[asterisk-users] Error SIP/2.0 488 Not acceptable here

[Matthew Jordan]

----- Original Message ----- 

> From: "Stefan at WPF" <stefan.at.wpf at googlemail.com>
> To: "Asterisk Users Mailing List - Non-Commercial Discussion"
> <asterisk-users at lists.digium.com>
> Sent: Monday, June 18, 2012 4:05:04 PM
> Subject: Re: [asterisk-users] Error SIP/2.0 488 Not acceptable here

> Matthew, thank you very much for the fast reply and very likely the
> solution!
> Using your hint I could locally reproduce the "488 Not Acceptable" on
> my Snom 300 with FW 8.7.3.7 by setting RTP encryption (SRTP) to on
> and RTP/SAVP to off (RTP/SAVP mandatory or SRTP off -> all fine).
> The person calling me has the same phone and FW, so that should
> really be the problem, I will tell him to change it.
> However I am wondering why it's possible to configure a Snom phone in
> such a wrong way at all? Is that necessary for some legacy systems?

I'm not sure why it would be a configuration option.  The 'must' I referred
to comes from Section 6 of RFC 4568.  Its certainly possible that there is
some PBX out there that did not understand a SRTP transport designation.

> Also I am wondering if it's possible to tell asterisk to just ignore
> the crypto line when the profile is just RTP/AVP / not to take
> things that serious? In this specific case I can tell the calling
> person to change the setting, but unfortunately I can't tell this
> every person calling me (not only because they simply can't call
> me).

Asterisk does not currently have a setting for that - if it encounters
a security descriptor in an SDP offer, it will attempt to process it.

--
Matthew Jordan
Digium, Inc. | Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: http://digium.com & http://asterisk.org