[SIPForum-discussion] Major issues with TLS-ports

[Franz Edler]

Hi experts,

Maybe anyone might help me to clarify the following problem:

I made some tests using TLS between a SIP client and a SIP server (Proxy and
Registrar). Thereby I observed the following very strange behaviour: 
When the client sets-up the TLS connection selecting e.g. 10.0.0.1:1772 for
the TLS connection it uses a different port in Via and Contact header field
(10.0.0.1:1766) of the REGISTER request. The result is now that for an
incoming SIP session the SIP proxy server uses the port advertised in the
Contact of the REGISTER request (10.0.0.1:1766) but there is no TLS
connection available.

This makes me very confused. I first assumed it is a bug in the client, but
now I tried several clients and every time the same behaviour: The
port-number used in the Via and Contact header field of the REGISTER request
is not identical with the port where the TLS connection has been set-up.

I can send some trace-files if requested.
The clients I used are (Eyebeam, Bria and Mercuro).

Any help highly appreciated.

Regards
Franz