9 Apr
2007
9 Apr
'07
4:50 a.m.
The client does not have STUN support. (I am not sure; because there is no field to enter
stun server address. However it may have an internal STUN)
Actually the client is the "internet calling" feature of new Windows Mobile
6.0.
I am also nearly sure that there is no ALG in front of the UA. Plus, I am using 5061 on
the SIP server as UDP port. So most of the ALG mechanisms do not mess with my sip
messages.
I believe this is a misconfiguration issue. But I don't know how to troubleshoot it.
Any help on the nat configuration would be wonderful.
Thanks,
ilker
________________________________
From: Greger Viken Teigre [mailto:greger@teigre.com]
Sent: Monday, April 09, 2007 11:25 AM
To: İlker Aktuna (Koç.net)
Cc: serusers(a)iptel.org
Subject: Re: [Serusers] interesting 2 way SIP signalling problem
Most likely the invite is not detected as NATed by your config and force_rport and
fix_nated_contact (which will solve your problem) are not called.
If you use stun, it behaves badly. If not, you have an ALG in front of the UA.
g-)
------- Original message -------
From: İlker Aktuna (Koç.net) <ilkera(a)koc.net>
Sent: 9.4.'07, 9:32
Hi,
I have a working configuration on my SER server. Most of the users can make calls (both
way incoming and outgoing) with no problem.
However, I have some clients that can't make calls.
When I analyze these by ngrep and/or tcpdump, I see that the SER server does not reply
the packet on the correct port.
For example, I have a testing client which is behind NAT.
The client sends INVITE message from UDP port 3023 to port 5061 of my SER.
(cseq number is 1)
SER exchanges the message with the uplink sip gateway and when it receives a
"OK" response it forwards this message to the client's NAT IP address BUT on
a different port (14640) with correct cseq number (1)
Of course, this new port is not open on the NAT router and it does not reach the client.
I see that the first INVITE message has Contact field with internal IP address of the
client and the port number as 14640.
So the SER server sends the returning message to the external IP address with internal
port number.
How can I fix this issue ?
I can send the configuration of my SER server if that would help to find the problem.