Setting firewall di ubuntu server

1. nano /etc/rc.local
2. ketik
echo "1" > /proc/sys/net/ipv4/ip_forward

ipt=`which iptables`

$ipt -F -t nat
$ipt -X -t nat

$ipt -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 3128
$ipt -t nat -A PREROUTING -p udp --dport 53 -j REDIRECT --to-port 53
$ipt -t nat -A PREROUTING -p tcp --dport 53 -j REDIRECT --to-port 53

$ipt -t nat -A POSTROUTING -o eth0 -j MASQUERADE

exit 0
3. reboot