File Transfer issue RRS feed

  • Question

  • Hi guys,


    I've deployed OCS + OCS edge server. The edge server resides within a DMZ and has 2 ethernet interfaces.

    The edge server's interfaces are connected to ISA 2006.

    Connecting with the communicator from the internet isn't a problem, IM isn't a problem either.

    The thing is that when transferring a file to another communicator user, the file gets blocked within ISA.

    BUT...... sending a file from a communicator residing on the internet to a communicator residing within the LAN does work!


    I've looked at the ISA monitoring and it looks like the OCS server residing in the LAN that it will transfer the file over port 6891 to The thing is that we're not using 10.x.x.x addresses. There is nothing in the ocs documentation that refers to port 6891.


    Is there anyone that has a solution to my problem?


    Regards, Mark

    Monday, September 3, 2007 7:05 PM


All replies


    For reference, there is another thread on the same topic at http://forums.microsoft.com/OCS2007/ShowPost.aspx?PostID=2030427&SiteID=57.


    The bottom line is that file transfer is peer to peer, so you'd have to allow TCP 6891-6900 from to/from everywhere for file transfer to work.

    Monday, September 3, 2007 9:41 PM
  • Hi Mike,


    I was able to change the rule i made in ISA 2006 into a working rule.

    I'm able to send files from external to internal and backwards.


    I still have a problem when 2 users are external and want to transfer files.

    At this moment file transfer between 2 external users isn't possible.


    How does file transfer work between 2 external users?

    Is the file first being transferred to the edge server and then to the other user?


    Regards, Mark


    Thursday, September 6, 2007 1:35 PM
  • No, files are transferred directly between the 2 users (peer to peer), so there's no way to ensure that this will work.  You'll probably find from time to time that even file transfers between an outside and inside user fail for the same reason.
    Thursday, September 6, 2007 2:30 PM
  • Hello,

    so file transfer is done peer to peer at the moment. What about when there will be product available for virus protection for IM? Hopefully then we will have same behaiviour as in LCS, it forces file transfer through server. Or can this be forced in external user sending file to external user scenario? Perhaps not because in LCS it did not work if antivirus was installed on Access Proxy.


    We'll see whats happening.




    Wednesday, November 28, 2007 8:04 PM