ZyXEL Communications 1000 ユーザーズマニュアル

 Chapter 50 System

ZyWALL USG 1000 User’s Guide

SSH is a secure communication protocol that combines authentication and data 
encryption to provide secure encrypted communication between two hosts over an 
unsecured network. In the following figure, computer A on the Internet uses SSH 
to securely connect to the WAN port of the ZyWALL for a management session.

Figure 540   SSH Communication Over the WAN Example

The following figure is an example of how a secure connection is established 
between two remote hosts using SSH v1.

Figure 541   How SSH v1 Works Example

Host Identification

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.