On prem Domain Controller responding on 2 names

[Boe Dillard]

I've inherited a network with 2 domain controllers in 2 different locations.   If we make a change on either dc the items are updated on the other.

However, if we take down the VPN between the two offices – remote office AD won’t open.

I see 3 DCs in ADUC however there are only 2.   When I ping the 3rd one the primary DC responds – so it is responding to both.  

The server name in the computer properties is Host1 but I can also ping it by DC1.  The other DC – Remote1 only replies to Remote1.

Any thoughts on where I should start?

[#2]

Sounds like DNS, if there is a DNS service running on both Domain Controllers and what do the clients receive as a DNS server? And do you have a CNAME object for that IP/name?

[#3]

Did you manage to fix the issue?

[#4]

Thanks - not yet. I've scoured the DNS but no luck.

[#5]

"However, if we take down the VPN between the two offices – remote office AD won’t open." Could you explain the behavior a bit more? People in the remote office can't log in anymore or?