On Mon, Feb 3, 2020 at 7:24 AM Alex Balashov <abalashov@evaristesys.com> wrote:
On Mon, Feb 03, 2020 at 07:17:42AM +0900, mayamatakeshi wrote:

> is it possible to reply with a different expires for a REGISTER depending
> on some condition like the User-Agent?
> I am thinking maybe I can use:
>   $ulc(profile=>expires) = 600

Expiration is ultimately in the hands of the registrar, and the
registrar is free to reply with an expiration different to what the
registrant has requested.

Expiration policy is generally controlled by:

   https://kamailio.org/docs/modules/5.3.x/modules/registrar.html#registrar.p.min_expires

   https://kamailio.org/docs/modules/5.3.x/modules/registrar.html#registrar.p.max_expires

and some related modparams near the top.

As far as I am aware, there is no way to override the expiration
decisions of the registrar in a custom way.


I think you are right. 
I will try a different approach that is to enlarge the allowed registrar expires range using the above parameter and then change the value of the Expires in the REGISTER message before passing it to registrar module.
Thanks.