asterisk users - Mar 2017 - Logging endpoint IP address when PJSIP registration fails

Hi!

I am seeing a lot of warnings of these types:
res_pjsip_registrar.c: AOR '31' not found for endpoint
'anonymous'

I am guessing these are coming from a scanner trying to scan for the
extensions on the asterisk server.

Is there any way to print the IP address of the endpoint trying to
register an extension using PJSIP in asterisk 13?  I can then configure
fail2ban to temporarily hinder the scan.

Regards,
Sree