Multiple Internet connections on 1 server

[Boondy]

Our company has a permanent dial up connection for our E-Mail (Exchange 2000) and a cable modem for our internet connection.

I am trying to migrate both services onto the one Exchange Server.

I have a Netgear Dialup Router and a Netgear Cable Modem Router which i intend to run through a watchguard firewall. The internet is currently shared out with ISA server.

I have installed 3 NIC's in the server, 1 for the LAN 1 for the Dialup Router and 1 for the Cable router. My intention is that once it is set up and working properly, i will remove the 3rd Nic from the server, and run both routers through the firewall and into the 2nd NIC on the server....

My problem is this.... I can't seem to have 2 simultaneous internet connections on the one server. When both the Cable and Dialup NIC's are connected it will either Receive/Send mail over the Dialup, but not access internet over the cable OR it will access the internet over the Cable modem and send email over the cable, but it will not receive mail over the dialup.

When connected to the firewall i can see the SMTP packets comming through the dialup destined for the Exchange server, but they never seem to reach the exchange server...

I first thought that i was creating a loop, so i set up packet filters on both routers, blocking SMTP on one and allowing it on the other, and same with HTTP....But this hasn't helped....

Am i trying to do something that cannot be done? Or have i forgotted a crutial step???

Anyone?

 

[dankelt]

Sounds like a routing problem to me. How are you routing traffic on that box? Are you using a routing protocol or just setting static routes?

Say for example you have both connections active, but have a default GW for out the cable modem. Then say SMTP traffic comes in the dialup, the server's replies will then go out the cable modem interface.


Dan

 

[Boondy]

So how can i get it to reply to SMTP on the dialup interface only?

 

[dankelt]

That's a good question, I've never done layer 4 routing on a windows box. Linux yes, windows???? Don't know. I will do a little research and let you know if I find anything.

Maybe someone else has a better idea on how you can accomplish this... Can't say I've ever done anything like this!

Dan