Link Compilation Linux Useful Commands Linux Tool Alternatives
Allow SSH connections only from certain addresses using hosts.deny/hosts.allow
This is the method that can be used to allow SSH connections from certain IP networks. An example use for this is allowing SSH from certain public IP networks, as well as from my Tailscale network. If possible, it is probably better to use iptables/nftables/ufw or the firewall feature of your hosting provider if they…
Rate limit connections in Linux
Use the following iptables command to rate limit connections per IP. This is useful for preventing a DDoS attack on DNS servers. However, for DDoS protection for your DNS servers, you should be hosting DNS with the big cloud providers like Cloudflare, or running dnsdist in front of your authoritive servers.
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…
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.
Django Query Sets
More information can be found at the official Django Making Queries documentation.
Python Code Snippets
List of files, just filenames, no directories. List files, no directories, full path. Indicate that your string variable is a raw string. Locate the path of Python you are currently using.
Set git username and email address in Windows / VSCode
After installing Git for Windows, a username and email address has to be set or VSCode will give you the following error: To add your username and email address, open up a terminal. I used Powershell in this case and type in the following commands: If the email address used is also in your GitHub…
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 …