Secure Shell (SSH) Feature Overview and Configuration Guide
Secure management is important in modern networks, as the ability to easily and effectively manage switches and routers, and the requirement for security, are two almost universal requirements.
Protocols such as Telnet and rlogin allow you to manage devices remotely, but can have serious security problems, such as relying on reusable plain text passwords that are vulnerable to wiretapping or password guessing. The Secure Shell protocol is superior to these protocols by providing encrypted and strongly authenticated remote login sessions.