Hello all,

I'm using Kamailio as a registrar and i have an endpoint that sometimes sends a REGISTER method with a To-Tag when refreshing its regist. My code on this proxy shares many similarities with the default kamailio.cfg configuration file.

On that occasion Kamailio answers with a 404 - Not Here since it treats it as a in-dialog request which fails the loose_route check.

Why would a CPE send a REGISTER with a To-Tag? Why is a REGISTER with a To-Tag rejected by Kamailio when it could otherwise be a successful REGISTER? Is this behaviour noncompliant with the SIP protocol?

I thought about making an exception in the code and having this register following the same path as a register without to-tag, but i don't know if that is unsafe and/or noncompliant with the protocol.

Best Regards,