Technical data

SSH Terminal Services 373
which compares it with the local authentication data. If the data match, the
user is allowed to access the switch. Otherwise, the authentication process
fails.
■ Session request: The client sends session request messages to the server
which processes the request messages.
■ Interactive session: Both ends exchange data until the session ends.
Session packets are encrypted in transfer and the session key is generated
randomly. Encryption is used in exchanging session key and RSA authentication
achieves key exchange without transfer over the network. The authentication will
also start even if the username received is not configured at the server so malicious
intruders cannot judge whether a username they key in exists or not. This is also a
way to protect the username.
Configuring the SSH
Server
Basic configuration tasks refer to those required for successful connection
between the SSH client and server. Advanced configuration tasks are those that
modify SSH parameters.
Configuration tasks on the SSH server are described in the following sections:
■ Setting the System Protocol
■ Configuring and Cancelling a Local RSA Key Pair
■ Configuring the Authentication Type
■ Defining the Update Interval of the Server Key
■ Defining the SSH Authentication Timeout Value
■ Defining the SSH Authentication Retry Value
■ Entering the Public Key Edit View and Editing a Public Key
■ Associating a Public Key with an SSH User
Setting the System Protocol
By default, the system only supports the Telnet protocol, so you must specify the
SSH protocol for the system before enabling SSH.
Perform the following configuration in system view.
CAUTION: If the SSH protocol is specified, to ensure a successful login, you must
configure the AAA authentication using the authentication-mode scheme
command. The
protocol inbound ssh configuration fails if you configure
authentication-mode password and authentication-mode none. When you
configure the SSH protocol successfully for the user interface, then you cannot
configure
authentication-mode password and authentication-mode none any
more.
Table 80 Setting the System Protocol
Operation Command
Set system protocol and link maximum protocol inbound { all | ssh | telnet }