Stunnel

Stunnel is a cool open-source command-line tool that helps you encrypt your TCP connections, whether they're local or remote. It does this using SSL encryption to keep data safe between the client and server.

What Can Stunnel Do?

This software is super handy for adding SSL features to IMAP and POP2/3 daemons. To support different cryptographic methods, Stunnel relies on the SSLeay and OpenSSL libraries.

Security Features of Stunnel

Stunnel is FIPS 140-2 validated, which is part of the OpenSSL FIPS Object Module. You can find it in the default software repositories for many Linux-based systems. Plus, it supports various types of sockets like IPv6, poll, or systemd.

How to Install Stunnel

If you want to install Stunnel on your GNU/Linux operating system, start by downloading the latest version from Softpedia. It comes as a universal sources archive. Just save it wherever you like, extract the files, and open a terminal window.

Compiling Stunnel

Once you're in the terminal, type in “./configure && make” to set up and compile Stunnel for your hardware and OS (it works with both 32-bit and 64-bit architectures). After it's done compiling successfully, just run “make install” as root or with sudo (no quotes needed).

Configuring Your First Run

The first time you fire up Stunnel, it will look for its configuration file at /usr/local/etc/stunnel/stunnel.conf. You can use a specific config file or read one from a file descriptor if you prefer.

A Bit About Its Code

Stunnel is written completely in C programming language and comes as a universal sources archive so you can tweak it for your GNU/Linux system. It's been successfully installed on both 32-bit and 64-bit machines!