I have set up our DC as a RAS server.
I am now aware that this it not a recommended thing to do, but it's done, and it's our only server so it saves me a lot of work if I can keep it like this.
It's been working fine until I tried to install a new application, a backup agent.
It's supposed to communicate on port 8006, and it does, but from the "PPP RAS Dial in interface" and not from "Ethernet Adapter"

I have these two adapters present:

PPP adapter RAS (Dial In) Interface: (only present after I have connected once with VPN)
   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 10.21.31.117
   Subnet Mask . . . . . . . . . . . : 255.255.255.255
   Default Gateway . . . . . . . . . :

Ethernet adapter Ethernet:
   Connection-specific DNS Suffix  . :
    IPv4 Address. . . . . . . . . . . : 10.21.31.3
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 10.21.31.1

Telnet port 8006 from another host in the network connects only to 10.21.31.117, not to 10.21.31.3
Telnet port 8006 on the server itself connects to 10.21.31.117, localhost and 127.0.0.1, but not to 10.21.31.3
Telnet to other services from another host connects to both adapters, services that has been installed prior to RAS.
Ping from other hosts goes fine to both addresses.

 Netstat tells me all adapters are listening on 8006
TCP    0.0.0.0:8006           MTT-DC1:0              LISTENING

Anybody who knows how I can connect to the correct adapter?

• Edited by tortoret 22 hours 46 minutes ago

  Indeed you should never set up a DC as a remote access server, and the reason is the one you discovered. As soon as you connect a remote user, the DC is multihomed and you never know what IP the server name will resolve to. It is a long-standing problem and the best solution is to avoid it in the first place.

  If you want to try to work around it, have a look at KB292822.

Thanks, I'll have a look at the KB and see if I'll go for the workaround.
But then a follow up question: May the same problems appear on other servers, or is this unique for DC/DNS servers?

  It will always happen. It causes more problems on DCs.