*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
:f2b-sshd - [0:0]
-A INPUT -p tcp -m multiport --dports 22 -j f2b-sshd
-A INPUT -i lo -j ACCEPT
-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -m conntrack --ctstate INVALID -j DROP
-A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 443 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp --dport 587 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -m conntrack --ctstate ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 22 -m conntrack --ctstate ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 80 -m conntrack --ctstate ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --sport 443 -m conntrack --ctstate ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp -m tcp --dport 25 -j REJECT --reject-with icmp-port-unreachable
-A OUTPUT -p tcp -m tcp --sport 587 -m conntrack --ctstate ESTABLISHED -j ACCEPT
-A f2b-sshd -j RETURN
COMMIT