Hello,

On 8/3/12 1:43 AM, Varsha Venkatraramani wrote:

I have a question regarding the below ACK response Kamilaio
receives from a carrier.Can  someone please help me understand why
the "*Route: sip:callmanager@192.168.160.43:5060> *sent from
Kamailio is missing a "<" as shown in the captures below? Our
Internal proxy is treating that as a malformed header and dropping
the packet.

*ACK from CARRIER*

U 2012/08/01 18:32:52.219852 4.55.18.227:5060
<http://4.55.18.227:5060> -> 192.168.160.47:5060
<http://192.168.160.47:5060>

*ACK sip:callmanager@192.168.160.43:5060 SIP/2.0.*

Via: SIP/2.0/UDP 4.55.18.227:5060;branch=z9hG4bK04B0eef33040e9b8e70.

From: sip:+14088442721@4.55.18.227:5060;tag=gK043001e3.

To: sip:+19728931740@192.168.160.47:5060;tag=b307370c678f3b44.

Call-ID: 295226_50030734@4.55.18.227
<mailto:295226_50030734@4.55.18.227>.

CSeq: 18079 ACK.

Max-Forwards: 70.

Route: <sip:192.168.160.47:5060;lr=on>.

*Route: <sip:2c6c6d1ab58c623912f6b8a6ee526982@192.168.160.44:5060>.*

Content-Length: 0.

.

*ACK FORWARDED TO SIP PROXY*

U 2012/08/01 18:32:52.220612 192.168.160.47:5060
<http://192.168.160.47:5060> -> 192.168.160.44:5060
<http://192.168.160.44:5060>

*ACK sip:2c6c6d1ab58c623912f6b8a6ee526982@192.168.160.44:5060
SIP/2.0.*

Via: SIP/2.0/UDP 192.168.160.47;branch=z9hG4bKcydzigwkX.

Via: SIP/2.0/UDP 4.55.18.227:5060;branch=z9hG4bK04B0eef33040e9b8e70.

From: sip:+14088442721@4.55.18.227:5060;tag=gK043001e3.

To: sip:+19728931740@192.168.160.47:5060;tag=b307370c678f3b44.

Call-ID: 295226_50030734@4.55.18.227
<mailto:295226_50030734@4.55.18.227>.

CSeq: 18079 ACK.

Max-Forwards: 69.

Content-Length: 0.

*Route: sip:callmanager@192.168.160.43:5060>.*

I have attached the config file for you reference. Kamailio
version is 3.2.3

the next proxy does strict routing, because the Route header has not 'lr' parameter. Based on SIP specs, Kamailio has to take that route and set it as r-uri and the r-uri has to be added as last route, so next proxy will be able to do forwarding based on strict routing rules. Maybe there is an option in that device at 192.168.160.44 to do loose routing, which is the recommended one in RFC3261 (strict routing is from the old rfc of SIP).

Regarding the missing '<' in the Route header sent out from Kamailio, there was an issue in the code handling this specific situation, should be fixed now by commit: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=cbb62f86...

You have to apply that patch or use the latest git branch 3.2. Let us know if works fine.

Cheers, Daniel