic resolv.conf file for connecting local clients to the # internal DNS stub resolver of systemd-resolved. This file lists all # configured search domains. # # Run "resolvectl status" to see details about the uplink DNS servers # currently in use........
  • Docker cannot work on other overlayfs filesystems such as ecryptfs won't start overlayfs: filesystem on '/home/docker/overlay2/check-overlayfs-support130645871/upper' not supported as upperdir


    This does not seem to be officially documented but makes sense that an overlay on an overlay does not work and is considered an unsupported filesystem as is even NTFS . Some admins/organizations try to use ecyptfs as a simple solution to encrypt the contents of Docker. Instead, you could probably........
  • ecryptfs how to manually encrypt your existing home directory or other directory


    Just in case, it is reocmmended to backup the original contents of the directory (especially your home dir) before proceeding. Setup ecryptfs Run this command: ecryptfs-setup-private It will ask you for your login password, this is so that when you login, everything is automatically decrypted by using a passphrase that is wrapped with your login. You can hit enter and leave things blank for an autogenerated passphrase (for mounting) or you can en........
  • Internet Explorer Cannot Download File "Your security settings do not allow for this file to be downloaded." Security Settings Solution


    By default in most newer Windows installs, you will not be able to download files from "Internet" sites and you'll get this error "Your security settings do not allow for this file to be downloaded." Solution to Enable Downloads in IE Internet Explorer 1.) Go to Settings (button) -> Internet options -> Security (tab) 2.) Click "Internet" and then the "Custom Level" button. 3.) Find the following section and set D........
  • Linux swapping too much? How to check the swappiness and stop swapping


    We could always disable swap but this would normally be a bad idea unless you have an incredible amount of RAM and a workload that will never exceed it. However, for live/containerized and high performance environments it could be desirable. Another middle ground may be to set swappiness to a lower number. You may also want to clear your kernel's cache, which could be eating up RAM unnecessarily by c........
  • request_module: runaway loop modprobe binfmt-464c Kernel panic - not syncing: No init found Pid: 1, comm: swapper/0 Not tainted solution


    request_module: runaway loop modprobe binfmt-464c Kernel panic - not syncing: No init found Pid: 1, comm: swapper/0 Not tainted This is usually caused by a mismatch in architecture and happens frequently in development environments. Here is a example of what caused this issue: Your binaries are based on one architecture Your kernel was compiled with another architecture. Why does this happe........
  • How To Add Multiple SSH Keys Ubuntu Mint Linux Debian Redhat


    By default if you create a private key for SSH, it will create something like .ssh/id_rsa Linux will always search for and offer this key when connecting to servers. If you put extra keys in your .ssh directory like id_rsa_realtechtalk.com, they will be ignored by default and NOT used or offered (you can verify this with ssh -v) and see it is not being offered. Here is how you add the extra SSH keys so they are all offered: #this gives........
  • ecryptfs how to change default mount location from Private Ubuntu Debian Centos How


    In a lot of distros like Debian, ecryptfs will mount itself in /home/yourusername/Private This is controlled by Private.mnt which may contain the mount path like this: /home/yourusername/Private Change the default mount location of ecryptfs by modifying this file: home/.ecryptfs/yourusername/.ecryptfs/Private.mnt After you unmount and relogin, you should find ecryptfs is now mo........
  • How to upgrade to the latest Python version on Linux Ubuntu Debian Mint 3.11


    A lot of developers want to go to 3.11 because of the speed improvements, but most distros never have the latest Python version. Using the deadsnakes third party repo is the easiest way aside from compiling it yourself (which is safer and recommended): Step 1 - Add the repo apt-add-repository ppa:deadsnakes/ppa If you get an error about requests then install it:........
  • How to install and configure haproxy on Linux Ubuntu Debian


    haproxy is one of the best known and widely used Open Source load balancers out there and a strong competitor to nginx. haproxy is used by many large sites per Wikipedia: HAProxy is used by a number of high-profile websites including GoDaddy, GitHub,........
  • vagrant install on Debian Mint Ubuntu Linux RHEL Quick Setup Guide Tutorial


    1 - Install Vagrant apt install vagrant Make sure you have a supported Virtualization tool like Virtualbox or VMWare, Hyper-V etc.. It automatically detects and uses what you have. Virtualbox has a lot of support here with tons of images. 2 - Init Vagrant We'll init to have a Debian 10 box by default to show how quick and easy it is. vagrant init generic/debian10........
  • RHEL 8 CentOS 8, Alma Linux 8, Rocky Linux 8 System Not Booting with RAID or on other servers/computers Solution for dracut and initramfs missing kernel modules


    This seems to have changed for RHEL 8 where a normal dracut to update your initramfs creates a system that only boots for the running kernel. For example if you have Kernel 5 and then chroot into a RHEL 8 variant which uses kernel 4.18, and run dracut, it seems that by default the system will be unbootable. It is also the case that if you move your RAID array or drives to another server that it will be unbootable, because dracut seems to only include modules needed for the curre........
  • 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........
  • How To Restore Partition Table on Running Linux Mint Ubuntu Debian Machine


    Here is an easy way to restore things if you have the starting point and size of each partition using fdisk: In this example we pretend that /dev/sda was wiped out, but the running system still has the info in /sys/class/block/sda Go into each partition and record the "start" and "size" hostdev@box /sys/class/block/sda/sda1 $ cat start 2048 hostdev@box /sys/class/block/sda/sd........
  • Debian Ubuntu apt install stop daemon questions/accept the default action without prompting


    This can be a real pain when automating things and you do an apt install and some packages ask a lot of questions. Make sure you set this variable when running: DEBIAN_FRONTEND=noninteractive Remember as well that if chrooting you will want to run like this: DEBIAN_FRONTEND=noninteractive apt install -y yourpackagename ........
  • Grandstream Phone Vulnerability Security Issue Remote Backdoor Connection to 207.246.119.209:3478


    Have you checked your router/firewall logs and disconcertingly see connections to an unknown IP207.246.119.209:3478 from your Grandstream VOIPphones? You're not alone and the Grandstream forums have discussed this issue. However, even their own staff d........
  • Dell PowerEdge Server iDRAC Remote KVM/IP Default Username, Password Reset and Login Information Solution


    Are you new to the company, datacenter or a third party who is responsible for deploying a fleet of servers from scratch. The first step is to normally login to the KVM so you can perhaps manually reinstall, PXE boot the Cloud Image or reimage/reinstall an OS but you need access to the KVM/IP or what Dell calls iDRAC. It's common that you may have forgotten this information or that another employee or colleague has changed the info and did not tell you, that they have left the........
  • Generic IP Camera LAN Default IP Settings DVR


    If you are converting a generic wifi IP camera to ethernet, it may not be that simple as many are default hard coded to a static IP of 192.168.1.168 and login info admin/admin. From there you can login to the camera and assign it to DHCP by going to http://192.168.1.168 For security these cameras +DVR should be on a separate untagged VLAN or if possible a physically isolated non-internet connected switch/network. The reference below is applicable to many of the r........
  • Kazam video blank/high size and not working when recording solution


    By default it uses raw .avi which takes a lot of space and will not play on a lot of systems. It's best to change the codec to something like MP4. Step 1.) File -> Preferences -> Screencast in Kazam Step 2. ) Change Record With: to H264 (MP4) After that you'll........
  • from pip._internal.cli.main import main File "/usr/local/lib/python3.5/dist-packages/pip/_internal/cli/main.py", line 60 sys.stderr.write(f"ERROR: {exc}") from pip._internal.cli.main import main File "/usr/local/lib/python3.5/dist-packag


    Solution for python pip3 not working anymore from pip._internal.cli.main import main File "/usr/local/lib/python3.5/dist-packages/pip/_internal/cli/main.py", line 60 sys.stderr.write(f"ERROR: {exc}") wget https://bootstrap.pypa.io/pip/3.5/get-pip.py python3 get-pip.py DEPRECATION: Python 3.5 reached the end of its life on September 13th, 20........
  • Cisco Switch / Router How To Restore Factory Default Settings


    1.) Make sure your conf register is 0x2102 Do show version and at the very end of the output you will see the Configuration register. show version Configuration register is 0x2102 If the config register is not 0x2102 then enter this command: r1#configure terminal r1(config)#config-register 0x2102 r1(config)#end 2.) Let's Erase the NVRAM/flash........
  • Error opening tftp://10.0.2.2/network-confg (Permission denied) - How To Fix Cisco Router Switch Error Solution Console


