Disable all the mail protocol by iptables

Disable all the mail protocol by iptables:

iptables -A INPUT -p tcp -m multiport --dport 25,110,465:587,993:995 -j DROP
iptables -A INPUT -p udp -m multiport --dport 25,110,465:587,993:995 -j DROP
iptables -A OUTPUT -p tcp -m multiport --dport 25,110,465:587,993:995 -j DROP
iptables -A OUTPUT -p udp -m multiport --dport 25,110,465:587,993:995 -j DROP

save the iptables:

iptables-save
service iptables save