I have read a few posts about SBS dhcp shutting down. I don’t know if it is just SBS or not but I do know that SBS will shut down it’s dhcp service if it sees another dhcp server. I usually do two nic servers with the isp connected to the second nic. I do not recall ever seeing the dhcp server shut down with this config. I did see dhcp shut down at one account. Troubleshooting 101. Turn off all the workstations. It still shut down. Unplug everything from the switch except the sever. I started the dhcp and it stayed running. I start plugging in things and I see the service shut down. Curse the cable person who did not leave a drawing with cable jacks. Double curse the cable tech who comes back after I spent an hour making a drawing and he takes my drawing. Stupid me for not making copies, pdfs and stapling it to the wall. Back to the story. A cheap print sharing device has a dhcp service built in to it. Why? Who knows. I disabled it and all was well. Except the stupid thing reenabled itself. Toss that device out the window.
So I see people post in the SBS newsgroup about this dhcp issue. Someone said unbind the dhcp from the external nic. Sounds easy enough. I keep that thought in mind for later use. Finally I see someone post and I respond with my ISP to external nic, internal to network switch. He unplugged all the devices from the switch except the SBS. He still has the same problem. So I mention the unbind dhcp from the external nic. He posts back “How do you do that?” Fair question so I try it myself. Darned it I see it so I keep looking.
Go to your DHCP manager. Right click on your server name/properties/advanced/bindings. Make sure your only your internal
nic is checked.Try to restart dhcp after you unbind from external nic.