3Com Switch 8800 Configuration Guide Chapter 50 SSH Terminal Service50-3z The server initiates a procedure to authenticate the user. If the server is configurednot to authenticate the user, the process proceeds to session request phasedirectly.z The client employs an authentication mode to authenticate the server till theauthentication succeeds or the server tears down the connection because oftimeout.Note:SSH provides two authentication modes: password authentication and RSAauthentication.1) Password authentication procedure:z The client sends the username and password to the server;z The server compares the username and password sent from the client with the localconfiguration. If it finds an exact match, the authentication succeeds.2) RSA authentication procedure:z The server configures an RSA public key for the client;z The client sends its RSA public key member module to the server;z The server performs validity authentication on the member module. If theauthentication succeeds, the server generates a random number, encrypts it usingthe RSA public key from the client, and sends the encrypted information back to theclient;z Both the server and the client uses the random number and the session ID with thelength of 16 characters as parameters to calculate the authentication data;z The client sends the authentication data it generates to the server;z The server compares the authentication data from the client with that locallycalculated. If they match, the authentication succeeds.4) Session request: If the authentication succeeds, the client sends a sessionrequest to the server. When the server has successfully processed the request,SSH enters the interactive session phase.5) Interactive session: The client and the server exchange data till the session isover.50.1.2 SSH Server ConfigurationThe following table describes the SSH server configuration tasks.Table 50-1 SSH2.0 Configuration tasksNum Item Command Description1 Entering system view system-view –
