SIP trunk drops inbound calls after 10 sec

Discussion in 'General' started by JPP1962, Nov 18, 2009.

  1. JPP1962

    Jan 17, 2009
    Likes Received:

    I just setup a sip trunk to a provider and I can make calls without problem. I receive calls but they look like in "demo mode" after 10 seconds the call is dropped.

    I have searched and searched and couldn't find out why. I think it must have something to do with NAT (firewall ports are open and I have no sound problems)

    here is a simple diagram of my network

    I also did a sip debug on my Elastix box but (I'm no Asterisk guru :( ) but couldn't understand it. I see the INVITE from the provider, but I can't figure out the reason why there is no answer.

    My setup: Elastix 1.6; Zoiper soft phone and Siemens Gigaset A580IP.
    extern_ip =
    localnet =

    Attached is an output of my CLI where there is the SIP trunk config and the SIP debug of an incoming call.

    Any ideas where to look, what to ask to the provider are more highly appreciated.

  2. rphenix

    Feb 25, 2009
    Likes Received:
    Have you tried working out the IP(s) from the provider and temporarily forwarding all traffic to your PBX (i.e. unblock everything).

    Also its been my experience to leave sip_nat.conf blank.

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