    How To Fix This Cisco Switch/Router Error %Error opening tftp %Error opening tftp://10.0.2.2/network-confg (Permission denied) %Error opening tftp://10.0.2.2/cisconet.cfg (Permission denied) %Error opening tftp://10.0.2.2/router-confg (Permission denied) %Error opening tftp://10.0.2.2/ciscortr.cfg (Permission denied) %Error opening tftp://10.0.2.2/network-confg (Perm........
  • CentOS 7 / 8 cannot boot with with mdadm RAID array solution


    This article about migrating to a CentOS 7 /8 RAID mdadm array has a lot of info but I wanted to focus specifically on what newer versions of CentOS 7 require to boot mdadm and what changes are necessary on CentOS 7.8+ CentOS 7 / 8 mdadm RAID booting requirements This assumes you are chrooting into an existing install or using it to get a new deployment ready. However, these steps can........
  • How To Add Default Gateway in Linux using the ip route command routing


    Adding a default route is very simple with this command Just replace 192.168.1.1 with the IPof your GW. ip route add default via 192.168.1.1 How can you delete this default route if you messed it up? It's just the opposite with "delete" instead of add ip route del default via 192.168.1.1 This is the equivalent of the "route command's" route add default gw 192.168.1.1........
  • amdgpu AMD GPU Xorg Won't Start [3576284.324] (EE) Segmentation fault at address 0x0 [3576284.325] (EE) Fatal server error: [3576284.325] (EE) Caught signal 11 (Segmentation fault). Server aborting


    Here is how Ifixed it on a Mint/Ubuntu install 1.) First download the latest AMDGPU-Pro driver from here: https://www.amd.com/en/support Navigate to your relevant video card: 2.) Download the installer One issue is that by default they give you a version for the latest version of........
  • /var/log/journal huge/too large solution in Debian Mint Ubuntu Linux Howot Fix


    Is your /var/log/journal overweight and bloated? For example a decent install of Debian 11 with most applications and services ends up being about 4.9G with the journal taking a few gigs. du -hs /var/log/journal/ 1.3G /var/log/journal/ By default in a lot of distributions there is no maximum size so it will keep growing. This is especially problematic for embedded distributions and devices, but is also a huge waste of sp........
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    Usually LIbreoffice gets it right, but if it opens a normal English CSV as UTF-16 by default and shows Asian languages, you'll have ot manually open to fix it (don't double click the file from the File Manager). Solution - Manually Open the File After Opening LibreOffice Calc You'll see it is defaulting to UTF-16 which breaks everything. ........
  • Debian Ubuntu Mint How To Change Default Display Manager


    The display manager is more so what controls the main graphical login process after Debian/Mint/Ubuntu boot and controls the graphical login sequence. Once you login, you are then usually passed to an Xorg based Window manager like XFCE, Mate, Ubuntu etc... Popular display managers are mdm, gdm, lightdm etc... and they all basically do the same thing with a different interface/style and some feature differences. In Mint for example the normal default display manager is l........
  • Debian Ubuntu Mint DHCP dhclient quits and how to make it persistent if first attempt to get DHCP lease fails


    Debian based OS's have a similar issue as the behavior in RHEL/CentOS dhclient, which is that if you have an interface that relies on DHCP, if the first attempt fails, it will quit and stop. This is a problem especially if you are using your Linux as a router or something else mission critical, but where the internet for some reason may have been down or the DHCP server it gets a lease from broken. The expected behavior you would hope is that when things are back online that the........
  • ssh Too many authentication failures not prompting for password


    If you get this error when trying to SSHto a device or machine and you never even got a password prompt: Too many authentication failures This means that either the remote side is configured for key auth only, OR your client side may be attempting to auth using mulitple keys, and that exceeds the amount of attempted authorizations on the remote ssh server. If the issue is trying to auth too many times which ssh defaults to sending the keys to, you ca........
  • LightDM Mint Ubuntu Debian won't start errors Nvidia Graphics


    This error implies that there may be an issue with Xorg or maybe your NVIDIA GPU cannot start or initialize: 35 laptop kernel: [ 2031.857704] nvidia: loading out-of-tree module taints kernel. 35 laptop kernel: [ 2031.857724] nvidia: module license 'NVIDIA' taints kernel. 35 laptop kernel: [ 2031.857725] Disabling lock debugging due to kernel taint 35 laptop kernel: [ 2031.873280] nvidia: module verification failed: signature a........
  • How To Do Linux Network Bonding Teaming in Mint Debian Ubuntu


    Bonding is an excellent way to get both increased redundancy and throughput. It is similar to the "Network Teaming" feature in Windows. There are a few different modes but we will use mode 6, I think it's the best of both worlds, as it is not just a failover, but it provides round robin, so you will get redundancy and load balancing. So if you have a 1G single port, you will have a combined throughput of 4G at this point. Just bear in mind that the true thr........
  • LXC Containers LXD How to Install and Configure Tutorial Ubuntu Debian Mint


    If you are using mint, delete the preference that stops snap from installing (as it is required for lxc) sudo rm /etc/apt/preferences.d/nosnap.pref 1. Install lxd: sudo apt install lxd Issues install lxd or errors? Click here Debian at this time does not have lxd so you'll need to use snap: sudo apt in........
  • GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox


    This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory. Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage. One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........
  • How To Enable Linux Swapfile Instead of Partition Ubuntu Mint Debian Centos


    This may be necessary if you have a VM or if for some reason you just want to be more efficient with your space and have the flexibility of changing your swap space at will. What we mean is the ability to use a "swap file" or similar to the Windows "pagefile" that normally resides on the root or c: partition of Windows. Here's all you have to do and then you to can have a single partiton with everything, including the swap file on the root partition if you........
  • 404 Not Found [IP: 151.101.194.132 80] apt update Debian 11 Bullseye Solution The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.


    This happens during an apt update and is related to an issue with sources.list, which is particularly troubling, if you are doing a "live-build". P: Configuring file /etc/apt/sources.list Hit:1 http://deb.debian.org/debian bullseye InRelease Get:2 http://deb.debian.org/debian bullseye-updates InRelease [39.4 kB........
  • Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider


    The Best Docker Tutorial for Beginners We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........
  • 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........
  • Linux Debian How To Enable Sudo/Sudoers for User "User not in sudoers file" Solution


    If you get an error that you aren't in the sudoers file, this typically means that your user is not designated as an admin with sudo privileges. In plain English, when it comes to some OS's like Debian including 10,11 etc.., by default the user is created without special privileges which is contrary to how Ubuntu/Mint handle the secondary user. Let's check the sudoers file to see the problem.........
  • Ansible Tutorial - Playbook How To Install From Scratch and Deploy LAMP + Wordpress on Remote Server


    1. Let's work from an environment where we can install Ansible on. If you are using an older version of Linux based on Mint 18 or Ubuntu 16, you may want to get the PPA and get the latest version of Ansible that way: sudo apt install gpg sudo add-apt-repository ppa:ansible/ansible sudo apt update........
  • 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 ........
  • Virtualbox VBOX Howto Port Forward To Guests


    NAT Network, the VMs can communicate but your host cannot access them by default. NAT VMs have internet but cannot communicate with each other. Bridged is simple and allows full LAN access as if you had a physical machine plugged in but is often bad for testing, work or corporate environments and is not very portable when it comes to moving your VMs to other locations and networks. Here is how you can use NAT Ne........
  • How to install Kubernetes with microk8s and deploy apps on Debian/Mint/Ubuntu Linux


    Kubernetes Easy Beginners Architecture Guide Kubernetes is known as container orchestration and we should start at explaining the container part of it. A Container is what runs the actual application and based on an Image, and are more comparable to something like an LXC Container, Virtuozzo/OpenVZ using the Linux Kernel Namespaces feature. Containers run these images as independent, isolated operating environments under the OS's exist........
  • Ubuntu/Debian Linux/Unix Howto Setup Install Syslinux Bootable USB with EFI and MBR from Command Line/CLI Terminal


    There aren't too many simple guides that show you how to use commands to setup your USB or other drive as a normal bootable drive where you can easily boot custom kernels or whatever OS you would like. 1. Get the tools we need: We install "syslinux" for MBR and "syslinux-efi" for EFI and "MBR" as we need a tool that embeds the actual MBR into our USB: sudo apt install syslinux syslinux-efi mbr........
  • Cisco Switch Howto Reset Password


