On 03 Nov 2015, at 11:29, Marino Mileti <marino.mileti@alice.it> wrote:

I would like to avoid multiple registration with the same AOR...
I know that there's a parameter for this (max_contacts) but if I set it to 1, all REGISTER overwrite location info.
 
Instead i would like to reply with error if a REGISTER arrive with the same AOR just registered on location server.
 
Is that possible? Any help is appreciated J
 
A simple glance at the documentation page for the REGISTRAR shows me a function called “registred”.
http://kamailio.org/docs/modules/4.3.x/modules/registrar.html#registrar.f.registered

"The function returns true if the AOR in the URI is registered, false otherwise. “

If you use that one and refuse a registration if true, you will get exactly what you want.

Reading available documentation is a good thing (TM) :-)

Regards,
/Olle