Once you have a valid SSL certificate installed on your server, whether self-signed or generated by a recognized signing authority, you are in a position to secure the mongod server instance. If you are using self-signed certificates, please be aware that although communications to and from the server are encrypted, no identity validation takes place. This means the communications chain can potentially be subject to man-in-the-middle attacks.
Before you begin, please consider that if your database operates behind a firewall, and all of your mongod server instances communicate solely inside the company Local Area Network (LAN), implementing TLS/SSL secure communications might introduce unnecessary performance degradation. By their very nature, TLS/SSL communications are slower as an extra handshake is needed to initiate the connection, and a cumbersome encryption/decryption process must take place for each communication.
No matter what operating system is...