ZyXEL Communications GS1920v2 Series User Manual page 360

Figure 261 How SSH Works
Host Identification
1
The SSH client sends a connection request to the SSH server. The server identifies itself with a host key. The
client encrypts a randomly generated session key with the host key and server key and sends the result
back to the server.
The client automatically saves any new server public keys. In subsequent connections, the server public
key is checked against the saved version on the client computer.
Encryption Method
2
Once the identification is verified, both the client and server must agree on the type of encryption
method to use.
Authentication and Data Transmission
3
After the identification is verified and data encryption activated, a secure tunnel is established between
the client and the server. The client then sends its authentication information (user name and password)
to the server to log in to the server.
57.5.1.2 SSH Implementation on the Switch
Your Switch supports SSH version 2 using RSA authentication and three encryption methods (DES, 3DES
and Blowfish). The SSH server is implemented on the Switch for remote management and file transfer on
port 22. Only one SSH connection is allowed at a time.
Chapter 57 Access Control
GS1920v2 Series User's Guide
360