SSH stands for Secure Shell. Developed by SSH Communications Security, Inc., SSH is a method of communicating with another computer. Data sent via a SSH connection is encrypted, meaning that any information intercepted by a third party would be scrambled and unreadable.
Several tasks can be executed using an SSH connection. These include remotely logging into a computer that is a part of a network, transferring files from one computer to another, and executing commands on a remote machine. SSH is considered more secure than other methods, including telnet, rlogin, rcp, rdist and rsh. SSH protects a network from several types of attacks, such as DNS spoofing, IP spoofing and IP source routing. When an attacker takes over the network, the only risk is disconnection, versus hijacking the connection or playing back the traffic.
It is possible to secure the entire session with SSH if the login process includes SSH encryption. Unlike rlogin, SSH protects the security of the password. SSH is based on a Linux shell, which interprets commands from a user. Unix commands are used to perform basic executions, such as transferring files from a remote computer as well as viewing and modifying those files. The Unix commands are either entered manually or sent from a program with a graphical user interface.