IPTables — what is it, have you ever touched it?

IPTables is a utility in Linux for configuring network traffic filtering rules at the kernel level. It allows creating, modifying, and deleting rules that determine which packets to accept, reject, or redirect.

I have used IPTables to configure firewalls, restrict access to services, and organize NAT (masquerading) for containers. For example, you can block incoming connections on a specific port or allow access only from certain IPs.

A basic rule example to allow incoming SSH:

iptables -A INPUT -p tcp --dport 22 -j ACCEPT

IPTables is a powerful tool, but it requires caution, as incorrect rules can block access to the server.