pptp vpn - Kill User Connection

I'd like to be able to terminate a user's connection to my pptp server from the server itself without interrupting anyone else's connection. Problem is - I have no idea how and have found no useful information via the usual channels (google, basically).

Any help is much appreciated!

Edit I'm using Debian.

Assuming this is a Windows PPTP server we're talking about, you can go to Administrative Tools->Routing and Remote access and then select "Remote Access Clients" on the left. From there, you can disconnect them.

I'm using Ubuntu as PPTP-VPN Server.

1. last | grep ppp | head to show current connected clients.
2. ps aux|grep pptpd to show connected clients's pid and assigned ip.
3. killall pppd to kill all client's connection
4. kill $pid to kill specific client and disconnect it.