[Spce-user] 400 Normal Release

[Jon Bonilla (Manwe)]

El Thu, 18 Oct 2012 18:50:30 +0200
Jon Bonilla (Manwe) <jbonilla at sipwise.com> escribió:

> I'm sorry but looks like the error comes from sems somehow. We'll need the
> ngrep including the communication between the proxy and sems and the sems log
> with debug enabled.
> 
> sems-stats -c "set_loglevel 3"
> ngrep-sip b port 5060 or port 5062 or port 5080 -q
> 

Ok. Thanks for the logs and thaks to sems developers (Frafos GbmH) and Andrew
Pogrebennyk for taking a look to the logs. It was easier than expected but I
didn't see it (shame on me!)

The invite we send to the peer is as follows:

U 2012/10/18 12:55:34.746152 SPCE_IP:5060 -> PEER_IP:5060

INVITE sip:19057722572 at PEER_IP:5060;transport=udp SIP/2.0'
Record-Route:
<sip:SPCE_IP;r2=on;lr=on;ftag=4BA41CEB-50803486000B6042-82053700;ngcplb=yes>'

Record-Route:
<sip:127.0.0.1;r2=on;lr=on;ftag=4BA41CEB-50803486000B6042-82053700;ngcplb=yes>'


And the 183 we get back from the peer is like this one:

U 2012/10/18 12:55:36.555972 PEER_IP:5060 -> SPCE_IP:5060
SIP/2.0 183 Session Progress'

Record-Route:
<sip:SPCE_IP;r2=on;lr=on;ftag=4BA41CEB-50803486000B6042-82053700;ngcplb=yes>'

Record-Route:
<sip:PEER_IP:5060;r2=on;lr=on;ftag=4BA41CEB-50803486000B6042-82053700;ngcplb=yes>'



It looks like the peer is substituting it's own IP address
PEER_IP:5060 where 127.0.0.1:5060 should be sent in the record-router header.
Due to that, sems can't route the ACK back when the call is answered and the
peer releases the call with a 400 (This is also something I've never seen
before) response. 

We've seen this behaviour in some Audiocodes gateways before and that a wrong
behavious from your peer server.

You have two choices: Report the behaviour to your peer and expect them to
solve their bad behaviour or you can change the internal ip address of you
sip:provider from 127.0.0.1 to something else (networking.iaddress in
config.yml) to something else. Create a dummy interface with some private ip
address and set that parameter to that value. I would do both :)