We want to connect 2 physical networks to each other by a Mandrake 10.2 with 2 networkcards. Both are on the same subnet (10.0.0.0/24). The dhcp-request from physical network A may not go to physical network B and vice versa since each physical network has his own dhcp-server. When a computer in physical network A requests an ip-adres only the dhcp-server in physical network A may answer (whith it's perticular settings).

How can i set up the 2 network-cards so that all the traffic on nic1 is sent to nic2 and vice versa? The default gateway is always the same for all nics.

When the network card are set up, i can configure my firewall to block dhcp traffic from one physical network to the other.

Any suggestions?

Thanx in advance!

If you have two networks, you should be using two separate subnets. Otherwise, you could simply use a switch, unless you want to use the Mandrake host as a bridge.

Normally, the network address determines which interface traffic should be routed to.
You could google for "transparent bridge filtering" if that is what you have in mind.

It is not just a bridge. It has to block all dchp-request from one networkpart A to networkpart B and from networkpart B to networkpart A. Both networkparts are one the same subnet and have there own dhcp-server (each whith it's own non-overlapping ip-range).

A transparent bridge can be setup to block the DHCP traffic from passing. google for 'transparent filtering bridge'.

I don't understand why you don't just have one network and use one of the DHCP servers or have the two networks on different subnets. This is forcing you to use an exotic solution, violating the KISS rule.

jschiwal thanks for your advice. The reason for the weird configuration is that the network is actually consists of 2 networks (from each school) joined together. Connected to each other with a wireless bridge. We want the ip adresses from school A to be in a range 10.2.0.1-10.2.255.254 and for school B f.i. in 10.3.0.1-10.3.255.254. If there is only one dhcp server we can't set/predict what ip-adress the nic would get. We tried to use dhcp user classes but we don't get it to work.
I we can use 2 dhcp-server one in school A and one in school B and if we can prevent dhcp request to cross the bridge we get an ipadress in the right ip-range.

Hopefully my explanition is clear.

Should i use another configuration? Or just let them mangle the ipadresses?