Hi
Sark provisioning works with snom 821 but there is no 821 template in the db. However, it's easy to create one; go to the templates panel and add a new template. Call it Snom 821 (note the upper case S and the single space) and copy the Snom 820 template. Now edit your new template and change the first line of the provisioning file to be
["snom821-$MAC.htm"
Add another template. Give it a name of snom821.htm (all lower case) and copy snom820.htm.
You can now provision a Snom 821 using either TFTP or PnP provisioning. To use TFTP then your DHCP server will need to offer Option 66 and point at the SAIL box or you can manually set the provisioning server address into the phone
Alternatively, with Snoms you can use PnP provisioning in which case you won't need DHCP. To use PnP, enable PnP provisioning in globals, the Snoms will just use use it.
I also notice you want to run the Snom using the VPN version of their firmware. This works OK and we've used it a few times however, it is not particularly easy to set up. There is a howto on the Snom wiki.
http://wiki.snom.com/Networking/Virtual_Private_Network_(VPN)
The only other thing is that you will have to define the VPN subnet to SME server as a local network.
We have a customer running a bunch of Snom 820s like this and they run OK and, of course, are very secure.
Kind Regards
s