I have two NICs in my Exchange 2000 Server machine. I've configured two SMTP virtual servers so that each virtual server is bound to one of the NICs. Thus, I can route all outbound SMTP mail through one of the NICs. However, this configuration isn't working properly. How do I fix it?

This problem might be caused by faulty TCP/IP routing or by Exchange. Make sure that you've specified the correct default gateway on both NICs and set your internal NIC to use the external unit as a gateway. On the Exchange side, your best bet is to configure one SMTP virtual server to use the other server as a smart host. This configuration will force the smart host to route all mail through the other SMTP instance, which is probably what you want.