Challenge 401 response

 

user is registered via SBC to registrar server. SBC has user information in its cache.

If the same user sends new registration , Registrar challenges it with 401. User did not send digest authentication 

and thus Registrar never sent 200 OK to SBC and SBC to client.

 

But when client sent an INVITE , SBC accepted it. Shouldn't it have replied with 403 forbidden ?

 

If user does not reply with digest authentication to 401 challenge , is it still maintained in SBC cache.

 

Thanks