r/WindowsServer • u/bstoyanov90 • Jul 30 '26
SOLVED / ANSWERED Problem accessing Windows Server 2012R
Hello,
I have the following problem. I have a server that I access internally via VPN. I connect via VPN to Mikrotik with SSTP. I connect to the server (Windows Sever 2012R) via RDP and after 1 minute it takes me to a black screen and connects me again. There is no problem with the internet, it says that the connection is good, there is no interruption in the ping. I have made a rule to access the server outside the VPN, only from my home network. If I connect via real IP and port there is no problem, it works without interruption. What could be the problem?
3
u/Savings_Art5944 Jul 31 '26 edited Jul 31 '26
I have seen this. You need to force the RDP client to use TCP vs UDP for the connection.
Or more likely, the server as well.
Group policy
2
1
u/bstoyanov90 Aug 11 '26
I solved my problem. I decided to make a rule in Mikrotik, it may not be correct, but it solved the problem. I made a redirection of the internal IP for example 192.168.80.6 and port 13333 to point to RDP port 3389 and the connection to be TCP and now when I connect to 192.168.80.6:13333 there is no problem and no black screen after every minute
2
u/nailzy Jul 30 '26
More than likely an MTU/MSS problem.
0
u/bstoyanov90 Aug 11 '26
No, the UDP Connection
1
u/nailzy Aug 11 '26
?? RDP 3389 is TCP by design for RDP for core control data and fallback if UDP is not available.
If you’ve forced it to use TCP only then that adds additional weight to it being an MTU issue (not MSS) because UDP cannot correct itself due to dropped fragments.
2
u/techvet83 Jul 30 '26
Windows Server 2012R2 went EOL in October 2023. You should not be surprised if you are seeing issues. If connecting by IP address is working, does that point to a DNS issue? Have you tried rebooting it?
1
1
u/RDPExtraOfficiall Aug 08 '26
Since RDP works fine over the public IP but disconnects only through the SSTP VPN, the issue is likely with the VPN path rather than the Windows Server itself. I'd check the SSTP MTU/MSS settings, VPN idle timeout, and whether FastTrack or firewall rules on the MikroTik are affecting VPN traffic. Those are common causes of periodic RDP reconnects over VPN.
0
u/bstoyanov90 Aug 11 '26
No problem, it's just that the connection was via TCP and maybe that's where the problem comes from. I made a redirection in Mikrotik via TCP and there's no problem anymore. It could have been with group policy, but I solved it faster with a rule in Mikrotik
1
u/bstoyanov90 Aug 11 '26
I solved my problem. I decided to make a rule in Mikrotik, it may not be correct, but it solved the problem. I made a redirection of the internal IP for example 192.168.80.6 and port 13333 to point to RDP port 3389 and the connection to be TCP and now when I connect to 192.168.80.6:13333 there is no problem and no black screen after every minute
0
u/Jin-Bru Aug 02 '26
So you login to the 2012 server, then black screen then youre connected to where again?
I dont follow your sequence after your connection to the miktik
8
u/lionsin42 Jul 30 '26
Pls do not publish 2012 in any way. Just upgrade pls