[Freeswitch-dev] Automatic hangups?

Michael Collins msc at freeswitch.org
Thu Apr 7 01:28:43 MSD 2011

On Wed, Apr 6, 2011 at 2:15 PM, Mark Sobkow <m.sobkow at marketelsystems.com>wrote:

> We've tried several different softphones: Phoner (SIPPER stack), X-Lite,
> and our internal M-Phone (I forget what SIP stack implementation that
> uses, as I didn't write it.)  All exhibit the same problem.
> Our network admin insists it's not a network problem.  As we hadn't had
> this problem previously, I can't argue with him over it.
> I'm a little unclear about what is supposed to be sending the ACK -- the
> softphone, FreeSwitch, or our application code.

This is typical SIP traffic, so the UA sending the INVITE should be ACKing
the appropriate responses from FS. In your case, FreeSWITCH sends a 200 OK
several times, indicating that the phone has answered the INVITE. However,
FS is not receiving the required ACK from the UA so it gives up and sends a

So, what Tony said is correct - for *some* reason the ACK is not making it
back to FreeSWITCH. This is *not* a problem with FreeSWITCH, it's a problem
on the network or with the originating UA.

Are you able to confirm that the UA is seeing the 200 OK from FreeSWITCH?
That sounds like a reasonable first place to troubleshoot.

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