it seems that snom Firmware 10, at least 10.1.39.11, which I tested things with, does not create correct authentication digests (??). Manually calculating the authentication digest for the REGISTER request (I get the data through the SIP logging of the phone) always leads to different digests than what the phone sends, and the remote SIP server (Asterisk) also rejects the authentication with a 403 Forbidden (i.e., password wrong).
I'm somewhat hesitant to post the actual authentication requests, as I'd have to set up a dummy account for there to be no authentication data leakage to a forum, but if required, I can happily do that. Anyway, I'm positive that all authentication info the phone sends back looks correct (i.e., nonce correct, URI correct, it's just the digest).
Is this a known problem (i.e. because of some specific formatting of username or password or nonce, which leads to invalid results in the digest calculation)? I can't for the life of me think that this is a general problem with the phone, but rather possibly something in the setup that I am deploying the snom in.
Thank you for any insights.
Topic converted to ticket.