I'm using Mandrake 8.2 with iptables and not those weird $IPTABLES thingy I've been seeing a lot of. Just what are they anyways?

My problem is that I want to forward port 6112 from the outside world to 192.168.1.3 (both are using eth0). What exactly do I need?

My current config consists of:

modprobe iptable_nat
echo 1 > /proc/sys/net/ipv4/ip_forward

#[Basic Routing]
/sbin/iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -j MASQUERADE

THAT'S IT!! It works for anything the windows client use, like ICQ, Web browsingm, etc. But if I were to foward a port 6112, I was told that I need DNAT for incomming and SNAT for outgoing. Also one more question: Can I forward 1 port over a range of internal IPs? Just what would happen if it does work? And is it possible for a packet that is forwarded to port 6112 be redirected to EITHER of the many windows client that is connected to the Linux box? (eg, 2 different windows clients uses port 6112 to contact with the outside world, any way to modify the incomming packets, headers, etc so it fowards to client 1 or client 2 accordingly?)

Thanks a bunch!!

iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 6112 -j DNAT --to 192.168.1.3

And do that for udp as well

You can only forward one port to one ip one time.
Oh and you do not need any snat rules.

Many users define /sbin/iptables as a variable in their firewall scripts soas not to keep typing /sbin. $IPTABLES and /sbin/iptables are thus the same thing provided the defintion exists.

Cheers!