SIP/RTP Incoming calls only work for 30 seconds, then disconnect RRS feed

  • Question

  • I have a Windows 2008 R2 TMG server as the Edge Firewall. I have a 3CX PBX system internally.

    Before putting in TMG, I had a linksys BEFSX41 firewall/router. I did port forwarding on TCP 5050, 5060 and 5090, which is what 3CX required. I also was asked by my Provider, AITech, to port forward UDP ports 10000-50000. I did this, and the PBX worked fine.

    I then installed TMG as the edge firewall.

    I cannot receive incoming calls for longer than 30 seconds to the 3CX PBX I have. I used the 'Config VoIP access' tool for the firewall rules. It created 3 rules once done. I have tried various combinations of this rule and still had no luck persisting an inbound call past 30 seconds. I believe it is RTP related since the logs show the UDP ports are getting denied.

    I can make calls from inside the network outside, with no issues. So the problem is only related to inbound calls coming from the outside.

    Let me know if anyone has any ideas here.


    Friday, September 3, 2010 2:35 PM

All replies

  • Info needed:


    We need to know what options you chose when configuring the SIP filter


    We also need to know whether the Phones talk to Internal PBX and internal PBX talks to external PBX ?


    Do they have a direct phone line to their internal PBX?


    i.e we need their PBX , phone layout diagram and what options they chose for in the TMG SIP filter config

    Is it possibel to share this info?


    Bala Natarajan [MSFT]| Sr. Support Escalation Engineer | CSS Security
    Wednesday, September 29, 2010 7:08 PM
  • Do you have any furtrher updates?
    Bala Natarajan [MSFT]| Sr. Support Escalation Engineer | CSS Security
    Wednesday, October 20, 2010 4:10 PM