Re: [Linphone-users] Linphone call over SSH tunnel; RTP not connecting

[Stuart Gathman]

On 07/28/2017 11:12 AM, Stuart Langridge wrote:
> Hi! I'm trying to make a point-to-point voice (not video) call from
> linphone on one machine (call this machineA) to linphone on machineB.
> I don't have a sip server and don't want to require one for this. I
> can happily, on machineA, call address@hidden and this works
> perfectly for testing. However... machineB is actually only available
> via SSH. I can ssh into machineB from machineA, and I can forward
> ports both forward and backwards along this SSH connection. Which
> ports do I need to forward, and in which directions, to enable a SIP
> voice call?
You really don't want to do SIP over tcp.

Can you run cjdns on both machines?  It needs just one UDP port, and
works fine behind NAT.  Then, just use the IP6 address cjdns assigns to
each machine as the "phone number" for direct dialing with no sip
server.  I do this all the time. 

You don't need cjdns if both machines have an IP6 address - just set
linphone to IP6 mode (it's annoying that it can't do ip4 and ip6 at the
same time) and use the IP6 address.  But cjdns gives you a permanent IP6
that goes wherever the machine goes, and is available even when the
local wifi only provides IP4, and works behind IP4 NAT.

Why is machineB only available via SSH?  Firewall?  NAT?

If there are only a few machines you might want to call (e.g. only those
two), then you can use a traditional vpn like openvpn.  This is actually
somewhat more efficient on a point to point connection than cjdns - but
you don't get the mesh routing.

As to ports, you need 5060 in both directions, and you can pick the
linphone "use fixed RTP port" option for the audio and video, and you
open those ports as well.  (With dynamic RTP ports, your firewall needs
to inspect the SIP packets to determine the RTP ports to open.  There is
an iptables module for this on linux.)