    This was done on a 2900 but applies to all the switches of the same era. Step 1 - Power Cycle and enter recovery mode If you have physical access you can power cycle and hold the mode button down for 15 seconds. After that the SYS light will flash on the switch and you will see the following screenshot. If you don't have physical access (eg. it is a datacenter swich over console only) then power cycle and hit "Ctrl+Pause/B........
  • Cisco Router Password Reset Howto Guide Solution Cannot Login /Unknown Enable Password 2600, 2800, 2900, 3900


    It is common that you may get access to undocumented equipment and need to reset the password. This applies to many Cisco routers whether 2600, 2900, 3900 etc... Cisco's Guide says to hit Ctrl +Pause/Break but if it doesn't work on some devices causing people to say "cisco password reset pause break does not work", you can see Cisco's alternative key combinations here:........
  • VirtualBox VBox Nat Network Handing Out Wrong IP Address Subnet Solution


    This seems to be an ongoing issue that is still reproducable in the latest Ubuntu Vbox 6.x. The default NAT Network range is usually 10.0.2.0/24. If you change this range it does not seem to work properly. Say we change the range to 10.50.1.0/24 If you get a new lease you will find that you get an IP from the old range but the default gateway is from the new range. ........
  • Unable to mount location Failed to retrieve share list from server: Connection timed out - Samba/Linux Filesharing Not working Ubuntu Mint Linux Solution


    So you're trying to browse to a properly configured Samba share but you get this error: Unable to mount location Failed to retrieve share list from server: Connection timed out If your config is right, it can be due to a protocol miss-match where your client has not enabled SMB3 but by default the other side (server) has enabled it. You can test this out to see with the smbclient tool........
  • EFI PXE grub2 Howto guide for Linux EFI PXE Booting on Debian, Mint, Ubuntu, RHEL


    Just a quick note and warning is that if you are testing to see if EFIPXE booting works on a VM, MAKE SURE it actually works. For example Iinitially tested using my Distro's QEMU 2.5+dfsg-5ubuntu10.46 and ovmf BIOS firmware (OVMF supports EFI). However, I found on old versions of QEMU (like 2.5), EFIbooting with GRUB NEVER works so it may appear that you have made a mistake when everything is fine when you boot a physi........
  • Juniper JunOS Command Overview and Howtos Switch, Router, Firewall Tutorial Guide


    Enable "cli" mode equivalent in JunOS cli Configure Mode configure So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure". How Do You Apply Changes You've Made? You can make all kinds of changes to the switch, but remember they are not........
  • Aruba/HP/Dell IAP Wireless Controller Common Default Passwords


    Aruba has a very traditional "admin" for user and password by default for many of its appliances. If you've reset or just got some new units this will be the default password that you should change immediately for security reasons.........
  • Linux Grub not booting the intended kernel solution in Debian, Mint, Ubuntu how to specify which kernel to boot by default


    Traditionally kernels were numbered starting from 0 but by default the "new style" of grub boot loading considers each subkernel item to be different so if you have 3 entries for 4.40-148 rather than counting for 1. To get the expected behavior let's show this example and how we can boot it We do a grep on menuentry in /boot/grub/grub.cfg to see all of the bootable kernels rather than scrolling through loads of extra entries we don't care about (thou........
  • QEMU KVM Keyboard Problems Not Working Right Repeating Characters, Ctrl+C Copy and Paste not working right when using PS2 mouse in guests Solution


    It seems that QEMU/KVM's default PS2 mouse and keyboard doesn't work right in most cases. I have especially observed issues using Ctrl+C and Ctrl+V and in Linux you may see repeated key presses in the terminal and you will wonder why you copied something and it's not in the clipboard when you try to paste. The way to temporarily fix it is to press the key that is repeating once(works in Linux but not really in Windows). Sometimes when moving your mouse it will also s........
  • Mikrotik RouterOS CHR/ISO Basic and Quick Setup Howto Guide


    Many people may not be aware that you can turn commodity hardware into a Mikrotik OS and there are various options which is "CHR" (Cloud Hosted Router) which is a VMimage meant for Virtualization only (seriously, I've tried to dd the image to a physical server and it just crashed as it does not contain any drivers for physical). One note as well if you are trying to do a baremetal install you may get an error "Error Loading Operating System" or........
  • CentOS 7 8 PXEBoot Netinstall Not Working Solution "Pane is dead "new value non-exisetnt xfs filesystem is not valid as a default fs type"


    The problem seems to be that whatever kernel and initrd you have is tied to an old version of CentOS 7 that is no longer in the current repos of most mirrors. If you were previously able to PXEboot and install CentOS and you are sure your network and tftp are good the problem is that you have an outdated kernel and initramfs that point to a defunct version.........
  • Linux How To Stop Missing Drive from Halting Boot Process in fstab


    When you automount a drive in /etc/fstab even if it's not important like an external drive that you only use sometimes and is not required for booting, it will prevent a successfuly boot. If you disable quiet mode for booting you will see something like below "A start job is running for dev-disk ...." How do we fix an fstab entry from preventi........
  • How To Replace Audio Track of Video using ffmpeg


    A very common use case is that you don't want to waste time using a video editor that requires you to open it up and manually import the video clip and audio clip, then manually delete the old audio track and import the video and new audio. That's too much work and time since we don't want to go through the hassle. ffmpeg is our solution, all we have to do is specify 3 variables and we're done! -i Windows2019-Server-Noaudio.mp4 is our in........
  • Linux Mint Ubuntu Debian CentOS Dual Boot Install Issues


    The best way to avoid this problem is to understand how your BIOS is setup to boot. Often newer machines will default to U(EFI) which is different than the traditional MBR/Legacy mode. The problem is that this may not be apparent, often a BIOS Boot Menu will show a Legacy Boot Option and EFIOption without defining it. A good example of this is if your USB is called "Kingston" you may see in your Boot Menu "Kingston" and also "Ubuntu"........
  • Linux Mint Ubuntu Debian Centos RHEL no sound solution


    This assumes your system is a fresh and normally working install. What often happens is that many new devices have multiple audio outputs which are generally analog and HDMI/Digital out. Sometimes the OS defaults to the wrong one that you didn't want. For example if your sound is supposed to play over the HDMI, perhaps the output is set to analog or vice versa.........
  • Linux Mint/Debian/Ubuntu/Centos Installer black grub screen and blank screen after trying to boot installer or main OS


    This happens to a lot of Nvidia users especially users of newer cards like the RTX series. If for example you are trying to boot and install Linux and you get a black and white grub2 screen instead of a nice graphical welcome installer, you probably suffer from this bug. It is normally followed by the user booting and finding they just have a blank/black screen. Here is the quick flow of steps to fix it: If you get a black grub scree........
  • Linux Mint Dual Boot Install Avoid Wiping our your Main C: drive /dev/sda MBR and EFI


    Before you try to install and dual boot it is very important to understand the concept of "what boot mode your BIOS is in" and "what mode you booted the installer to". Then follow the example of Linux Mint (but most Linux installers are very similar)to carefully understand WHERE you are installing your Boot Loader to whether that be MBR or EFI. How Am IBooted? First it's important to check your BIOS to see........
  • How To Get Started on Ubuntu with gpt-2 OpenAI Text Prediction


    apt install software-properties-common add-apt-repository ppa:deadsnakes/ppa apt update apt install python3-pip apt install python3.7 curl gnupg python3.7-dev git ln -s /usr/bin/python3.7 /usr/bin/python3 pip3 install numpy keras_preprocessing curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add - echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel........
  • QEMU-KVM KVM Command Line Practical Guide


    Iam going to build this based on a series of small howto QEMU / KVMposts I've made as I feel much of the information is actually hard to find and piece together from the rest of the web. What I'm going to focus on is how to use virtio as the NIC because if you don't you get very slow NIC speeds but with the virtio NIC model you basically get host speeds. /usr/libexec/qemu-kvm -enable-kvm -smp 8 -m 16000 -net user -net nic,model=virtio -drive file=ubuntu-gpt2l........
  • 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........
  • Asterisk Does Not Retry When Authentication Fails


    When authentication times out that is one thing, but when it just fails like below Asterisk by default will not re-register until you the admin reload the sip or asterisk server: voipserver*CLI> sip show registry Host dnsmgr Username Refresh State&........
  • How To Speed Up Linux Ubuntu and Debian Based Computers By Improving CPU Performance and Changing the CPU Governor


    I used to believe that for Desktops especially that the "ondemand" CPUfrequency changing that kernels included with Ubuntu and Debian based distros have would be sufficient for snappy performance. However, you can feel the lack of performance on the fastest computer if you have ondemand. A lot of times even under high load 100% of your CPUfrequency in MHz will not be used. For example a 2.8Ghz CPUmay only run at 1.8MHz or even .9GHz. Now........
  • How To Install OpenProject on Centos 7 Step-by-Step Guide


    There are a few caveats that may not be obvious to everyone so I am going to cover them here but keep this in mind before starting. Before starting install epel or you will be missing tesseract: yum -y install epel-release #1) When you specify your SSL certificate with a full path, it really needs to exist where you tell it to (including the default location of /etc/ssl/certs and /etc/ssl/c........
  • named bind errors - DNSKEY: unable to find a DNSKEY which verifies the DNSKEY RRset and also matches a trusted key for '.'


