ive set up an openvpn server at my place and handed out a certificate to a client who has an openvpn client at his place. however i require that he should be able to connect to the vpn server only from one ip(his current one). how can i do this?
Presumably you have a firewall at the perimeter of your network (or on the vpn server at the very least). My suggestion would be to create a firewall rule that allows vpn connections to the server only from his ip address.