1-11 SSH ConfigurationWhen configuring SSH, go to these sections for information you are interested:z SSH Overviewz SSH Server and Clientz Displaying and Maintaining SSH Configurationz Comparison of SSH Commands with the Same Functionsz SSH Configuration ExamplesSSH OverviewIntroduction to SSHSecure Shell (SSH) is a protocol that provides secure remote login and other security services ininsecure network environments, allowing for secure access to the Command Line Interface (CLI) of aswitch for configuration and management. In an SSH connection, data are encrypted before being sentout and decrypted after they reach the destination. This prevents attacks such as plain text passwordinterception. SSH also provides powerful user authentication functions that prevent attacks such asDNS and IP spoofing. Besides, SSH can also provide data compression to increase transmission speed,take the place of Telnet and provide a secure “channel” for transfers using File Transfer Protocol (FTP).SSH adopts the client-server model. The switch can be configured as an SSH client, an SSH server, orboth at the same time. As an SSH server, the switch provides secure connections to multiple clients. Asan SSH client, the switch allows the remote server to establish a secure SSH connection for remotelogin.Algorithm and KeyAlgorithm is a set of transformation rules for encryption and decryption. Information without beingencrypted is known as plain text, while information that is encrypted is known as cipher text. Encryptionand decryption are performed using a string of characters called a key, which controls thetransformation between plain text and cipher text, for example, changing the plain text into cipher text orcipher text into plain text.Figure 1-1 Encryption and decryptionThere are two types of key algorithms:z Symmetric key algorithm
