Mine

#!/bin/bash

# No spoofing
if [ -e /proc/sys/net/ipv4/conf/all/rp_filter ]
then
for filtre in /proc/sys/net/ipv4/conf/*/rp_filter
do
echo 1 > $filtre
done
fi 

# No icmp
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
echo 1 > /proc/sys/net/ipv4/ip_forward
#load some modules you may need
modprobe ip_tables
modprobe ip_nat_ftp
modprobe ip_nat_irc
modprobe iptable_filter
modprobe iptable_nat 
modprobe ip_conntrack_irc
modprobe ip_conntrack_ftp

# Remove all rules and chains
iptables -F
iptables -X

# first set the default behaviour => accept connections
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

# Create 2 chains, it allows to write a clean script
iptables -N FIREWALL
iptables -N TRUSTED

# Allow ESTABLISHED and RELATED incoming connection
iptables -A FIREWALL -i eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow loopback traffic
iptables -A FIREWALL -i lo -j ACCEPT
# Send all package to the TRUSTED chain
iptables -A FIREWALL -j TRUSTED
# DROP all other packets
iptables -A FIREWALL -j DROP

# Send all INPUT packets to the FIREWALL chain
iptables -A INPUT -j FIREWALL

#openvpn
iptables -A INPUT -i tun+ -j ACCEPT
iptables -A INPUT -i TAP+ -j ACCEPT
iptables -A FORWARD -i TAP+ -j FORWARD
iptables -A FORWARD -i tun+ -j FORWARD
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
iptables -A INPUT -i tun+ -j ACCEPT


# Allow https
iptables -A TRUSTED -i eth0 -p udp -m udp --dport 443 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 443 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 8080 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 22 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 8081 -j ACCEPT


#ftp
iptables -A TRUSTED -i eth0 -p udp -m udp --dport 21 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 21 -j ACCEPT

#vpn
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 1194 -j ACCEPT

# Allow IRC IDENT & DCC
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 6667 -j ACCEPT
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 113 -j ACCEPT

# Allow bittorrent
iptables -A TRUSTED -i eth0 -p tcp -m tcp --dport 6881:6889 -j ACCEPT

#allow samba
iptables -A INPUT -p udp -m udp --dport 137 -j ACCEPT
iptables -A INPUT -p udp -m udp --dport 138 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 139 -j ACCEPT

# End message
echo " [End iptables rules setting]"