I have recently upgraded a clients 2003 SBS with another network card so that they can have one public and one private interface in order to use the built in SBS2003 VPN and Outlook Web Access facilities properly.
The SBS server runs DNS and WINS services for the local domain. On single NIC configuration with a local IP address and ADSL router all works well, however as soon as the second card (An Intel PRO1000 PCIe with the latest driver from installed) is enabled and the “Connect to the Internet” wizard run, the SBS can only very intermittently ping an address on the Internet.
Broadband is through ZEN (a UK ISP) with a subnet of 8 public addresses – I have correctly configured the WAN address and router – this I have tested by giving one of the domain machines a public address and this works faultlessly.
It seems that it is only the local server which has the packet loss problem – as when setup as a dual NIC configuration client machines can route through the SBS server. I have tried everything I can think of but have had no success in sorting this intermittent local routing issue.
Can anyone help?!
An idea – could router MTU be the problem?