[LINUX] Limit ssh with iptables for each user

I asked the customer to use a certain server as a general user, but there was a requirement that it should not be used like a stepping stone for ssh, so I responded with iptables.

environment

• OS : ubuntu18.04.3

Limit ssh for each user with iptables

iptables -A OUTPUT -p tcp --dport 22 -m owner --uid-owner {USERNAME} -j DROP

If the LISTEN port of the other server is other than 22, it is meaningless, so please change it as needed depending on the environment.

Persistence of settings

apt install iptables-persistent
/etc/init.d/iptables-persistent save