No media being sent in SIP call

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Asterisk Users 5 Comments

Hi all,

I seem to be having a strange problem with a sip trunk.

On a fairly frequent basis, I’ll make a call, ore receive a call, and there
will be NO sound. The strange part is that both endpoints are public IP
addresses so NAT isn’t in play and a sniffer trace reveals that the packets
simply aren’t being sent.

It only seems to happen on a particular trunk. The same phone calling on a
different trunk works just fine.

Any ideas?

5 thoughts on - No media being sent in SIP call

  • I’ve turned off t.38 and all of the codecs except ulaw; I still have the same
    problems. SOMETIMES it works. Other times, the sniffer clearly shows that the
    media simply isn’t being sent. NOTHING is being sent.

    Anything else I should check?


  • Hi!

    Look at the firewalls and possible SIP ALGs that are between the devices.
    Check for UDP port forwarding settings, and check that the RTP ports that
    have been negotiated for the call are not conflicting with those of other
    devices/calls/port forwarding settings.


  • There are NO ACL’s in place, either at the network level, or application
    level. We have a public address, so as far as I know, there are no forwarding
    rules in place.

  • Do you have canreinvite=yes anywhere? If yes, try setting it to no. Also
    pasting your sip.conf here would be helpful.

    Zeeshan A Zakaria