    Mar 22 13:46:14 box named[31767]: validating @0x7f51bc001550: . DNSKEY: unable to find a DNSKEY which verifies the DNSKEY RRset and also matches a trusted key for '.' Mar 22 13:46:14 box named[31767]: validating @0x7f51bc001550: . DNSKEY: please check the 'trusted-keys' for '.' in named.conf. Mar 22 13:46:14 box named[31767]: error (broken trust chain) resolving './NS/IN': 192.36.148.17#53 One possibility is sometimes that your time is ou........
  • Radeon R3 GPU on Debian Crashing


    Occasionally my whole screen locks up and I cannot even swith to the console and I find this in my syslog: *-display description: VGA compatible controller product: Mullins [Radeon R3 Graphics] vendor: Advanced Micro Devices, Inc. [AMD/ATI]  ........
  • MySQL 5.7 on Debian and Ubuntu - How To Reset Root Password


    MySQL on Debian versions is configured differently than the native local MySQL plugin so you will be disappointed when your password on the mysql client fails by default. Here is how you reset the MySQL root password the proper and "working way" #first we gracefully stop mysql sudo systemctl stop mysql; #then we forcefully kill any mysqld process just in case sudo killall -9 mysqld mysqld_safe;........
  • Howto Set Static IP on boot in initramfs for dropbear or other purposes NFS, Linux, Debian, Ubuntu, CentOS


    This is only really necessary in the case you don't want DHCP. If you are dealing with an encrypted LUKS server on the internet, you will often want to have a static IP so you know which IP to connect to (or if you have a semi-static IP assigned by DHCP). SET IP Address by /etc/initramfs-tools/initramfs.conf IP Address=192.168.1.27 Gateway=192.168.1.1 Subnet Mask: 255.255.255.0 Hostname=myhome.com IP=192.1........
  • Convert and install to LUKS Encrypted Drive Ubuntu 18.04 19.10 Linux Mint and Debian Based Linux


    The reason for doing this is that the installer doesn't seem to work properly for LUKS and the server installer doesn't even support LUKS anymore. When you use the GUI install on Desktop for LUKS it won't boot and will just hang after you enter your password. So the only reliable way is to do it ourselves. 1.) Make a default minimal install of Ubuntu 2.) Have a secondary disk on the server or VM. 3.)........
  • CentOS 8 how to convert to a bootable mdadm RAID software array


    The cool thing here is that we only need 1 drive to make a RAID 10 or RAID 1 array, we just tell the Linux mdadm utility that the other drive is "missing" and we can then add our original drive to the array after booting into our new RAID array. Step#1 Install tools we need yum -y install mdadm rsync Step #2 Create your partitions on the drive that will be our RAID array Here I assume it is /dev........
  • Linux Mint / Ubuntu / Debian Mate Disable Guest Session and Hide Usernames on Lightdm Login screen GUI


    sudo vi /etc/lightdm/lightdm.conf.d/70-linuxmint.conf Change this: [SeatDefaults] user-session=mate allow-guest=false To this: [SeatDefaults] user-session=mate allow-guest=false greeter-hide-users=true greeter-show-manual-login=true To see and apply your changes just restart light........
  • SSH How To Create Public/Private Key Pair and with a Larger Keysize than 2048 bits


    The problem is that by default ssh-keygen loves to generate an easy to crack 2048 bit key (RSA). Supposedly having a larger keysize helps such as 4096 or 8096 but it is thought to be useless still against Quantum computing. How can I check my existing keysize and type? ssh-keygen -lf /path/to/your/id_rsa.pub The output will be something like below followed by the hash. The first number is the key size and the second part will b........
  • Enable AMDGPU Linux Driver in Debian Ubuntu mint


    To enable amdgpu we have to set special kernel boot parameters. The easiest way is to make it permanent and apply to all kernels (no messing around with grub.cfg) so we'll edit those defaults in /etc/default/grub by changing the GRUB_CMDLINE_LINUX_DEFAULT parameter. After that don't forget to run "update-grub"to apply it (otherwise amdgpu will never be enabled). Requirements No clue really as it really depends. But for example this........
  • 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:........
  • Ubuntu Linux Mint Debian xorg performance and tear-free tuning for AMD Radeon Based Cards


    I find that the default settings for the radeon driver that is applied to most AMD cards is horrible. For example by default TearFree is not enabled and it causes videos to have some kind of square artifacts. Here are the settings I have found most suitable for AMD cards: You need to create file in the following path and restart Xorg or your computer to apply it: *Beware that making a mistake here will possibly make your computer........
  • 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........
  • Centos 7 How to install Mysql/Mariadb


    yum -y install mariadb-server systemctl start mariadb mysql_secure_installation Now we need to secure our install and set the MariaDB root password: The lines you need to act on are marked in bold shown with the answer you need. mysql_secure_installation NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB SER........
  • Linux 3D Performance benchmarks with glxgears 59-60fps solution


    You need to disable vsync like this when running glxgears: vblank_mode=0 glxgears For Nvidia drivers do this: __GL_SYNC_TO_VBLANK=0 glxgears Notice the higher than 59-60 fps results with vblank_mode=0: ATTENTION: default value of option vblank_mode overridden by environment. 7919 frames in 5.0 seconds = 1583.704 FPS 8187 frames in 5.0 seconds = 1637.266 FPS........
  • Linux Ubuntu Debian Centos How To Make a Bootable Windows 7, 8, 10, 2016, 2019 Server USB from ISO


    Use fdisk on your USB drive to create a bootable NTFS partition (in my case /dev/sdb): sudo fdisk /dev/sdb Welcome to fdisk (util-linux 2.27.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): n Partition type p primary (0 primary, 0 extended, 4 free)........
  • Linux Ubuntu Cannot Print Large Images


    If you are using the default "Image Viewer" aka Xviewer it seems to die on very large resolution files. It seems to understand to scale them but the printer will try to print and then fail. Using "Pix" viewer seems to fix this and causes these larger files to print just fine. ........
  • CentOS 6 and 7 / RHEL Persistent DHCP Solution


    It is very silly but the default on the ifup-eth script tells dhclient ( the program that obtains a DHCP IPaddress if you have selected DHCPin your ifcfg-eth* config file) to EXIT / QUIT if the first attempt to obtain a lease fails. No amount of dhclient.conf settings will fix this because if dhclient is started with -1 (which it is by default)then dhclient will quit. This is obviously very bad for MOST cases. Say for example you have a power outage or........
  • Linux tftp listens on all interfaces and IPs by DEFAULT Security Risk Hole Solution


    Just edit your tftp file for xinetd like this: *Change the IPto be the IPof the interface you want to listen on. To test if your tftp is available on a certain IP range use nc -u yourip 69 to see if you can still connect (/var/log/messages or /var/log/syslog) should show the connection if it is open. Oct 13 23:20:34 01 xinetd[26631]: Started working: 1 available servic........
  • python import docx error


    sudo pip3 install python-docx [sudo] password for : Downloading/unpacking python-docx Downloading python-docx-0.8.10.tar.gz (5.5MB): 5.5MB downloaded Running setup.py (path:/tmp/pip_build_root/python-docx/setup.py) egg_info for package python-docx no previously-included directories found matching 'docs/.build' warning: no previously-included files matching '.DS_Store' foun........
  • RTNETLINK answers: Network is unreachable


    This often happens if you are adding a secondary route, especially with Linux source based routing. ip route add default via 10.10.10.254 table 10 RTNETLINK answers: Network is unreachable If that happens you will probably find that it is unreachable because your NIC does not have an IP in the 10.10.10.0/24 range so just assign an IP in that range to your NIC and try again. eg. ifconfig eth0 10.10.10.254 netmask 255.255.255.0 up........
  • nfs tuning maximum amount of connections


