stunnel For Mac

Using SSL encryption to secure the connection between a remote client and the server is highly advisable. stunnel is a command line utility for the macOS that can be used to add SSL (Secure Socket Layer) capabilities to your transfers.

stunnel does not come as a binary: to be able to use it you must download the source package and compile the utility via the Terminal.app. After opening a Terminal window, make sure you navigate to the stunnel folder and then use the “./configure && make && make install” command (without the quotes) to build the tool from source.

Note that you must have installed beforehand the Command Line Tools that come with Apple's Xcode IDE to be able to complete the installation process.

To work properly, stunnel requires a configuration file that must include a connection address (IP addresses that can be separated by a colon) and a port number. The user has to create these configuration files manually.

stunnel is able to grant access to the server by using SSL certificates and includes support for CRL and OCSP certificate annulment. Other capabilities involve the fact that stunnel can deal with the SNI, PFS, and FIPS protocols.

You can use stunnel to secure applications that are using various types of protocols, such as SMTP, POP3, NNTP, CIF, PROXY, CONNECT, or IPv6. At the same time, if the authentication fails, stunnel is able to redirect the SSL client.

stunnel proposes a simple solution for adding SSL encryption to your client to server connections via the command line. Simply install the application, create suitable configuration files containing the connection details, and stunnel takes care of the rest.