Stunnel is a very versatile open-source tool designed to help secure web applications. It encrypts traffic, proxies connections, and redirects web applications so that they can run securely on a computer with untrusted network connections. Stunnel can also inspect every packet within encrypted tunnels and make adjustments to improve performance. Stunnel manages one or more client-server TCP/IP connections by creating an encrypted tunnel through which only the client and server are allowed to speak. This encrypted connection is in lieu of a direct connection between the client’s application and the server’s application, which helps prevent tampering with communications in transit from one end of the connection to another.