::fixture-ready::
$ iptables -S INPUT
-P INPUT DROP
-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -s 203.0.113.0/24 --dport 22 -j ACCEPT
-A INPUT -p tcp -m multiport --dports 80,443 -j ACCEPT
-A INPUT -p tcp --dport 25 -j ACCEPT
-A INPUT -p tcp --dport 5432 -j DROP
::exit-code::0
$ iptables -S INPUT | grep -- '--dport'
-A INPUT -p tcp -s 203.0.113.0/24 --dport 22 -j ACCEPT
-A INPUT -p tcp -m multiport --dports 80,443 -j ACCEPT
-A INPUT -p tcp --dport 25 -j ACCEPT
-A INPUT -p tcp --dport 5432 -j DROP
::exit-code::0