Arch :: rc.firewall v2

#!/bin/sh

firewall_start() {
iptables -F
iptables -t nat -F
iptables -t mangle -F

# Setting default policies
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
iptables -P FORWARD DROP

# Basic Firewall
iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

# Allow SSH
iptables -A INPUT -i eth+ -p tcp -m tcp --dport 22 -j ACCEPT

# (link 3) throw everything else away
iptables -A INPUT -j DROP

# Allow myself to be a non-passive FTP client
iptables -A INPUT -p tcp --dport ftp-data --jump ACCEPT

# No Telnet!
iptables -A OUTPUT -p tcp --dport telnet --jump REJECT

# Otherwise, drop inbound TCP packets with ICMP messages
iptables -A INPUT -p tcp --jump REJECT
iptables -A INPUT -p udp --jump REJECT

# Report what happened
echo 'Firewall rules installed:'
iptables -L

}


> then run

/etc/rc.d/rc.firewall >> /etc/rc.local