12 Nov
2004
12 Nov
'04
11:02 a.m.
On Nov 11, 2004 at 00:04, Thomas <thomasj(a)eworld.hu> wrote:
Hello!
I'm trying to make my 1st SIP-based system working. I use SER-0.8.14
on Linux Sarge. I have usually UAs behind NAT firewalls.
I found a case, when UAs are working very oddly, I can't call from one
of them, after sime time I can't reach one of them from outside, after
some time when I call one UA, the 2nd is answering (and the same time
when I call 2nd UA, the 2nd is answering).
I have 2 UAs [Grandstream BT100 & X-Lite v2.0] behind a linux NAT
firewall. Both UAs use the same STUN and SER server.
I did some tcpdumps and I found an interesting thing:
Internet Protocol, Src Addr: <FWPUBLICIP> (<FWPUBLICIP>), Dst Addr:
<SERIP> (<SERIP>)
User Datagram Protocol, Src Port: 1024 (1024), Dst Port: 5060 (5060)
Session Initiation Protocol
Request-Line: REGISTER sip:<MYDOMAIN> SIP/2.0
Method: REGISTER
Resent Packet: True
Suspected resend of frame: 31
Message Header
Via: SIP/2.0/UDP <FWPUBLICIP>;branch=z9hG4bK0dbeeb499dbd416e
[...]
What is interesting is that REGISTER message went out
from port 1024
but 200 OK came to port 5060. Is this OK? I think here is some problem
and this can make the phones working oddly.
If the phone wanted the answer on 1024, it should have advertised it in
the REGISTER's via. A least it should have added a rport parameter to
the Via.
You can try using force_rport() in ser config for all requests (or for
requests comming from this phone). This might break asymmetric UAs
though (not very common these days).
Andrei