Camille, Don't waste your time on this topic. Apparently this is "normal" behavior and the thing we're trying to do is just a violation of existing specifications. 3rd party registration is done on ISC level and can't be modified in configuration. Anyway, I will jump deeper into specification and try to find the way we should be achieving this goal. thank you Dan On 02/05/2014 05:16 PM, Daniel Ciprus wrote: Camille, Thanks for quick response. Yes, this is 3rd party registration. Unfortunately this (according to specs I listed below) shouldn't happen. Is there any workaround except messing around with textops and replacing things in Contact: ? I will need to add optional parameters from original REGISTER to 3rd party REGISTER, that's the goal. Dan On 02/05/2014 02:16 PM, Camille Oudot wrote: Le Wed, 5 Feb 2014 12:13:17 -0500, Daniel Ciprus <daniel.ciprus@acision.com><mailto:daniel.ciprus@acision.com> a écrit : For our application to work we'd like to see not modified Contact: from Kamailio being sent towards our AS. Unfortunately this is not happening now. Below are REGISTER messages from client and message which is sent to AS. I wasn't able to find any logic in .cfg file so I thought this would be the place where I should post my problem. According to 3GPP TS 24.229, RFC 3261, RFC 5626 it seems like this is not the behavior which should be happening. Hi Daniel, This looks like a third party register sent on the ISC interface. AFAIK, the behavior you are seeing is normal. The original REGISTER is not proxied: a new dialog between S-CSCF and AS is started instead (the S-CSCF becomes the UAC). The IMPU of the user that is triggering the third party register cans be seen in the To: header field, and the original Contact URI info is lost. Regards -- Daniel Ciprus Integration engineer http://www.acision.com 9954 Mayland Dr Suite 3100 Richmond, VA 23233 USA T: +1 804 762 5601 E: daniel.ciprus@acision.com<mailto:daniel.ciprus@acision.com> ________________________________ This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you for understanding. -- Daniel Ciprus Integration engineer http://www.acision.com 9954 Mayland Dr Suite 3100 Richmond, VA 23233 USA T: +1 804 762 5601 E: daniel.ciprus@acision.com<mailto:daniel.ciprus@acision.com> ________________________________ This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you for understanding.