On Tue, Jan 15, 2019, at 1:17 PM, Brian J. Murrell wrote: > On Tue, 2019-01-15 at 12:01 -0500, Joshua C. Colp wrote: > > > > The chan_sip module has this implemented under the "nat" option using > > "comedia" as I recall. > > Yeah. The help for which reads: > > Send media to the port Asterisk received it from regardless > of where the SDP says to send it. > > > It causes media to be sent to where media was originally received > > from. > > Right. But this is the part I don't think I'm understanding. What is > "originally received from"? There is no media at the point where the > media session is being set up according the the SDP is there?
It waits until the RTP flows to determine this. > > > As for whether it would work or not... this all ultimately depends on > > how exactly the intermediary behaves, what is let through, what is > > altered. There's nothing inherent in either chan_sip or chan_pjsip > > to know/care, as it's just SIP. You'd need to look at the SIP > > signaling and the SDP to understand what is happening. > > I have looked. Asterisk on my LAN is sending an INVITE to the mobile > client and since the INVITE is being sent to an external IP, it is > (correctly for all other cases) writing the external IP into the SDP > payload. What else could/should I be looking for? > > Ultimately I don't think comedia is the problem or solution because > it's not where Asterisk is sending it's media that is the problem. > > The problem is that Asterisk is sending an INVITE to the client with > it's external IP address in the SDP because it sees the client as being > external and the client is then correctly trying to set up the media > session with the external IP address of the Asterisk instead of it's > internal address. Ah yes... yeah, there's nothing built in to handle the scenario. > What needs to happen is that Asterisk has to know "somehow" that even > though the client registered from an external address, that it really > is internal. Probably that "somehow" doesn't actually exist at this > point. > > Let me ask this, in the REGISTER request, where is the IP address of > the client taken from? Is it taken from the Via: header? For what purpose? The SIP response goes to the source of the request. If you mean the registration address, that is the Contact header. A REGISTER essentially means "I can be reached at this Contact address for requests". -- Joshua C. Colp Digium - A Sangoma Company | Senior Software Developer 445 Jan Davis Drive NW - Huntsville, AL 35806 - US Check us out at: www.digium.com & www.asterisk.org -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- Check out the new Asterisk community forum at: https://community.asterisk.org/ New to Asterisk? Start here: https://wiki.asterisk.org/wiki/display/AST/Getting+Started asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
