[OpenSIPS-Users] URGENT: contact header changed between opensips and client

[Newlin, Ben]

Something in between is manipulating the addressing in the SIP message. You said that ALG was disabled in the router, but either that is incorrect or there is some other piece of equipment changing the message.

This is clear because the contact is not the only header that is changed. The ‘received’ parameter of the Via address was also changed from the public address of the UA to the private address. Only an entity within the private network could know that address, so it is almost certainly the router doing it.

Ben Newlin

From: users-bounces at lists.opensips.org [mailto:users-bounces at lists.opensips.org] On Behalf Of Satish Patel
Sent: Thursday, April 09, 2015 10:13 AM
To: OpenSIPS users mailling list
Subject: Re: [OpenSIPS-Users] URGENT: contact header changed between opensips and client

Any thought guys? Why contact address change in transit? is it normal?

On Wed, Apr 8, 2015 at 12:12 PM, Satish Patel <satish.txt at gmail.com<mailto:satish.txt at gmail.com>> wrote:
Very interesting thing going on between opensips and my client [UA]

Opensips sending following contact header to Client but on client side i check it received different contact header, who is changing it?

[UA]-----[Opensips]------[FS]

UA - 173.xx.xx.xx.215
Opensips - 182.xx.xx.164:5060
FS - 182.xx.xx.162:5061

My UA behind the NAT and I have ALG disabled on router.


* [Opensips] sending following packet SDP OK 200 to [UA]

2015/04/08 07:42:22.820354 182.xx.xx.164:5060 -> 173.xx.xx.215:49152
SIP/2.0 200 OK
Via: SIP/2.0/UDP 173.xx.xx.215:49152;received=173.xx.xx.215;rport=49152;branch=z9hG4bKPjHB6245E6-SpIsEUs.kPIxxNAFMM0HTDo
Record-Route: <sip:182.xx.xx.164;lr;ftag=OdSDiepaL9YssVLqOv.3C82QrrsrrdUV;did=3fd.556edf93>
CSeq: 722 INVITE
Contact: <sip:1646327XXXX at 182.xx.xx.162:5061;transport=udp>



* [UA] Received following packet, look at Contact:  it changed here. 162 to 164.

U 182.xx.xx.164:5060 -> 192.168.1.9:60895<http://192.168.1.9:60895/>
IP/2.0 200 OK.
Via: SIP/2.0/UDP 173.xx.xx.215:49152;received=192.168.1.9;rport=49152;branch=z9hG4bKPjHB6245E6-SpIsEUs.kPIxxNAFMM0HTDo.
Record-Route: <sip:182.xx.xx.164:5060;lr;ftag=OdSDiepaL9YssVLqOv.3C82QrrsrrdUV;did=3fd.556edf93>.
CSeq: 722 INVITE.
Contact: <sip:1646327XXXX at 182.xx.xx.164:5061;transport=udp>.

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