I have had this problem before. The gateway reverting to blank indicates a conflict. If you go to the properties of the network adapter; you have a static IP set with DNS and DHCP pointing to the server IP itself, right?? In addition, The interfaces tab of dns should have the static IP of the NIC checked. Uncheck any other addresses that may conflict. start;>administative tools->dns - then right click the server name and go to properties -> interfaces tab. That said and correct , run the wizzard and you should not have the gateway falling out.... Unless your router configuration is wrong. Your router should not be doing DHCP and the server should have root hints populeted in the DNS properties... You can add the DNS entries the forwarders tab.... That is not recommended any more, however, that may be a work around,,,,, And last but not least.... go to SBS console-> Network -> connectivity tab... Now look to the right... Run the Fix my Network wizzard and then the connect to internet wizzard and see if that does not fix this issue.
I hope this helps,
Louis
