Masquerading Made Simple HOWTO

$> modprobe ipt_MASQUERADE # If this fails, try continuing anyway



$> iptables -F; iptables -t nat -F; iptables -t mangle -F



$> iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to 123.12.23.43



$> echo 1 > /proc/sys/net/ipv4/ip_forward



Then to secure it:







$> iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT



$> iptables -A INPUT -m state --state NEW -i ! eth0 -j ACCEPT



$> iptables -P INPUT DROP #only if the first two are succesful



$> iptables -A FORWARD -i eth0 -o eth0 -j REJECT



Or for a dial-up connection (with eth0 as the internal network card):



$> iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT



$> iptables -A INPUT -m state --state NEW -i ! ppp0 -j ACCEPT



$> iptables -P INPUT DROP #only if the first two are succesful



$> iptables -A FORWARD -i ppp0 -o ppp0 -j REJECT















$> iptables -F; iptables -t nat -F; iptables -t mangle -F