We currently use a mix of Cisco 79xx, Polycom 601, and Cisco SPA series phones in our enviornemnt. The polycom and spa series phone support http provisioning which provides authentication. However, the cisco 79xx phones appear to not support this. If anyone could help it would be greatly appreciated. We have had trouble with hackers trying to brute force sip credentials from our asterisk server and besides blocking them with access lists it would be nice to have to need authentication as well.