Duo offers a relatively simple way to add support Duo two-factor auth to SSH sessions in multiple Linux Distributions. Here are my steps for Ubuntu Server. Create /etc/apt/sources.list.d/duosecurity.list with the following contents:deb [arch=amd64] https://pkg.duosecurity.com/Ubuntu focal main Create a user that corresponds to your username in Duo. Create admin group in Ubuntu.# groupadd admin Add your…
Category: Linux
Enable older SSH key exchange methods
When connecting via SSH to older systems who do not support newer ciphers, you will sometimes get the following error: To permanently enable support for this cipher, you need to add the following line to either/etc/ssh/ssh_config to enable it for all accounts or ~/.ssh/config for just your account. You can change Host * to specify…
Disable the floppy drive module in Linux(Ubuntu)
Sometimes Linux will mistakenly detect a floppy device and create a reference to it because your system does not actually have a floppy drive and you will see errors on the login screen that look similar to blk_update_request: I/O error, dev fd0, sector 0. I find this frequently happens on a VMWare VM. This doesn’t…
Generate Certificate Signing Request (CSR) in Linux
Replace domain with your domain. domain.csr is what is used by your certificate authority togenerate your certificate. domain.key will be used by your web server in conjunction with yourcertificate.
Fix software updates in Cockpit in Ubuntu 20.04
Software updates on the Ubuntu system will fail because Cockpit on Ubuntu doesn’t detect a networkconnection. To fix this, you must use NetworkManager instead of the default networkd. You need to be root or sudo root for all these commands. Edit your netplan file in /etc/netplanand add the following two lines under network:. Remember that…
Expand Logical volume in Linux LVM
LVM makes it easy to resize volumes in Linux. This can be done without unmounting drives orrequiring a restart. First determine the free space of the group volume. Determine the path to the volume group and extend it using vgextend ubuntu-vg /dev/sda3where ubuntu-vg is the group name and /dev/sda3 is a partition created using fdisk….
Install syslinux on Windows Server 2019 WDS
Once Windows Deployment Services is installed and running, locate the folder where WDS is installed.My install is in D:\RemoteInstall. Rename pxeboot.n12 in D:\RemoteInstall\Boot\x64 to pxeboot.0. Rename abortpxe.com in D:\RemoteInstall\Boot\x86 to abortpxe.0. Download syslinux. I used version 5.04. Your mileage may vary with other versions. From the syslinux archive, extract core\pxelinux.0, com32\menu\vesamenu.c32, com32\modules\chain.c32, memdisk\memdisk to D:\RemoteInstall\Boot\x86…
PXE Config examples
I’ve set up a local http web server. You can use another web server mirror if you want.
Set up unattended-upgrades on Ubuntu 20.04
Package upgrades can be set up to install updates on Ubuntu without user intervention. Install unattended-upgrades Install mailx & Postfix If this does not install Postfix, install it now. This will install also install Postfix. mailx is what unattended upgrades uses to send external mail. Configure unattended-upgrades. Edit /etc/apt/apt.conf.d/50unattended-upgrades. This file is mostly self explanatory….
Install GNS3 on UNRAID on your local
network
GNS3 allows network engineers to model networks. Unlike network simulators, GNS3 uses real deviceimages. The devices run on a hypervisor. Unraid is an easy to use NAS operating system based onSlackware that supports docker images and virtual machines. Create a VM in Unraid We will be using Ubuntu 20.04 as the base of GNS3. Install…