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…
Category: Linux
Useful Tools
Link Compilation Linux Useful Commands
Yarn Repository Expire Key Error
When using yarn through the apt repo, the key might expire, giving you the following error when updating apt. Issue the following command to update the key and then update the repository.
Create a .pfx/.p12 Certificate File Using OpenSSL
Source: https://www.ssl.com/how-to/create-a-pfx-p12-certificate-file-using-openssl/ The PKCS#12 or PFX format is a binary format for storing the server certificate, any intermediatecertificates, and the private key into a single encryptable file. PFX files are usually found with theextensions .pfx and .p12. PFX files are typically used on Windows and macOS machines to import andexport certificates and private keys. Requirements…
DB_VERSION_MISMATCH error when updating AlmaLinux 8 / RHEL 8 / Rocky Linux
When trying to update the operating system, you might receive an error similar to the following … This can be fixed with the following command to remove the existing database …
Add Duo Two-Factor auth to SSH in Ubuntu
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…
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….