*filter
# Allow all loopback (lo0) traffic and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT
# Force SYN packet check
-A INPUT -p tcp ! --syn -m state --state NEW -j DROP
# Force fragmented packet check
-A INPUT -f -j DROP
# Drop XMAS packets
-A INPUT -p tcp --tcp-flags ALL ALL -j DROP
# Drop NULL packets
-A INPUT -p tcp --tcp-flags ALL NONE -j DROP
# Accept all established inbound connections
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow all outbound traffic - you can modify this to only allow certain traffic
-A OUTPUT -j ACCEPT
# Allow HTTP and HTTPS connections from anywhere (the normal ports for websites and SSL).
-A INPUT -p tcp --dport 80 -j ACCEPT
-A INPUT -p tcp --dport 443 -j ACCEPT
# Allow email (postfix, dovecot)
-A INPUT -p tcp --dport 465 -j ACCEPT
-A INPUT -p tcp --dport 25 -j ACCEPT
-A INPUT -p tcp --dport 587 -j ACCEPT
-A INPUT -p tcp --dport 993 -j ACCEPT
# Allow SSH connections
# The -dport number should be the same port number you set in sshd_config
-A INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT
# Drop ping
-A INPUT -p icmp -m icmp --icmp-type 8 -j DROP
# Log iptables denied calls
-A INPUT -j LOG --log-prefix "iptables denied: " --log-level 7
# Reject all other inbound - default deny unless explicitly allowed policy
-A INPUT -j REJECT -A FORWARD -j REJECT COMMIT