Media for Looking for a radius server with specific specs

Hi there,

I'm looking for a software based radius server that will be accounting my vpn users with the following specs:

- Must be able to allow/deny vpn based on source ip of the clients

- Must be able to have time limits

- Must be able to run on windows

- Would be nice if its scriptable, so I can build my own webinterface around it

- Would be nice if it could use LDAP

I've been looking around a but but havent really found a easy solution yet. Is there such a radius server around? Preferably not too expensive :P

Regards,

M3ph