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RDPEFS messages not received RRS feed

  • Question

  • Hi everybody,

     my Java based RDP client implements RDPEFS (RDP 5 based) since many years ago and with Windows Server 2008 R2 and previous it works fine, but recently I tested it with Windows Server 2012 and Windows Server 2016 and it doesn't work anymore.

    Has it been any important change in the protocol?

    In the following link you can see a trace captured with Microsoft Message Analyzer:

      https://drive.google.com/file/d/1F5_Nua2jkbafHxbb0JyXLVFrinDtbm0_/view?usp=sharing

    In the trace you will see the messages to open the "rdpdr", "clipdr" and "drdynvc" channels (Client MSC Connect Initial PDU), the server response with the channel numbers, the "Channel Join Request PDU" for every channel with the response. But the server does not send any "Server Announce Request" message in the "rdpdr" channel to initiate the communication.

    What am I missing?

    Thank you!

    Monday, June 8, 2020 7:20 AM

Answers

  • Hi Bstia,

    Please make sure you are opening the rdpsnd static virtual channel, as [MS-RDPEFS] depends on it:

    [MS-RDPEFS]

    2.1 Transport

    This protocol runs over a static virtual channel with the null-terminated ANSI encoded name "RDPDR".<1> Static virtual channels are defined in [MS-RDPBCGR] section 3.1.5.2.

    <1> Section 2.1: In Windows (unsupported in Windows 2000 operating system, Windows XP and Windows Server 2003), the client advertises the static virtual channel named "RDPSND", as defined in [MS-RDPEA]. If that channel is not advertised, the server will not issue any communication on the "RDPDR" channel.

    I hope that helps!


    Jeff McCashland | Microsoft Protocols Open Specifications Team

    Wednesday, June 17, 2020 5:06 PM
    Moderator

All replies

  • Hi Bstia

    Thanks for the question about Open Specifications.

    One of the Open Specifications Engineer will respond shortly to assist you.



    HungChun Yu (MSFT)


    Monday, June 8, 2020 4:42 PM
  • Hi Bstia,

    I will need to collect new net traces with a concurrent TTT trace of lsass. Please email me at our alias DocHelp @microsoft .com, so I can provide you with information to download the necessary tools and upload the new traces. 

    Thanks,


    Jeff McCashland | Microsoft Protocols Open Specifications Team

    Monday, June 8, 2020 5:37 PM
    Moderator
  • Hi Bstia,

    Please make sure you are opening the rdpsnd static virtual channel, as [MS-RDPEFS] depends on it:

    [MS-RDPEFS]

    2.1 Transport

    This protocol runs over a static virtual channel with the null-terminated ANSI encoded name "RDPDR".<1> Static virtual channels are defined in [MS-RDPBCGR] section 3.1.5.2.

    <1> Section 2.1: In Windows (unsupported in Windows 2000 operating system, Windows XP and Windows Server 2003), the client advertises the static virtual channel named "RDPSND", as defined in [MS-RDPEA]. If that channel is not advertised, the server will not issue any communication on the "RDPDR" channel.

    I hope that helps!


    Jeff McCashland | Microsoft Protocols Open Specifications Team

    Wednesday, June 17, 2020 5:06 PM
    Moderator