From charlesreid1

Pages related to stunnel, a tool for creating encrypted SSL connections with arbitrary traffic on arbitrary ports.

You can use stunnel to do things like wrap SSH or MongoDB traffic in SSL and send it out through port 443 using an stunnel client, bypassing firewalls that only allow HTTP and HTTPS traffic (the firewall can't inspect the contents of encrypted packets so it doesn't know it isn't actually HTTPS traffic). The traffic is then received on an stunnel server, which decrypts the traffic and unwraps the SSL layer, forwarding the traffic on to other services.