I'm having an issue where I cannot connect to a DC (\\DC1.help.local) via name but can connect through IP.

What happened was our main DC (DC1 on network 172.16.1.1/24) went down due to motherboard failure. When DC1 was brought back online all users within its own network (172.16.1.1/24) could access it by name (DC1.help.local) but our external office networks (172.16.2.1 - 4.1/24) could not. When you try to visit \\dc1.help.local externally you get: Logon Failure: The target account name is incorrect.

On the forward lookup zones under _msdcs I can see all the proper Alias CNAME records, no duplicates. When you try to connect via this Alias CNAME of other DC's, you can, except for DC1's Alias CNAME. When you try, it pops this message up:

You were not connected because a duplicate name exists on the network.

I can assure you that we have not cloned DC1 nor have we brought anything online that resembles this. We also only have one nic card on DC1.

Any thoughts on how to correct this problem?

1. Clear cache ipconfig /flushdns and refresh.

2. Diagnose your system (AD, DNS) with dcdiag (or netdiag in olde systems)

Rgds

Milos