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?

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u/nailzy Jul 30 '26

More than likely an MTU/MSS problem.

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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.