Inter Vlan Lync clients desktop sharing issue


  • My Lync clients are on different Vlans ,they can use messaging without issue .If they share their desktop with user in different vlan they get a network error and session fails.

    I thought Intervlan desktop sharing between peer-peer connection failed due to port restrictions invloved as communication between two internal users is one to one and would not invlove Lync server in between to which access is open from all the vlans.

    Now If these two users shares an application or presentation it works and immediatley after if they starts sharing the desktop , that works. But this stays good for that particular session only between them. If he signs out and reconnects again, he is not able to share desktop unless he starts over by sharing presentation or appliation first.

    I am trying to understand if desktop sharing session somehow establishes what restricts it initially. What ports between vlans should be considered if at all this could be due to this. Please suggest.

    Friday, July 22, 2011 7:21 AM

All replies

  • Hi,

    As its working intermittently that points to port issue. Please make sure you have the following port range open


    1024-65535 *


    Application sharing.


    Front End Servers

    Lync Server Application Sharing service



    Used for incoming SIP listening requests for application sharing.

    Front End Servers

    Lync Server Application Sharing service



    Media port range used for application sharing.

    Navin Microsoft Unified Communications
    Friday, July 22, 2011 12:35 PM
  • Thanks Navin, The port range is too wide to open. The application/presentation/whiteboard sharing is working in the present situation every time without adjusting ports. Only if we initiate desktop sharing first in the order it stucks .But If we share an application first and then start desktop sharing, It works.

    Monitoring Port activity shows that when the initial connection is sought it goes to the other party's IP and fails as the ports are restricted.Moment we share a poll/whiteboard,it goes to the server-establishes the connection and any subsequent connection thereafter (desktop share) use the established connection with the server and things work.

    I'll further test and share.


    Friday, July 22, 2011 2:59 PM
  • Did you limit the port ranges used for these media? Please see the configuring port ranges topics in the QoS section of the documentation library how to do this on server and clients. It might help you to open up some ports between VLANs
    Technical Specialist Microsoft OCS/Lync & UC Voice Specialisation -
    If you think my post is the answer to your question, please mark it as answer so future visitors can easily find it.
    Friday, July 22, 2011 6:43 PM
  • Do you configurate the vlans in one switch or multiple swiches?

    If you desktop sharing can work successfully in the same vlan and failed in the different vlans, maybe something wrong with the vlan configuration.

    Please check your configuration in the switches and verify you have open all the ports between VLANS.

    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
    Wednesday, July 27, 2011 8:57 AM
  • Any update?
    Navin Microsoft Unified Communications
    Thursday, August 04, 2011 10:39 AM
  • Hi Shireesh,

    Were you able to resolve this issue? I am having exact same issue with my Lync environment. 

    • Edited by zali Monday, April 30, 2012 5:22 PM
    Monday, April 30, 2012 5:20 PM
  • This you can achieve by opening media port ranges between the clients.Means when you share deskop(peer to peer)communication happening between 2 clients.So both client should have access to media port ranges each other.These media port ranges you can limit using powershell.For dektop sharing i think only 40 ports are enough.

    Jayakumar K

    Friday, June 22, 2012 3:43 PM
  • I am facing different issue where I am able to share desktop but during Audio Video call i am getting network error. I have opned all the port to server from all the LAN. Within same VLAN its happening happening but in inter VLAN its failed. Any suggestion?
    Friday, July 13, 2012 12:00 PM
  • So you still have firewall/port problems.

    Use the Lync workloadposter

    and use the firewall rules viewer

    regards Holger Technical Specialist UC

    Friday, July 13, 2012 2:32 PM