[SR-Users] SIP contact header question

[Emmanuel BUU]

For a SIP proxy, the preferred method is indeed to add a Record-Route

In the script, add record_route(); instruction.

Emmanuel
IVèS


Le 2017-03-02 à 20:03, Robert Johnson a écrit :
> I seem to recall reading something stating that you shouldn't modify 
> the contact header - But, I can't find the text.
>
> Might suggest adding a Record-Route header instead of re-writing the 
> contact header?
>
> I'm curious as to what the list has to say about this question, I've 
> considered doing the same thing.
>
> On 03/02/2017 04:53 PM, Jack Davis wrote:
>> Greetings,
>>
>> I have a general question about the usage of SIP contact headers in the
>> context of using Kamailio as a SIP proxy.
>>
>>
>> ________________________________
>>
>> [  A  ] --> [  Kamailio  B ]  ---> [  C ]
>>
>> Node A originates a SIP invite, containing a valid via header and URI
>> while setting the contact address to a user at itself and delivers it to
>> Kamailio B which is acting as a SIP proxy.
>>
>> Kamailio B then uses dispatcher routing to direct the Invite to node C,
>> adding a via line with its own information as well as a record-route
>> header with its own proxy information but retaining the same contact
>> address from A.
>>
>> Node C establishes the call and then sends a re-invite to the Kamailio B
>> proxy which is in turn sent to Node A. Node A responds with a 200 OK
>>
>> The problem arises when Node C tries to send an Ack in response to this
>> 200 OK. The ack is being sent to the Contact address, rather than the
>> routing already established in the initial dialog.
>>
>> ________________________________
>>
>> My question is: should kamailio be rewriting this contact address with
>> its own? Is that the best practice? My understanding is that the contact
>> header is more so related to future requests within the same dialog ONLY
>> when a record-route is not used.
>>
>> I would appreciate any clarification on the RFC or best practices in
>> this scenario.
>>
>> Thank you,
>> Jack Davis
>>
>>
>> _______________________________________________
>> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
>> sr-users at 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 at lists.sip-router.org
> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users