Forcing LAN output to a specific interface?

[walker2]

I have an application that receives data from an outside LAN. All data going out from that application (only one to run on that machine!) is to be transmitted on our internal LAN.
All machines in the setup run XP. A spare do run Win 7, however.
(Both LANs are with only a few machines and no internet)

The external LAN runs with dynamic IPs the internal with fixed.

Currently the external data is received OK, but the outgoing data goes out on the same LAN!

WireShark can see both interfaces, and data coming in on both. I.e. the interfaces work.

I have found the Route Add command, which may solve this, but how?

The fixed IP will be something like 192.0.5.20.
Outgoing data is to be received on two different PCs! (different data sets)
My application works, if it is run on one of the internal PCs and the external LAN is connected to our switch directly.

Would something like the command below do the trick?

route add 0.0.0.0 mask 0.0.0.0 192.0.5.20

Or would I loose my incoming connection in the process?
Or something else?

 

[xwb]

Have you tried this

1) Open up the local area connection properties
2) Click on TCP/IP properties
3) There are 2 tabs - general and alternate configuration
4) Click on alternate configuration - most of the controls will be disabled if General is on DHCP. In your case it sounds like you are not on DHCP. You can add your 192 address in the alternate configuration. The card will then have 2 addresses on completely separate networks.