This one's driving me crazy. Here's my situation:
I've got a single Exchange 2003 Enterprise Edition SP2 Back-end server and 2 Exchange 2003 Enterprise Edition SP2 Front-end servers. None of the Exchange servers are Domain Controllers. I have 3 separate Windows 2003 SP1 Standard Edition Domain controllers, and a single Windows 2000 DC. 2 of the 2003 DC's are Global Catalog servers, as well as the 2000 DC. All 3 Exchange servers have been configured correctly in Exchange System Manager for RPC over HTTP. The two front end servers have been configured identically, yet RPC/HTTP only works on one of them. I've checked and re-checked the appropriate registry entries, certificates and have uninstalled/reinstalled RPC/HTTP on the box that doesn't work to no avail. Both of the front-end servers have the exact same ValidPorts value in the HKLM\Software\Microsoft\Rpc\RpcProxy key. IIS is configured identically on both front end boxes.
Am I missing something somewhere? Is there a limitation with RPC/HTTP that only allows one front-end server?
Any help will be greatly appreciated!