H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 304)

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An SSH2.0 server might require the client to pass both password authentication and publickey
authentication (password-publickey authentication) or either of them (any authentication). However, if the
client is running SSH1, the client only needs to pass either authentication, regardless of the requirement
of the server.
The authentication implements in the following steps:
1. The client sends the server an authentication request that includes the username, the authentication
method, and the information related to the authentication method (for example, the password in
the case of password authentication).
2. The server authenticates the client. If the authentication fails, the server sends the client a message
to inform the client of the failure and the methods available for re-authentication.
3. The client selects a method from the list to initiate another authentication.
4. The preceding process repeats until the authentication succeeds, or the number of failed
authentication attempts exceeds the maximum of authentication attempts. In the latter case, the
server tears the session down.
NOTE:
Only clients that runs SSH2.0 or a later version support password re-authentication that the SSH server
initiates.
Session request
After passing authentication, the client sends a session request to the server, and the server listens to and
processes the request from the client. If the server successfully processes the request, the server sends an
SSH_SMSG_SUCCESS packet to the client and goes on to the interaction stage with the client. Otherwise,
the server sends an SSH_SMSG_FAILURE packet to the client to indicate that the processing has failed or
it cannot resolve the request.
Interaction
In this stage, the server and the client exchanges data as follows:
1. The client encrypts and sends the command to be executed to the server.
2. The server decrypts and executes the command, and then encrypts and sends the result to the
client.
3. The client decrypts and displays the result on the terminal.
In this stage, you can paste commands in text format and execute them at the CLI. The text pasted at one
time must be no more than 2000 bytes. H3C recommends you to paste commands in the same view.
Otherwise, the server might not be able to execute the commands correctly.
To execute more than 2000 bytes of command text, save the commands in a configuration file, upload
it to the server through SFTP, and use it to restart the server.