22 Jun
2011
22 Jun
'11
1:30 p.m.
Hi!
Just a small survey: Are you still using NAT detection checks? I prefer
to apply NAT traversal always (never trust the contact header) which of
course only works if all the clients are symmetric.
Thus - do you still see asymmetric SIP clients?
Thanks
Klaus
22 Jun
22 Jun
1:36 p.m.
A lot of Cisco (not linksys) SIP equipment is asymmetric.
On Wednesday 22 June 2011, Klaus Darilion wrote:
Hi!
Just a small survey: Are you still using NAT detection checks? I prefer
to apply NAT traversal always (never trust the contact header) which of
course only works if all the clients are symmetric.
Thus - do you still see asymmetric SIP clients?
Thanks
Klaus
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
1:54 p.m.
So what do you use as nat_check? Only the received IP address?
regards
Klaus
Am 22.06.2011 15:36, schrieb Sergey Okhapkin:
A lot of Cisco (not linksys) SIP equipment is
asymmetric.
On Wednesday 22 June 2011, Klaus Darilion wrote:
Hi!
Just a small survey: Are you still using NAT detection checks? I prefer
to apply NAT traversal always (never trust the contact header) which of
course only works if all the clients are symmetric.
Thus - do you still see asymmetric SIP clients?
Thanks
Klaus
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
2 p.m.
I use a separate IP address to accept calls from such SIP clients and do not
check for NAT on those calls.
On Wednesday 22 June 2011, Klaus Darilion wrote:
So what do you use as nat_check? Only the received IP
address?
regards
Klaus
Am 22.06.2011 15:36, schrieb Sergey Okhapkin:
A lot of Cisco (not linksys) SIP equipment is
asymmetric.
On Wednesday 22 June 2011, Klaus Darilion wrote:
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users Hi!
Just a small survey: Are you still using NAT detection checks? I prefer
to apply NAT traversal always (never trust the contact header) which of
course only works if all the clients are symmetric.
Thus - do you still see asymmetric SIP clients?
Thanks
Klaus
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
_______________________________________________
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
sr-users(a)lists.sip-router.org
http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users 
11:45 p.m.
2011/6/22 Klaus Darilion <klaus.mailinglists(a)pernau.at>at>:
Just a small survey: Are you still using NAT detection
checks? I prefer
to apply NAT traversal always (never trust the contact header) which of
course only works if all the clients are symmetric.
I would like to tell a recent issue I've suffered in my company:
- Kamailio with public IP and optional rtpproxy server.
- Two users behind same NAT.
- Both users use STUN so announce public IP:ports in headers and SDP.
- User A calls to B.
- Kamailio does not detect NAT (due to STUN) so doesn't apply
rtpproxy, neither when routes the call to user B.
- So user A sends RTP to the public IP of its NAT router, same as user B.
- In some routers this work, but in this case it does not properly
perform NAT port forwarding and there is no audio.
Solutions:
1) Remove STUN from clients (not always feasible).
2) Always use RtpProxy. Easier.
Thus - do you still see asymmetric SIP clients?
Yes, I've seen some Alcatel OXO using asymmetric SIP. A pain if you do
"force_rport".
Solution:
- Just perform "force_rport" if the client is detected as behind NAT
(note that assymetric SIP clients can ***NEVER*** run behind NAT).
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
4710
days inactive
4710
days old
4 comments
3 participants
participants (3)
-
Iñaki Baz Castillo -
Klaus Darilion -
Sergey Okhapkin