How Ssh Works - ZyXEL Communications NWA3000-N User Manual

following figure, computer B on the Internet uses SSH to securely connect to the WAN port of the
device (A) for a management session.
Figure 89 SSH Communication Over the WAN Example

15.6.1 How SSH Works

The following figure is an example of how a secure connection is established between two remote
hosts using SSH v1.
Figure 90 How SSH v1 Works Example
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.
NWA3000-N Series User's Guide
Chapter 15 System
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