iptables portforwarding, how?

[dev-null-devil]

How do i portforward all incoming packets on my router (eth0) to an internal machine, the internal machine is a virtual server connected through a tap0 device, so i need something like this (in human language):

all connections to my server on port 80, should be forwarded to 192.x.x.x on tap0 from eth0. (eth0 contains the external ip.)

Sorry, but thats just the best i could do, im not really familiar with iptables or the linux (/unix) language.. yet.
Hope someone could clear this up anyway.

/Peter
_________________
All change, motion, and time is an illusion.
-- Plato, year 310

[cvk]

If I remember correctly

[dev-null-devil]

My eth1 device has 192.168.x.x and that is the same number as on my tap0 device, so i need to specify the tap0 device somehow.
// Friend told me so, but he cant configure iptables
_________________
All change, motion, and time is an illusion.
-- Plato, year 310

[cvk]

You can add the "-o" parameter to specify the out-interface.

chris
_________________
Adopt an unanswered post now.

[dev-null-devil]

Like this (just add?):
iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth0 -o tap0 -j DNAT --to 192.x.x.x:80

or this (replace?):
iptables -t nat -A PREROUTING -p tcp --dport 80 -o tap0 -j DNAT --to 192.x.x.x:80

mumble mumble, sorry for my newbiness, is there btw, somewhere i can read about iptables, or offcourse i mean learn?
_________________
All change, motion, and time is an illusion.
-- Plato, year 310

[sschlueter]