I have been researching this exact issue, and the only solution I have found to assign static IPs to PCs is to create a unique VPN group for each, or to use the Windows PPTP client. Options that I have pursued with no luck:
- Static assignment on the local PC: The only way to do this is by using the native Windows PPTP client. The Cisco VPN client does not support static IP assignments.
- Static DHCP assignment based on PC: The concentrator does not support static assignments with its local DHCP server, and when it passes DHCP requests to an external server, it uses a random MAC and no hostname for the initial request as best as I can tell.
- Assignment based on user name: This works with an external radius server that can return an IP address as one of the user's radius attributes.
I hope this helps clarify the situation. I am hoping that Cisco adds support for static IP assignment per host in the future, as it would be easy to implement and very useful.