[OpenSIPS-Users] problem with uac registration

[lorenzo]

hi!

i'm developing a sip client and i'm new to using opensips (before i
relied on public sip servers)

i'm having some trouble with registering to opensips. i do not think
it's a problem with opensips in itself, but i think you could help me
solve the issue (you've been warned, this may be slightly OT ;) )

when i try to connect to the opensips server using the telephone app[2],
everything goes smooth.
using my app, *sometimes it works, sometimes it doesn't*. i haven't been
able to determine the reason.

here are the wireshark capture of telephone's request:
I.8E4K at mdX.bREGISTER sip:biascica.pipps.net SIP/2.0
Via: SIP/2.0/UDP
93.148.135.32:14810;rport;branch=z9hG4bKPj6oC4Dpa6zNgapScuG75X8tBMdYk.qotP
Max-Forwards: 70
From: "asdomar"
<sip:biascica at biascica.pipps.net>;tag=Pa0-GnWltHWcRSFW9cJAZqP3ut2eBss2
To: "asdomar" <sip:biascica at biascica.pipps.net>
Call-ID: lR8wJZYTbGIyEsVUijltUxafN4.Ce94g
CSeq: 41254 REGISTER
User-Agent: Telephone 0.14.3
Contact: "asdomar" <sip:biascica at 93.148.135.32:14810>
Expires: 300
Content-Length:  0

while this is the capture of my app's request:

REGISTER sip:biascica.pipps.net SIP/2.0
Via: SIP/2.0/UDP 93.148.135.32:5060;rport;branch=z9hG4bK54695
Max-Forwards: 70
To: <sip:asymmetric at biascica.pipps.net>
From: <sip:asymmetric at biascica.pipps.net>;tag=z9hG4bK03393413
Call-ID: 030448912644 at 93.148.135.32
CSeq: 1 REGISTER
Contact: <sip:asymmetric at 93.148.135.32:5060;transport=udp>
Expires: 3600
User-Agent: mjsip stack 1.6
Content-Length: 0

(as you can see, i'm using mjsip[2] as my sip stack)

note that both apps are running on my computer (one is actually running
on the android emulator), and are stun-aware (both are using
stun01.sipphone.com as their stun server).
is there anything that would justify the opensips server not replying to
the latter request?
another, connected problem is that calls from my app to telephone go out
ok, whereas incoming calls, from telephone to my app, seem to get lost.

i can provide opensips logs, but i think they're quite irrelevant, since
when my requests get ignored, there's no mention of them in the logs.


thanks
asymmetric

[1] http://code.google.com/p/telephone/
[2] http://www.mjsip.org