Scenario
This article describes how to create a secure network-level transport between two hosts. All traffic sent between both hosts will be encrypted automatically as in enters the TCP/IP stack at the network (IP) level by using IPSec Encapsulating Security Payload (ESP) protocol.
For more details about IPSec, read IPSec pilot between glass and teapot.
Security Policy Database [...]

From the stunnel manual page:
The stunnel program is designed to work as SSL encryption wrapper between remote clients and local (inetd-startable) or remote servers. The concept is that by having non-SSL aware daemons running on your system you can easily set them up to communicate with clients over secure SSL channels.
stunnel can be used to [...]

SSLTunnel is a beautiful piece of software used to create an SSL/TLS VPN between two hosts, usually a client host and a VPN concentrator or server. Inside this tunnel, the traffic between the client and the server gets encapsulated inside PPP frames which are encapsulated inside the SSL/TLS tunnel. The tunnel itself is built using [...]