> Hello all: > > I am having trouble getting port forwarding > with iptables to work. > > I have this configuration: > > Internet --- Linux machine --- Windows machine > > The windows machine is set up to listen on > IP address 10.0.0.31 > > I am able to use lynx to connect to http://10.0.0.31 on > the linux machine so there is no problem going from > the linux machine to the windows machine. > > I have tied a public IP address a.b.c.d to the > linux machine and entered these rules in its > firewall: > > /sbin/ifconfig eth0:1 $WIN_EXTERNAL_IP netmask $ETH0_NETMASK broadcast > $ETH0_BCAST > /sbin/iptables -t nat -A PREROUTING -p tcp -i eth0 -d $WIN_EXTERNAL_IP > --dport 80 -j DNAT --to $WIN_INTERNAL_IP:80 > /sbin/iptables -A FORWARD -p tcp -i eth0 -d $WIN_INTERNAL_IP --dport 80 -j > ACCEPT > > I have this log entry at the bottom of the firewall rules: > > /sbin/iptables -A FORWARD -j LOG --log-prefix "FORWARD " > > When I try to go to the external IP address http://a.b.c.d from > another network, I get an error. Do you have return POSTROUTING rules in your iptables nat table, have you enabled ip forwarding?