5 # otherwise self-referential connections to local host will fail
6 -A INPUT -i lo -j ACCEPT
7 # this enables ping etc.
8 -A INPUT -p icmp -j ACCEPT
9 # tolerate any inbound connections requested by our server, no matter the port
10 -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
12 -A INPUT -p tcp --dport 22 -j ACCEPT
13 # SMTP (allowing for STARTTLS); necessary for mail server to mail server banter
14 -A INPUT -p tcp --dport 25 -j ACCEPT
15 # SMTPS, for mail server to mail user agent communication
16 -A INPUT -p tcp --dport 465 -j ACCEPT
18 -A INPUT -p tcp --dport 993 -j ACCEPT
20 # this last line is here because iptables-restore ignores the final command if no newline follows it