Re: [Linphone-users] [Linphone-developers] serverless voip call

[Stuart D. Gathman]

On Tue, 14 May 2019, dinis brazão wrote:

> The useage scenario is:  mobiles in the same wifi network but without access
> to server.
> I am looking for a way to make them call each other without needing a server
>
> User2 would dial address@hidden:5060    targetting directly the
> user 1.
> No need for registration.

Yes, that is the primary way I use linphone.  Using IPv6, you can 
call directly without being in the same wifi network - but as most
wifi (or mobile) routers in the US do not implement IPv6, you have
to install a VPN.  The IPv6 VPN I use is Cjdns - but the app for that
is not in an app store, and has to be installed manually.  I use
laptops.  :-)

In the peer-to-peer setup, the IP becomes the "phone number" quite
literally, instead of a metaphor when trying to explain IP to lay people.

Here is what an IPv6 peer-to-peer sip address looks like:

"John Doe" <sip:address@hidden:1328:adf1:bffe:4b6b:f53f:48ba:1882]>

The port 5060 is the default.

I have linphone-3.6.1, and unfortunately, an underlying library 
recently decided that it didn't like sending certain SIP signalling messages
to a private IP like the above or 192.168.x.x.  It would attempt to send
from a public IP instead, usually resulting in failure (although it
works when the IPs are actually public).

The symptom is that the call works perfectly with audio both ways 
for 30 secs - then gets disconnected when the caller times out waiting
for the call setup acknowledgement.

If your version is having that problem, you need to use public IPs,
which means using a VPN.  Using a public IPv6 via VPN effectively
works around the problem.

--
              Stuart D. Gathman <address@hidden>
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.