Getting started with VyOS firewall

This is a super simple command lines to get started with VyOS firewall. In this example, we will create a firewall rule that block every packet coming out of interface eth0 except the client with IP address 172.20.1.11:

1. Create the firewall rule set by name

set firewall name Genius default-action drop
set firewall name Genius rule 1 action accept
set firewall name Genius rule 1 source address 172.20.1.11
commit

2. Apply the rule set to an interface:

set interfaces ethernet eth0 firewall out name genius
commit
save

Reference: https://wiki.vyos.net/wiki/User_Guide#Firewall