Routing question

jeffvph · 11-07-2005, 12:32 AM

I have a RedHat 9 box with 2.4.20-8 kernel connected to the internet via wireless wlan0 (x.x.x.x IP). The box also has 2 LAN cards eth0 (y.y.y.y) and eth1 (z.z.z.z).

z.z.z.z/24 network has full access to the internet while y.y.y.y/24 is not exposed to the internet. I need 1 host from z.z.z.z/24 network (lets say z.z.z.20) connected to another host in y.y.y.y/24 (y.y.y.20) on port 1972 only using iptables.

I know this is possible but I just dont know how. I will very much appreciate your help.

Thanks

~=gr3p=~ · 11-07-2005, 05:34 AM

Run these commands:

# echo 1 > /proc/sys/net/ipv4/ip_forward
# iptables -A FORWARD -i eth1 -s z.z.z.20 -o eth0 -d y.y.y.20 -p tcp --dport 1972 -j ACCEPT

Noe check the rule:
# iptables -L -n FORWARD

save the rule

jeffvph · 11-07-2005, 07:14 PM

Thanks grep, the packet forwarded seems not coming back from y.y.y.20 so added this line and it worked.

iptables -A FORWARD -i eth0 -s y.y.y.20 -o eth1 -d z.z.z.20 -p tcp --dport 1972 -j ACCEPT

Again thank you very much for your help.