Linux Firewall Rule Generator
Write your allow rules once, get the equivalent commands for UFW, iptables, and nftables — the three you actually run into across Debian/Ubuntu, older RHEL-family systems, and Rocky 10's modern default.
UFW
iptables
nftables
Test any of these on a console you can't get locked out of before
trusting it on a remote box — an SSH rule with a typo in the
source CIDR is one of the most common ways to lock yourself out
of a VPS.
Enter your rules and press Generate.