fliptoshi

Better SSH Authorized Keys Management

A seemingly common problem that people encounter is how to handle all of your users authorized_keys file.

People struggle over management, ensuring that users only have specific keys in the authorized_keys file or even a method for expiring keys. A centralized key management system could help provide all of this functionality with a little scripting.

One piece of functionality overlooked in OpenSSH is the AuthorizedKeysCommand configuration keyword. This configuration allows you to specify a command that will run during login to retrieve a users public key file from a remote source and perform validation just as if the authorized_keys file was local.

Here is an example directory structure for a set of users with SSH public keys that can be shared out via a web server:

fliptoshi

IP Tables (iptables) Cheat Sheet

IPTables is the Firewall service that is available in a lot of different Linux Distributions. While modifiying it might seem daunting at first, this Cheat Sheet should be able to show you just how easy it is to use and how quickly you can be on your way mucking around with your firewall.

Resources

The following list is a great set of documentation for iptables. I used them to compile this documentation.

• How-To Geek: The Beginner’s Guide to iptables, the Linux Firewall: https://www.howtogeek.com/177621/the-beginners-guide-to-iptables-the-linux-firewall/
• IPTables Essentials: Common Firewall Rules and COmmands https://www.digitalocean.com/community/tutorials/iptables-essentials-common-firewall-rules-and-commands