Ok this may be a tough one since I'm flying a bit blind here - let me explain. We have a small domain made up of about 8 servers, two of which are Domain controllers. The original domain controller is a W2K server, a the second domain controller W2K3. We are running W2K Native mode active directory. The first DC has the PDC emulator role, while the second DC is master of the other operations. The second DC also handles DNS. Although the error occurred a bit before my joining the company (so long ago thatall error logs associated with the problem are gone), my supervisor is concerned that our servers aren't failing over properly, due to a supposed problem he had a few months back, when he rebooted a number of servers. He left the original (W2K) DC running, and rebooted our second DC, and also our IAS server, which also handles DHCP. Our IAS server came up before the second DC, but even when the second DC came up, no clients were able to retrieve DHCP addresses. My theory is that the DHCP was not able to check authorization in AD, but I can't be sure without the error logs to check, and we're not prepared to start shutting down servers in hopes of replicating the issue. Any ideas what the problem could be? Is there any information I haven't yet given that could help?

This has nothing to do with Windows Server Longhorn so if you have futher questions I suggest visiting one of the non-beta forums. But some general information about DHCP in AD: When the DHCP service starts I'm 95% sure it contacts a DC (any DC) to see if it is authorized. If it cant contact a DC it doesnt give out addresses... This would lead me to believe that you have other directory connectivity issues (that are probably not isolated to DHCP, but may be limited to the ISA server). Troubleshoot this as you would any issue where machines cannot contact a DC; start by troubleshooting DNS, routing/firewalling, etc. Cheers, Erik

somewhat helpful, but couldn't find any of the non-beta forums. had a hard enough time finding this one.