Summary:ASTERISK-19089: faxdetect=yes in sip.conf general overrides faxdetect=no in peer configuration
Reporter:Steven Wheeler (swheeler)Labels:
Date Opened:2011-12-20 13:22:30.000-0600Date Closed:2012-01-30 11:27:09.000-0600
Status:Closed/CompleteComponents:Channels/chan_sip/T.38 Core/Configuration
Versions: Frequency of
Environment:CentOS release 5.7 (Final), Asterisk 0) fax_detect_cli_show.diff
Description:When faxdetect is set to yes in the general section of sip.conf no peers can ever disable it.  This is causing issues for us because we want to detect faxes on channels that don't belong to a peer, but still want to disable faxdetect for peers which are ATAs connected to fax machines.

faxdetect=yes; <-- enable fax detection on non-peer channels

faxdetect=no; <-- does nothing, faxes are still detected.
Comments:By: Stefan Schmidt (schmidts) 2012-01-10 01:15:15.739-0600

1.8 doesnt take care of the peers fax detect option, only the global one. i will attach a patch which is a backport of the channel(faxdetect) option of 10. With this you can enable or disable faxdetect for each call separetly.

By: Matt Jordan (mjordan) 2012-01-10 13:05:23.426-0600

Stefan - I was looking at this as well.  From what I can see, 1.8 (at least in the branch) already does the requisite pulling over of the various SIP fax detect flags from the peer when its supposed to.  What particular changes went into 10 that you're referring to here?

By: Matt Jordan (mjordan) 2012-01-12 13:47:16.590-0600

Stefan - is this the patch you're talking about?


If so, I'm not sure it should go into 1.8.  That was a feature that was developed specifically for Asterisk 10, and isn't fixing a bug.  As it is, 1.8 *should* let a peer override the global faxdetect option (which, if you add some debugging in to the CLI command, you can confirm via sip show peer.)

By: Steven Wheeler (swheeler) 2012-01-12 14:41:00.422-0600

I set debug to 100 and did a sip show peer, there was no mention of fax detection in the output.  The same is true for sip show settings.  These are the only fax related settings I could find:
 T.38 support : Yes
 T.38 EC mode : FEC
 T.38 MaxDtgrm: -1

By: Matt Jordan (mjordan) 2012-01-20 13:11:29.763-0600

I've attached a small patch (fax_detect_cli_show.diff) that does not other then show the faxdetect setting in "sip show peer xxx".  The patch does not change how the faxdetect settings are applied to a peer.

You can use this, however, to verify that the [general] settings are being overridden on a peer-by-peer basis.  However, this may not still do what you want, as the functionality that you are most likely looking for exists in Asterisk 10.  As that was a feature developed for Asterisk 10, it will not be backported to Asterisk 1.8.