TCP or UDP 3389? RRS feed

  • Question

  • Hi there,

    I have a question about which port is being used in the Remore Desktop service. I have a Windows server 2008 R2 server with RD service running. I would like to know that is the RD service use the TCP 3389 or UDP 3389 for the RDP session? I heard that the TCP 3389 is being used during the user authenication and then once it is authenicated the session will be switched to UDP 3389. Is it correct? If this is correct is there anyway i can force the RD session to use TCP port 3389 only (e.g. by changing the registry settings)? Please advise.


    Tuesday, April 26, 2011 9:51 AM


All replies

  • RDP uses TCP 3389 only


    This forum post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.

    Tuesday, April 26, 2011 10:25 AM
  • Thanks for the answer.

    I forgot to mention that I am using 'Remote App' on my Windows 2008 R2 server with Digital signature enabled. In this case I want to know is the RDP seesion use TCP 3389 or it would use TCP 443?

    Many thanks,

    Wednesday, April 27, 2011 2:28 AM
  • You'll still be using TCP 3389. You can confirm this by using TCPView on both the client and server while making a connection:

    RD Gateway, for remote access, uses TCP 443, but only between the client and the RD Gateway box. TCP 3389 is then used between RD Gateway and the RDS server. See more on RD Gateway network requirements here:

    This forum post is my own opinion and does not necessarily reflect the opinion or view of Microsoft, its employees, or other MVPs.
    Wednesday, April 27, 2011 7:14 AM
  • Just a little observation I made today, when I was remoting into my server (using mstsc, from windows 8.1), connection was slow, and it said that it was using UDP instead ... So ... Im guessing that RDP can use UDP now? ... Is kind of annoying, because I havn't set up UDP port forwards Lol, so it just disconnects me when it tries to switch over Lol ... Gunna change that now though :D
    Tuesday, October 22, 2013 5:40 PM
  • Hi,

    RDP 8.0/8.1 can use TCP only, or TCP and UDP.  You should not be seeing disconnects as a result of UDP being blocked by your firewall.  The RD Client should detect that UDP is not available and only use TCP.


    Tuesday, October 22, 2013 5:45 PM
  • We are experiencing disconnects now when connecting to Windows Server 2012 computers. But I haven't heard from users (yet) and we have a few "loud" ones who are using this server.. ;)

    Best regards,
    Thomas Paulsen
    Senior consultant, MCITP: EA & SP2010, MCT
    iTet as
    Nordland, Norway

    Tuesday, November 12, 2013 12:56 PM
  • if you upgrade your RDS infrastructure to 2012 or 2012 R2 and have the latest RDP client installed, you can leverage both TCP and UDP for best results.

    if you're on 2008 then TCP is the only protocol which can be used, regardless of the client version.

    Tuesday, November 12, 2013 2:22 PM