Recipe 3.7. Restricting Access by Remote Users

3.7.1. Problem

You want only particular remote users to have access to a TCP service. You cannot predict the originating hosts.

3.7.2. Solution

Block the service's incoming TCP port with a firewall rule [Recipe 2.6], run an SSH server, and permit users to tunnel in via SSH port forwarding. Thus, SSH authentication will permit or deny access to the service. Give your remote users SSH access by public key.