User`s guide

ZyWALL IDP 10 User’s Guide
Chapter 5 Remote Management 48
5.4.2 SSH Implementation on the ZyWALL
Your ZyWALL supports SSH version 1.5 using RSA authentication and three encryption
methods (DES, 3DES and Blowfish). The SSH server is implemented on the ZyWALL for
remote management and file transfer on port 22. Only one SSH connection is allowed at a
time.
5.4.3 Requirements for Using SSH
You must install an SSH client program on a client computer (Windows or Linux operating
system) that is used to connect to the ZyWALL over SSH.
5.5 SSH (Secure SHell) Configuration
To change your ZyWALL’s Secure Shell settings, click REMOTE MGNT, then the SSH tab.
Figure 21 How SSH Works
1. 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.
2. Encryption Method
Once the identification is verified, both the client
and server must agree on the type of encryption
method to use.
3. Authentication and Data Transmission
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.