First of all I would like to say I am very curious about the features of Radmin server version 3.0.
I have the following two questions:
1. I would like to use two factor authentication with Radmin, for example with a certificate or hard/soft token. Is this possible with Radmin Server version 3.0 or is this possible in future releases?
2. Currently, I use Radmin with ip filtering, but what I don't like is that Radmin always listens on the Internet even when I am not using it. I would like to trigger Radmin so that it starts listening when I would like to use remote control. Can you give us more detailled information about the "call back" feature in Radmin server 3.0? Does this solve my problem?
I think Hendrik is thinking of having a known secret hash file, one that you would create from your server side via selected option, then you would copy that file to your RAdmin receiver client folder, thus all client connections start with encryption with no PP handshaking thus you have both hard and soft authentication.
I know you've probably gone on to look for other solutions by now. But there is a sort of "workaround" way you could do what you asked about: VPN.
If you create a VPN with the appropriate security settings, you could set up a two-factor authentication for RAdmin: one factor being the authentication of the VPN connection, the second factor being RAdmin's native authentication (or NT authentication). This might be a bit cumbersome, but it would provide the security you're looking for, and could be streamlined with a bit of tinkering and scripting.