Smilin{/b] is right ...most of the time in this case.
We use "multi-homed" servers in all of our LAN centers, for backups.
Primary nic, with DNS record: Windows/LAN/client traffic. (Static IP)
Secondary nic, with NO DNS record, on a different (private) subnet, dedicated to backup traffic only.
Default gateway is only configured on the Primary nic, and DNS servers also configured only on primary nic. (misleading info from ipconfig /all...DNS is set for the IP stack, not per nic) No WINS servers configured for the secondary nic either.
IP routing is disabled (of course)
HTH,