    By default at least on Centos 7 nfs only allows 8 connections and starts 8 nfsd daemons. To fix this edit this file:/etc/sysconfig/nfs Edit the line "RPCNFSDCOUNT" (uncomment it so it looks like this: RPCNFSDCOUNT=30 In the example above we are setting 30 nfsd daemons to run (or in other words 30 connections are possible this way).........
  • How To Control Interface that dhcpd server listens to on Debian based Linux like Mint and Ubuntu


    By default your DHCP will often not work because it is not listening on any interfaces. All you have to do is edit this file: vi /etc/default/isc-dhcp-server then find the "INTERFACES" line and add each interface that should listen: INTERFACES="br0 enp0s10" ........
  • LUKS unable to type password to unlock during boot on Debian, Ubuntu and Mint


    I think this is more so an issue with kernel modules not being included. I had this issue on Linux Mint because a new kernel I upgraded to DIDNOT have the "extra" modules and part of that reason is also because older kernels are named differently than new ones. Take this example article below that shows it in action. If you were previously........
  • Wordpress overwrites and wipes out custom htaccess rules and changes soluton


    cat .htaccess RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . index.php [L] I keep reading there is a "# BEGIN WordPress" and a "# END WordPress" in the wordpress htaccess above but there is clearly not. Even more strange is that my permissions are just 444 (read only). so i changed it........
  • QEMU-KVM won't boot Windows 2016 or 2019 server on an Intel Core i3


    CPU:Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz MOBO: Manufacturer: ASUSTeK COMPUTER INC. Product Name: P8H61-M LX3 PLUS R2.0 qemu-kvm-0.12.1.2-2.506.el6_10.1.x86_64 This is weird but the only OS I've found this machine doesn't work with is Windows 2019 Server. Ihave no idea, when 2008, 2012 work f........
  • Bind / named not responding to queries solution


    By default bind will not respond to outside queries for security reasons. In most distributions you will find the default in /etc/named.conf looks like this at the top under options: listen-on port 53 { 127.0.0.1; }; listen-on-v6 port 53 { ::1; }; directory "/var/named";........
  • Linux Mint Mate Customize the Lock screen messages and hide username and real name


    This is a security hole in my opinion and should be plugged by editing the lock screen ui layout: vi /usr/share/mate-screensaver/lock-dialog-default.ui #find these objects and set the visible property to false object class="GtkLabel" id="note-tab-label" object class="GtkLabel" id="auth-username-label> object class="GtkLabel" id="auth-realname-label"........
  • Ubuntu/Gnome/Mint/Centos How To Take a partial screenshot


    By default printscreen or alt print screen will get the whole desktop or the application in focus, respectively. But what if you want to select a portion of the screen? gnome-screenshot: ksnapshot compiz This is a nicely integrated solution sudo apt-get install compizconfig-s........
  • nmap how to scan for all ports and not just the 1000 most common ports


    nmap by default only scans the most common, 1000 ports. How about if you want all ports because some services may be listening on non-standard ports? Just use the -p- switch for all ports or -p1-65535 nmap -p- somehost.com........
  • 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 ........
  • Cisco Unified Communications Manager 12 CUCM 12 - How To Enable Video Calling


    There are multiple layers but most are enabled by default such as the setting in the Phone Device Settings. However the one not enabled by default is the one in "Enterprise Phone Configuration". Enable "Cisco Camera" and then reboot your phones to enable it.........
  • SSH Keep Alive To stop Disconnections


    Are you tired of coming back to your computer only to find your SSH connections have been broken? Even worse are the ones that hang where it appears to be connected but it is really not. The one option you have is an SSHclient side modification to send KeepAlive packets, sometimes this can also keep up your WiFi connection and stop it from disconnecting you as well. To make the keep alive changes for your just yourself (not system wide)........
  • the sign-in method you're trying to use isn't allowed. For more info, contact your network administrator - solution for active directory


    This is usually because the Group Policy forbids that user or group from logging in. run "gpmc" (not "gpedit.msc" as that is for local computer settings when you are not using Active Directory) or go to Administrative Tools and Group Policy Management. Edit the default domain policy like below........
  • Linux bash prompt why does it not show username@host and the current directory?


    Perhaps you've just seen this in the bash prompt: -bash-4.1# Instead of the expected user@hostname# It is probably because you are missing .bash_profile or .bashrc in your home directory Check for yourself: ls -al ~/|grep -E ".bash_profile|.bashrc" -rw-r--r--. 1 root root&nbs........
  • Cisco Switch Setup Guide Command List


    Enter configuration console: enable configure terminal This is important because if your console doesn't look like below none of the commands will work! Switch(config)# Save and Apply Settings wr Show Switch Configuration: show run Show Port List/Sta........
  • Cisco Switch Reset To Factory Defaults


    This works on the 2000 and 3000 series generally. *The easy way is to just hold the mode button for 10+ seconds. The full/proper way is below: 1.) Either power on the unit and hold the "mode" button or hold the "mode" button until you see the below: 00:04:08: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvram 00:04:08: %EXPRESS_SETUP-6-CONFIG_IS_RESET: The configur........
  • Windows Server 2012, 2016, 2019 How To Install and Missing Disabled Telnet Client


    By default telnet is not enabled or installed on the latest Windows servers so you'll get an error saying: telnet is not recognized as an internal or external command dism /online /Enable-Feature /FeatureName:TelnetClient ........
  • Centos 7 Reallocate logical volume space to another


    Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........
  • Using Microsoft's Group Policy Management Editor (GPME) To Change Default Permissions and Internet Explorer Security Settings


    The defaults in Windows 2016 server leave clients crippled so they can't even download basic files or software. But Group Policy Management Editor comes to our rescue! Use cmd or Powershell and run: gpme.msc Choose your domain/computer and then navigate like below and create a new menu entry for IE11 or whatever your version is. Don't be worried if the highest version is IE10 it means that it applies to IE10 AND above.........
  • LVM How To Create Pool (dynamically allocated and not fully allocated)


    The main use I have for this is virtual servers being able to use an LVM volume but not occupying all of the space. It saves time in deploying machines and copying them so you are only copying the space they are using (eg. 5GB / 60GB vs the full 60GB). There are some disadvantages which is mainly the fact that thin pools by their nature allow you to "overallocate" disk space which is that you could use more space than is available on the disk itself and corrupt your data........
  • VMWare Pro Workstation Nic Disconnected and No IP Using NAT


    By default VMWare Workstation often doesn't work as we would like. If you create a VM with a default NAT IP it won't work you will find the NIC is disconnected (even though on the VMWare side it says connected including at Power On). How To Solve It 1.) Create New VMNet for NAT Click "Edit" -> "Virtual Network Editor" Click "Add Network" Select Network To Add "VMNet1" (........
  • Debian 9 SSH root password authentication failure password not working problem / solution


    In Debian a lot of times SSH disables the root user to login by password by default. This means you will get an authentication failure as if you typed in the wrong password. The logs also indicate the password is wrong but what is often the case is in the config file Check /etc/ssh/sshd_config cat /etc/ssh/sshd_config|grep -i permitrootlogin Make sure it says: PermitRootLogin yes If not change it and restart SSH........
  • /etc/iproute2/rt_tables default settings file in Linux Centos 6,7 and most other NIX's


    This should apply to most Linux distributions just incase you get into trouble or wipe out the defaults by accident. /etc/iproute2/rt_tables # # reserved values # 255 local 254 main 253 default 0 unspec # # local # #1 inr.ruhep........
  • Centos 6 / 7 / 8 How To Change Default nameservers in /etc/resolv.conf when using DHCP / dhclient


    First we need to create dhclient.conf if it doesn't exist or edit it: vi /etc/dhclient/dhclient.conf #add this line at the top add the IPs as commas they will be the highest priority nameservers and whatever your ISP gives you will be used after these one (good for DNS backup) prepend domain-name-servers 127.0.0.1,10.10.25.8; After you restart your network or run dhclient again you should see the contents of........
  • 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........
  • 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........
  • 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........
  • Centos 7 - Convert Minimal to Graphical GUI GNOME or KDE Desktop


    Did you just install the minimal version by accident or want to install the GUI? No need to reinstall just tell yum to do the work for you! You could actually have both installed and choose one as your preference on demand (although many people prefer GNOME's simplicity). Step 1.) Install Gnome and/or KDE. To install the GNOME Desktop on Centos 7: yum -y groups install "GNOME Desktop" To........
  • vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down)


