Client to Client Port Requirement RRS feed

  • Question

  • All,

    I am trying to figure out the FW Port requirements for Basic Lync IM\chat functionality between Client Segments. Not from Client to Lync Servers. 

    Came across the below article


    Based on the above, it seems, IM|Chat will work, without Clients Segments connectivity to each other on a specific Ports. As long as Client have all necessary ports opened to Lync Servers, IM will work.

    Can someone confirm this.


    Friday, June 9, 2017 6:06 AM

All replies

  • Hi Ashele,

    Lync send SIP messages over TCP and under normal circumstances, secures them with transport layer security (TLS). This protocol has to be Client-Server communication.

    All the ports the Lync client uses can be found below under Required Client Ports


    You may refer to below link as well for the protocol workflow.




    Friday, June 9, 2017 7:12 AM
  • Lync IM is never peer-to-peer because of possible Archiving requirements. So your connection is established to the pool, and so is true for the other party.

    When audio/video/app-sharing is involved, peer-to-peer connection is preferred to reduce quality issues

    Saturday, June 10, 2017 4:52 AM
  • Hi Ashele,

    Agree with others.

    As a supplement, for IM function, there is no specific Port required to be open on client end per your requirement, so long as Lync client have all necessary ports opened to Lync server, it will work fine.

    You simply need to use your username password for Lync and connect and the background it would connect to Autodiscover Setting on your server and pick it up. Below article should explain this part.

    Hope this reply is helpful to you.


    Alice Wang

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    • Proposed as answer by Alice-Wang Monday, June 12, 2017 9:01 AM
    Monday, June 12, 2017 2:01 AM