port forwarding with one interface to trace traffic?

[Rasca <rasca-ml@triad.de>]

Hi IP-gurus,

I want to setup a specific port forwarding to trace the
ip traffic between a macos9 and a hp net printer to debug
a spooler problem.

I thought the port forwarding feature of linux/iptables
would be nice to do that. But until now I wasn't able
to get it running ;-(

May be some one can help here. The setup is quite simple.

* one class C net (192.168.10.0)
* a linux box with one interface (eth0), kernel 2.4.24
   and iptables 1.2.9 (192.168.10.156

* macos9 machine with 9.2.x (192.168.10...)

* HP laser printer with network interface (192.168.10.9)

I want to configure the Mac to print to the linux box.
The linux box should do port forwarding to the hp printer.
So I can use "ethereal" or what ever to dump the traffic.

Because it's not a firewall all chains have as default
"accept".

I added the following rule (which seems not to be enough,
cause the printing freezes):

iptables -t nat -A PREROUTING -p tcp --dport 515 \
	-d 192.168.10.156/32 -j DNAT --to-dest 192.168.10.9:515

Any ideas?

thx + cu
  rasca


-- 
_______________________________________________________________
| Triad Berlin Projektgesellschaft mbH | http://www.triad.de/ |