:OUTPUT ACCEPT [0:0]
# otherwise self-referential connections to local host will fail
-A INPUT -i lo -j ACCEPT
+# tolerate any inbound connections requested by our server, no matter the port
+-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
# this enables ping etc.
-A INPUT -p icmp -j ACCEPT
# SSH
-A INPUT -p tcp --dport 22 -j ACCEPT
-# HTTP; uncomment for creating LetsEncrypt certificates in standalone mode.
-#-A INPUT -p tcp --dport 80 -j ACCEPT
# HTTPS in theory, in practice my second SSH port, see sshd_config
-A INPUT -p tcp --dport 443 -j ACCEPT
-# SMTP (allowing for STARTTLS); necessary for mail server to mail server banter
--A INPUT -p tcp --dport 25 -j ACCEPT
-# SMTPS, for mail server to mail user agent communication
--A INPUT -p tcp --dport 465 -j ACCEPT
-# IMAPS
--A INPUT -p tcp --dport 993 -j ACCEPT
-# tolerate any inbound connections requested by our server, no matter the port
--A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
COMMIT
# this last line is here because iptables-restore ignores the final command if no newline follows it
\ No newline at end of file