Hi Daniel, Removing the sendonly from the INVITE SDP sounds like the most workable solution in our case. We'd only want to do it for a new INVITE though, not a re-INVITE in a situation where a call is put on hold. Would you be able to give an example of such a configuration?
Thanks very much for your help! On Tue, 8 Dec 2020 at 21:56, Daniel-Constantin Mierla <[email protected]> wrote: > Hello, > > if the endpoint is not behind a port forwarding nat/firewall (when one can > instruct the rtp relay to use signaling address), then probably you can try > to remove the sendonly from the INVITE SDP. That will enable rtp from > endpoint to doorbell, which may rise additional concerns (e.g., privacy) if > its is explicitly not wanted to happen. But as Alex said in another > response, the only way to get it work is to make the endpoint behind nat to > send a RTP packet. Usually the doorbells I encountered so far were > accepting incoming traffic as well, to discuss/interact with the person > ringing on it. > > Cheers, > Daniel > On 08.12.20 05:01, David Cunningham wrote: > > Hello, > > We have a problem with a SIP doorbell device which sends media one way > only, and NAT at the receiving device. > > When the doorbell button is pressed it makes a call to a configured > destination. Since the doorbell only sends and doesn't receive it sends the > INVITE with sendonly in the SDP, and the destination then replies with a > 200 OK with recvonly in the SDP. The problem is that the destination is > behind NAT, and its reply contains a private network IP in the SDP. > > Normally Asterisk when nat=yes works around that by adjusting the > destination for RTP to be the address it actually receives audio from, > however because this device is recvonly Asterisk never receives audio from > it. This means Asterisk keeps trying to send the doorbell's RTP to the > private network IP which of course fails, and the destination never gets > the RTP from the doorbell. > > We haven't found a solution in Asterisk to this, so are now looking to > Kamailio which acts as a load-balancing proxy in front of Asterisk for one. > For example, maybe we could use fix_nated_sdp, but only on 200 OK's with > recvonly. > > Has anyone else encountered this, and are there any recommended solutions? > > Thank you in advance! > > -- > David Cunningham, Voisonics Limited > http://voisonics.com/ > USA: +1 213 221 1092 > New Zealand: +64 (0)28 2558 3782 > > _______________________________________________ > Kamailio (SER) - Users Mailing > [email protected]https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > > -- > Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- > www.linkedin.com/in/miconda > Funding: https://www.paypal.me/dcmierla > > -- David Cunningham, Voisonics Limited http://voisonics.com/ USA: +1 213 221 1092 New Zealand: +64 (0)28 2558 3782
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