Just a mental note.
sysctl -w net.ipv4.ip_forward=1 >> /etc/sysctl.conf
iptables -I POSTROUTING -t nat -o eth0 -j MASQUERADE
iptables -I FORWARD -i eth1 -o eth0 -m state --state NEW -j ACCEPT
iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
service iptables save
sysctl -w net.ipv4.ip_forward=1 >> /etc/sysctl.conf
iptables -I POSTROUTING -t nat -o eth0 -j MASQUERADE
iptables -I FORWARD -i eth1 -o eth0 -m state --state NEW -j ACCEPT
iptables -I FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT
service iptables save