    [root@localhost:~] vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down) vsphere distributed switch vmotion not working [root@localhost:~] esxcfg-route -l VMkernel Routes: Network Netmask Gateway Interface&........
  • zenity popup messages, windows, dialogs, error messages calendars and more howto on Gnome Linux including Ubuntu, Linux Mint, Centos and more


    zenity is a nice utility as part of the gnome window manager that allows you to script from bash and retrieve the input from the user. It could also be helpful in just notifying a user when they login with a popup window. I'll give an overview of what's available with zenity: Application Options: --calendar Display calendar dialog --entry Display tex........
  • VMWare Vsphere VCSA Graphical Install Creates json


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


    [root@thetor2017 conf]# service httpd restart Stopping httpd: [ OK ] Starting httpd: WARNING: MaxClients of 3000 exceeds ServerLimit value of 300 servers, lowering MaxClients to 300. To increase........
  • 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........
  • 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........
  • VSphere InternalServerError - Error When Adding Permissions


    InternalServerError (com.vmware.vapi.std.errors.internal_server_error) => { messages = [LocalizableMessage (com.vmware.vapi.std.localizable_message) => { id = vapi.bindings.method.impl.unexpected, defaultMessage = Provider method implementation threw unexpected exception: com.vmware.vapi.std.errors.InternalServerError, args = [com.vmware.vapi.std.errors.InternalServerError] }], data = } I was getting the........
  • 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........
  • 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........
  • Centos PXEBoot NetInstall Failure - Pane is dead


    ValueError: new value non-existent xfs filesystem is not valid as a default fs type Pane is dead From what Iread this is misleading and has to do with the fact that the initrd and kernel are mismatched. This is a hard situation because for some older hardware Iam using the Centos Plus kernel which has modules that Irequire for an older server/NIC. This seems to have cropped up in the past few months and there is no simple fix........
  • Linux Ubuntu Mint Debian cannot play xvid,x264,mp4 or any videos codec issue - xplayer Could not initialize supporting library.


    In xplayer Iget the following error "Could not initialize supporting library.". It actually looks more like a gstreamer issue. For those wondering what the default video player is called it is "xvid" and not "totem" anymore like previous versions. Basically it looks like some codecs are missing when I uninstalled another program it uninstalled other programs and codecs that it shouldn't have. I've tried installing all the gstre........
  • 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/........
  • syslinux / pxelinux how to boot from local drive how to


    Just type the command: localboot By default it will boot the first local drive "0". Ibelieve you can specify a different number to boot a different device. eg. localboot 3 (will boot the 4th BIOS device)'........
  • 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........
  • 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:........
  • PHP geoip.so fatal error Solution


    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 Remove the GEOIP from PHP: php71w-pecl-geoip-1.1.1-1.w6.x86_64 PHP Fatal error: PHP Startup: apc_shm_create: shmget(0, 67108864, 914) failed: Invalid argument. It is possible that the........
  • Linux last command show login by IP instead of hostname


    In the "last" command in Linux by default it will show the information with the hostname (not very useful at all especially since it normally truncates long hostnames). To get last to show the IP address use this: last -i The -i makes it show the numeric IP instead of hostname.........
  • 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........
  • How To Secure Samba NMBD/SMBD to bind to a specific IP address


    By default Samba SMB/NMB listen on ANY and ALLIPs on your system by binding to 0.0.0.0. Obviously this is a huge security risk if you have a public facing server with both internal and external access. Usually when a system administrator sets up a samba server their intention is just to share with a LAN. To do this you need to the following options under the [global] section in smb.conf bind interfaces only = yes interfaces = 192........
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    If you were in my boat you were frustrated that you had to double encode, eg. one separate encode for watermark and a separate from concat and it's not easy to figure out this with ffmpeg on your own. However it is a nice way to save time! ffmpeg -i file1.mp4 -i file2.mp4 -i file3.mp4 -i watermark.png -filter_complex "[0:v]setpts=PTS-STARTPTS[v0]; [1:v]setpts=PTS-STARTPTS[v1]; [2:v]setpts=PTS-STARTPTS[v2]; [v0][0:a][v1][1:a][v2][2:a]concat=n=3:v=1:a=1[v][aout]; [v][3:........
  • /usr/bin/ld: cannot find -lboost_system-mt-s /usr/bin/ld: cannot find -lboost_filesystem-mt-s /usr/bin/ld: cannot find -lboost_program_options-mt-s /usr/bin/ld: cannot find -lboost_thread-mt-s collect2: error: ld returned 1 exit status make: *** [cag


    cagecoin linux compile: sudo apt-get install qt4-qmake libqt4-dev build-essential libboost-dev libboost-system-dev libboost-filesystem-dev libboost-program-options-dev libboost-thread-dev libssl-dev libdb++-dev libminiupnpc-dev Solution: sed -i s/"BOOST_LIB_SUFFIX=-mt-s"/"#BOOST_LIB_SU........
  • ffmpeg Unable to Use Hardware Encoding with Nvidia 3.40 Driver and GT210 card


    I believe from what I've read that this card's driver doesn't support the features after trying all known troubleshooting methods. ffmpeg -i uservideoRendered.mp4 -filter:v hwupload_cuda,scale_npp=w=1920:h=1080:format=nv12:interp_algo=lanczos,hwdownload -c:v hevc_nvenc -profile main -preset slow -rc vbr_hq -c:a copy uservideoRendered.mp4-test ffmpeg -i uservideoRendered.mp4 -filter:v hwupload_cuda,scale_npp=w=1920:h=1080:format=nv12:interp_algo=lanczos,hwdownload........
  • 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........
  • How to change reserved blocks in Linux partition


    user@box:~$ sudo tune2fs -l /dev/md99 [sudo] password for user: tune2fs 1.42.9 (4-Feb-2014) Filesystem volume name: Last mounted on: /mnt/md50 Filesystem UUID: 976a8655-2619-4587-878c-dab07f7b7652 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Fi........
  • Centos 7 Cudaminer Nvidia setup guide


    I am using a GTX 1060 but replace the download for the driver with the correct/current version for your particular card by visiting: http://www.nvidia.com/Download/index.aspx?lang=en-us yum install automake curl openssl-devel libcurl-devel gcc gcc-c++ yum -y install kernel-devel-`uname -r` yum -y install unzip #the........
  • Apache SSL very slow response with Firefox Freezes/Loads Very slow when checking self-signed SSL certificate


    I was sure this was a Centos bug with OpenSSL, Apache, MySQL or even PHP. I tried everything but nothing helped. One clue is that if you check the Apache logs you will see nothing in the access logs until minutes later (this means Firefox has not even passed your request to the remote Apache/htttpd server). When even accepting the invalid certificate message that would show up minutes later when trying to "View the Certificate" Firefox would freeze. This bu........
  • Track 01: 34 of 1726 MB written (fifo 100%) [buf 99%] 3.6x.Errno: 5 (Input/output error), write_g1 scsi sendcmd: cmd timeout after 1.897 (40) s CDB: 2A 00 00 00 44 A9 00 00 1F 00 resid: 6144 cmd finished after 1.897s timeout 40s write track da


    These errors believe it or not are simply because of not being the root user or running with sudo! However if you didn't know to try as root you'd think there was a problem with your burner or disc Essentially it looks like without root you cannot send the required scsi commands to continue writing. Ithink cdrecord should have built-in tests or safeguards to see if it has the permissions to run the required commands. I guess for more advanced users the idea is simila........
  • Linux Mint Install Netboot PXE Guide Howto


    *Update so this doesn't work it must be something to do with the path of nfs or something else but the installer fails with "Installer crashed" at the end whereas with the CD/USB it works. This assumes you've already installed and configured a separate PXE/DHCP server somewhere else and your /tftpboot directory is setup. This is for Linux Mint 18.1 but generally applies to most versions although you may have tro change things like "casper"........
  • 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........
  • Migrating from Linux Mint 17.2 mdadm RAID array to a new one (because I upgraded to larger drives).


