We have the following configuration :

A sbs-2003 server in a domain (mydomain.com) with 2 network cards, each connected to a different network (provider), with different gateways, one for web and one for mail and clients.

(we do this because the bandwitdh we get from our providers is too small to handle all the mail(+spam) traffic and webservices, so we took 2 providers)

DNS is as follows :

www.mydomain.com 1.2.3.4

mail.mydomain.com 5.6.7.8

NIC 1(192.168.1.3) is connected to to the internet through a firewall at 192.168.1.1, having wan address 1.2.3.4

NIC 2(10.0.0.3) is connected to to the internet through a firewall at 10.0.0.1, having wan address 5.6.7.8

Both nics have their default gateway installed at their corresponding routers. Also the metrics are set equal. (i know this isn't a supported config, but it works more or less). In this configuration i can use RDP on both wan adresses, and telnet to port 25 works as well on both.

The issue now is that since a few weeks , we get regular disconnections, and website hickups(timeouts), several per hour.

If we set one router to a higher metric, that route no longer works.

In short, I want the mails to route through NIC2 and the web through NIC1.

Any better configuration (without installing a second mail server) ?