While I was pinging my Windows Server 2008 r2 server domain controller (out of sheer boredom) by its hostname ("dc.contoso.com"), I noticed that instead of getting the expected IP address 192.168.0.1, I got IP address 192.168.0.27. I remote accessed that IP address, and it was indeed that same domain controller.
To the best of my knowledge, I had never assigned address 192.168.0.27 to any host. I looked at the NIC definition for the domain controller, and indeed, only 192.168.0.1 was defined.
So I looked at my DNS (on the same domain controller), and saw that there were two A records for "DC" - one for 192.168.0.1 (as expected), and another A record for "DC" pointing to 192.168.0.27. I had never, ever, created that A record.
I was confused. I took a look at my DHCP records, and found 10 inexplicable reservation entries, including 192.168.0.27 - all created by "RAS". This reminded me that on the day I did the ping, I had accessed my network via RRAS VPN (RRAS role also on same domain controller) for the first time in a very long while. I did some reading, which explained that RRAS creates 10 DHCP records. I use VPN so very rarely that I may just never have noticed this before.
My question is: I understand now why I have the 10 DHCP entries, but why the superfluous DNS entry for dc.contoso.com with the alternate IP address? I expect that when I ping dc.contoso.com I will get the IP address I assigned to it! Is this some misconfiguration by me, a known bug, or expected behavior? Does it matter?
TIA,
mlavie