    1.) Replicate the number of partitions in your new drives. gdisk /dev/sda gdisk /dev/sdb I created 3 partitions of the same same size. partition #1: +1G (/boot) partition #2: +60G (swap) partition #3: rest of it (/) #note if you are using GPT/gdisk you need to create separate a partition at least 1MB in size (in my case I would a 4th partition and mark it type ef02).........
  • DRBD Split-brain solution


    Uh oh [17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96 [17925926.174325] block drbd0: conn( WFConnection -> WFReportParams ) [17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver [1682]) [17925926.174432] block drbd0: data-integrity-alg: [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........
  • apc_shm_attach: shmat failed: in Unknown on line 0 & apc_shm_create: shmget(0, 67108864, 914) failed PHP Solution


    PHP Fatal error: PHP Startup: apc_shm_create: shmget(0, 67108864, 914) failed: Invalid argument. It is possible that the chosen SHM segment size is higher than the operation system allows. Linux has usually a default limit of 32MB per segment. in Unknown on line 0 PHP Fatal error: PHP Startup: apc_shm_attach: shmat failed: in Unknown on line 0 This error is not at all fun because it actually prevents Apache/httpd from starting or working at all. It will........
  • mdadm kernel panic if trying to change --layout on a RAID10


    It is already known this is not possible mdadm --create /dev/md3 --level 10 --layout=f2 --raid-devices=2 /dev/sdc1 /dev/sdd1 mdadm: /dev/sdc1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 mdadm: /dev/sdd1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 Continue creating ar........
  • mdadm mirrored RAID1 performance using RAID10 -f2 (Far Layout) is the solution


    The only way I've found in mdadm to make 2 drives perform like a proper RAID 1 (eg. the read speed should be 2x that of a single drive) is to use the --layout=f2 (far 2). mdadm raid10 performance issues. Be very aware that mdadm seems to default to layout=n2 (which means near). In this scenario it means it is like mdadm RAID 1 performance (you get maximum read speeds of a single drive). dd if=/dev/md126 of=/dev/null bs=1M cou........
  • Linux How To Recover Partition Table from Kernel and Restore Centos/Debian etc..


    We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe! If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble. Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
  • Linux Mint 17 How to Enable File Sharing Option in File Manager


    I still cannot understand how this would not be enabled by default and I struggled to find the reason why with manually installing samba etc.. wondering why the option for sharing was not in the menu. On Linux Mint "MATE" the package is called "caja-share" and on Cinnamon it is called "nemo-share" so edit the below command as necessary: *Also note that the "samba" package is necessary as it is not inst........
  • Apache Centos Stopping httpd: [ OK ] Starting httpd: [Wed Jun 29 19:29:44 2016] [warn] _default_ VirtualHost overlap on port 80, the first has precedence [Wed Jun 29 19:29:44 2016] [warn] _default_ Virtual


    Stopping httpd: [ OK ] Starting httpd: [Wed Jun 29 19:29:44 2016] [warn] _default_ VirtualHost overlap on port 80, the first has precedence [Wed Jun 29 19:29:44 2016] [warn] _default_ VirtualHost overlap on........
  • HTML files in Apache still displaying as raw text even with DefaultType, ForceType etc.


    There was only one solution here and it was the following: edit /etc/httpd/conf/httpd.conf Comment the lines for the Mime Magic Module: # MIMEMagicFile /usr/share/magic.mime # MIMEMagicFile conf/magic *Don't forget to restart Apache and clear your browser cache twice I was using DefaultType and ForceType a........
  • There was a problem importing one of the Python modules required to run yum. The error leading to this problem was:


    There was a problem importing one of the Python modules required to run yum. The error leading to this problem was: No module named yum Please install a package which provides this module, or verify that the module is installed correctly. It's possible that the above module doesn't match the current version of Python, which is: 2.7.9 (default, Apr 21 2016, 16:51:58) [GCC 4.4.7 20120313........
  • Linksys / Cisco / Grandstream / Polycom PAP2T No delay in dialing recommended fast dial plan


    I modified the default to the following for faster local dialing for North American area codes: (*xx|[3469]11|0|00 [2-9]xxxxxxS0|[2-9]xxxxxxxxxS0|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.) This is what I added to the above: "[2-9]xxxxxxxxxS0" so any 9 digit number is dialed instantly xxx-xxx-xxxx (the S0 at the end makes it dial right away). This makes dialing much quicker and is recommended. *No........
  • Linksys E2500 DD-WRT Upgrade Instructions and Enabling 5ghz with Tomato Firmware


    1.) Flash directly to this file: http://tomato.groov.pl/download/K26RT-N/build5x-132-EN/Linksys%20E-series/tomato-E2500-NVRAM60K-1.28.RT-N5x-MIPSR2-132-Max.zip *I was never able to get the larger "Mega" file to work, at least not initially so I recommend the file above. To enable 5ghz I had to do the "Clear NVRAM" Option before it was shown. 2.) Or if you don't need 5ghz (most devices do not support it and cannot........
  • PAP2T Linksys VOIP strange ring problem


    The problem is that the default of most of these units is set for non-North American phones so the ring sounds like it cuts off and is not sequential. How To Fix the Issue Click on "Regional" and make sure you are in Advanced mode. ........
  • Debian Linux Ubuntu Mint connect to pptp from terminal bash shell


    apt-get install pptp-linux echo "yourvpnusername * yourpasspass *" >> /etc/ppp/chap-secrets vi /etc/ppp/peers/provpnaccounts.com enter (ignore the lines): ============ pty "pptp server.provpnaccounts.com --nolaunchpppd" name testuser #remotename PPTP require-mppe-128 file /etc/ppp/options.pptp ==========........
  • Linux Debian/Ubuntu/Centos How To Force Internet Traffic Through PPTP L2TP OpenVPN Account Only


    The following assumes the computer is local/physical to you and/or it always has a LANIP so it can be accessed on site without having a default gateway. The key to this is not to set a default gateway for your computer or you can set a script on boot or other time to delete the gateway (where eth0 is the NIC you are using): route del default eth0 50.80.20.2 is the VPN server you connect to 192.168.1.1 is your........
  • Centos 6 how to guide convert LVM non-RAID into mdadm 1/10 RAID array live without reinstalling


    Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........
  • Virtualbox errors on Ubuntu/Debian/Mint


    The solution was to reinstall the vbox dkms package and do a manual modprobe of the modules it makes. I never sorted out the unable to start due to the USB issue, I did have the guest additions installed but the only way to boot was to change the pointing device from USB to PS2 and then to disable the USB controller (if your pointing device is set as USB, disabling USB will not work because it will re-enable by default when it sees your pointing device is USB, this is w........
  • OpenVZ Install Guide Again / Quick Setup


    yum -y install wget wget -P /etc/yum.repos.d/ http://ftp.openvz.org/openvz.repo rpm --import http://ftp.openvz.org/RPM-GPG-Key-OpenVZ yum -y install vzkernel vzctl #enable ip_forward sed -i s/'net.ipv4.ip_forward = 0'/'net.ipv4.ip_forward = 1'/g /etc/sysctl.conf #all interfaces should not send redirects echo "net.ipv4.conf.default.send_redirects = 1" >> /etc/sysctl.conf echo "net.ipv4.co........
  • Unable to configure RSA server private key SSL Library Error: 185073780 error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch


    [Tue Jun 23 02:05:52 2015] [error] Unable to configure RSA server private key [Tue Jun 23 02:05:52 2015] [error] SSL Library Error: 185073780 error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch The above is an accurate description of what is wrong. In our case the client made a simple mistake of thinking the localhost.crt and localhost.key (default key locations for Apache SSL in Centos) were in the same directory but they we........
  • Centos OpenDKIM & Postfix Setup Guidel


    #from epel repo yum -y install opendkim chkconfig opendkim on cd /etc/opendkim/keys opendkim-genkey -vd mail.server.com opendkim-genkey: generating private key opendkim-genkey: private key written to default.private opendkim-genkey: extracting public key opendkim-genkey: DNS TXT record written to default.txt ........
  • 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 disable firmware prevents NIC/Ethernet from working phy0 -> rt2x00lib_request_firmware: Error - Failed to request Firmware.


    [ 17.208336] tg3 0000:08:00.0: eth0: Link is up at 1000 Mbps, full duplex [ 17.210194] tg3 0000:08:00.0: eth0: Flow control is on for TX and on for RX [ 76.000065] phy0 -> rt2x00lib_request_firmware: Error - Failed to request Firmware. [ 76.002332] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 86.736004] eth0: no IPv6 routers present [ 148.960038] phy0 -> rt2x00lib_request_fi........
  • VPN Account Buyers Guide and General Info


    What matters most about VPNproviders in 2024? We are highly suspicious of VERYLARGE VPN providers that have LOW PRICES and HUGE DISCOUNTS. The suspicion is that for those who know what costs are involved to purchase thousands of IPs and servers are not small. At the prices that many of the big mainstream providers offer, it is likely unprofitable or barely profitable. Then, how are those companies making money or is that even the goal? There use........
  • cPanel How to set SSL and Dedicated IP in cPanel


    Account Functions -> Change Site's IP Address Choose the domain and then click "Change" Choose the new IP 1.) Setup SSL Certificate in cPanel Click on "SSL/TLS Manager" under the "Security" section. 2.) Under " Private Keys (KEY)" Click "Generate, view, upload, or delete your private keys." Choose "Key Size: 4096........
  • firefox android text size inconsistent large and small text size solution


    This is very annoying and also hard for web developers who want to see how things look on Android. You may be fooled into thinking you have an unclosed bracket or incompatible code but this is the "text inflation feature" which I feel should be disabled by default. It works so inconsitently that one block of text will appear small while the other will be huge and is quite annoying. The solution is simple Settings ->Display and &q........
  • 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........
  • Thunderbird Error An error occurred while loading or saving configuration information for thunderbird. Some of your configuration settings may not work properly.


