Re: [Linphone-developers] wrong local address and proxies and routes

[Nomad Arton]

Dear Simon,
> This IP address is determined by retrieving the local address that
> can connect to the internet.

I think the method is too simple to match multihomed systems: linphone 
2.11 would take the address of whatever interface got used to connect to 
217.12.3.11. See Debian bug #500512. I cannot find this address in the 
current trunk linphone source available from svn.savannah.gnu.org - did 
the method change? The letter from Jun Yin states that the outcome 
remained the same in 3.0.0.

I do not understand what you said about double registration. Below again 
just what occured to me. A small drawing:

Host L, where linphone runs, can reach host R, the registrar, via two 
different routes: through hosts X, and Y. X is L's default gateway, but 
its just a dumb nat router, while Y is a smart router, that can take 
care of mangling sip messages and rtp-proxying! in fact, L takes part in 
two local networks, with different interfaces and different local 
addresses (a common VPN scenario).

  ---------- X --------
L                       R
  ---------- Y --------

To find the correct local address, linphone might first try and connect 
to the host named "route" in preferences (here Y), if none, to the host 
named "proxy" in the preferences (here R), and only as a last resort 
should use the system default route (here through X).

Its ok to use the address of the interface that getsockname from a 
connect to eg. Y returns.

> For the second one, I don't understand how linphone could use a different 
> address in registers and in invites. A log file would help.

Also with 2.11: It does not do that. It uses the same IP-address. Yet, 
in above scenario, registers and invites take different routes. I 
learned that from looking at wireshark.

When a route is specified in the proxy configuration, INVITEs will go 
out over the interface the kernel uses to connect to that host (Y), 
while the REGISTER message on startup will go out over the default 
interface.

The REGISTER should also go through the proxy, shouldnt it? The proxy 
then can swap the local address with the public address in the sip 
messages, and voila, somebody can call me from the info the registrar 
will provide them;)

Regards! Peter