SSH (Secure Shell) is an open source network protocol that is used to connect local or remote Linux servers to transfer files, make remote backups, remote command execution and other network related tasks via scp or sftp between two servers that connects on secure channel over the network.
In this article, I will show you some simple tools and tricks that will help you to tighten your ssh server security. Here you will find some useful information on how to secure and prevent ssh server from brute force and dictionary attacks.
SOURCE: tecmint.com