    This error seems to happen randomly and especially when trying to send e-mails. Apparently it's a long-standing GNome bug but is also partially the default of Thunderbird depending on who you ask. There is no known fix that I'm aware of except to upgrade gnome and the gvfs package but this is not an option for older versions/distributions. An error occurred while loading or saving configuration information for thunderbird. Some of your configuration settings may not........
  • Ubuntu Linux Slow/Delayed SSH ping response Solution


    I've only ever seen this in Ubuntu for some reason and it is because of the /etc/nsswitch.conf settings. So the issue is that if the hostname's reverse DNS cannot be found that you need to go back to DNS which was not the default in this nsswitch.conf file for some strange reason. Edit /etc/nsswitch.conf and replace your "hosts" line with this: #hosts: files dns mdns4_minimal [NOTFOUND=return] mdns........
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    drbd 8.3 hard drive failure recovery drbdadm attach r0 DRBD module version: 8.3.10 userland version: 8.3.8 you should upgrade your drbd tools! 0: Failure: (119) No valid meta-data signature found. ==> Use 'drbdadm create-md res' to initialize meta-data area. ........
  • CPanel mysql root password location how to find


    It is located in /root/.my.cnf This is truly a horrible idea and a security flaw and on top of that MySQL port 3306 is wide open by default with CPanel.........
  • WHMCS Sending Blank E-mails Solution


    After the "latest" update one of our clients asked us to figure out the issue and it turns out it is related to the mail settings. Basically all e-mails were being sent with blank text/no body. The solution Go to "Setup ->General Settings ->Mail" and just click on "Save" and it will work again. Note that this assumes you didn't break things yourself by changing any settings. WHMCS may tell y........
  • 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.........
  • Microsoft Updates suddenly stops at 50% downloading solution


    This seems to mainly affect new installs of Windows and especially on XP randomly. There are whole pages dedicated to the subject but none of them have a simple proper solution. They and Microsoft say to use "Microsoft Fix It", the only problem is it requires .NET and many new installs of Windows don't have it by default. The simple solution you asked for Just reboot Windows and that is how Ifixed it.........
  • Setting Ulimit


    I never found a solution to do it live (nothing worked that I found) so it looks like a relogin is required. Check your maximum file limit cat /proc/sys/fs/file-max 824460 This is different than your actual's user limit which you'll see below ulimit -n 1024 Try and set it higher but it won't work ulimit -n 65000........
  • Centos Howto Upgrade to PHP 5.3 from 5.2


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    This server was experiencing loads of up to 80 and maxing out the RAM and kmemsize on a CPanel VPS. There were literally dozens if not hundreds of exim processes. I have no idea why exim has such a design that would allow it to consume this much CPU and RAM. Any normal MTA should not be spawning so many processes, it should be processing them in sequence and if it is going to spawn hundreds of processes in response to a large volume of mail, it's better to have a delayed del........
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  • mdadm force/fix proper md127 name


    I have an md0 arary that my Centos install refers to. I feel this is half the reason why it won't boot anymore. I saw the initrd for Centos was assembling it as md127 even though it was known as md0. The reason for this is because I used mdadm --assemble --scan to detect the array on a LiveCD. I had no idea this name would stick (but now I realize the name is permanently stored in the metadata once you mount md127 or whatever random name assemble gives it). W........
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  • Canel Default VHOST DocumentRoot/Contents Directory is /usr/local/apache/htdocs


    This can be very annoying and CPanel doesn't seem to document it, or it's not found or made as obvious as it should be. It's always funny when I find it more difficult to work with a control panel than to do everytihng manually without CPanel or even Plesk. So once again, the default serve path for contents is: /usr/local/apache/htdocs and this is especially applicable when accessing Apache by just an IP which is unbound to any domain at this point.........
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    Not sure what rsync switches/options to use? rsync -PDrphogtl The short version would be: rsync -Pha I think these are really common sense options to use and probaby should be the default. Explanation of rsync switches P = display the progress D = hybrid of --specials and --devices so all special and device files will be copied as well. r = recursive (otherwise rsync won't copy files deeper than........
  • Convert HDD/Hard Drive Partition(s) into non-RAID into RAID 1 using existing data without data loss and without reformatting.


    Before we start I take no responsibility for this, you should have a backup and if you make a mistake during this process you could wipe out all of your data. So backup somewhere else before starting this as a precaution, or make sure it's data you could afford to lose. The RAID 1 Setup (Hardware Wise) I've already setup my 2 x 1TB (Seagate) drives with identical partitions, make sure your new hard drive (the empty one) is setup like your curr........
  • Linux EXT3 16GB-17GB maximum filesize issue solved/how to fix


    I have no idea why but mkfs.ext3 defaults to a patheticlly small blocksize of 1024 bytes/1KB (kilobyte). That means the maximum filesize is ONLY 16GB! With 2KB/2048 bytes you get a 256 GB maximum filesize, and with 4KB/4096 bytes you get 2TB! I finally noticed/paid attention to this after realizing that with rsync and scp that no file larger than 17GB could be transferred. I then realized it must be a file size limit on the partition. Here is what tune2fs tol........
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    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........
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    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........
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  • Need identd for port 113 ? Install authd


    Need identd for port 113 ? Install authdyum install authd Happy identing :)Actually it's not that simple. It installs as an "xinetd" service and is disabled and turned off by deafult. To enable it run: [code:1:8c94df8319] chkconfig --level 3 auth on service xinetd restart [/code:1:8c94df8319] This will set identd aka authd to start by default. service xinetd resta........
  • CVSUp the Easy Way


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  • Load Balancing/Clustering


    Load Balancing/ClusteringAn interesting article that discusses the pros, cons and viability of load balancing/clustering http://www.wwwcoder.com/main/parentid/493/site/4189/68/default.aspx ZoneEdit seems to offer an interesting Fail Over Service as well: http://www.zoneedit.com/doc/faq.html#fo........
  • Wireless/xmit power - DD-WRT v23 SP2 (09/15/06) std - build 3932 Linksys WRT54G/GL/GS


    I played around with xmit power (how much power in mW) to see if I could increase the range and signal strength. Idon't think this Linksys WRT54G's strength is the wireless, it seems to have poor signal quality and transfer rates all around. Ithink part of the problem is also that there are several wireless networks around my house that could be interfering and the walls are thick here. Anyaway, moving on now :) The default is 28mW and I increased it to........
  • Apache/Mod_SSL not serving the right/expected certificate?


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  • Create/Enable SSL Certificates for Apache on Linux/Unix Systems eg. Redhat,Centos,Debian


    Shortcut/Easiest Way To Create A Self-Signed Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key Using the above, you instantly create a self-signed certificate valid for 1530 days and you can simply skip to step #5.) below. If You Need a Real SSLCertificate (eg. Equifax/Openssl) then you need to create a CSR request (you'll need to follow Steps 1.) and 2.) in order to create the CSR. You then upload the CSR Certi........
  • iPhone Enable Tethering Manually Update ipcc Carrier Settings/Update via SSH


    Everyone says there is a "manual" way of doing it and then they tell you to use iTunes, but if you're like me, you're travelling on business in a foreign country and your laptop does not have iTunes and you don't have a way of getting it and/or don't want it. For this example I'm using the provider "du" in Dubai, UAE (United Arab Emirates) but this method works for virtually all providers. The requirements in this case to truly "manually update........
  • How to avoid web content hijacking/copying/Force content to be accessed by only 1 domain name


    This is something that happens a lot and it is very dirty, as you probably know each site is hosted on a certain IP address. Sometimes a domain is hosted by a single IP address and the IP address defaults to this very same domain. This means that if someone buys domain abcd.com and enters your IP address (the one of your website) as the A record, your content will show up on their domain as if it was their own. There is an easy way to prevent this by using .htacces........
  • 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........
  • Apache Ignoring/Not processing .htaccess file


    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........
  • 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........
  • 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........
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