Zyxel OLT2412 [242/326] How ssh works

Chapter 32 Access Control

OLT2412 User’s Guide

242

32.11 How SSH works

The following table summarizes how a secure connection is established between two remote hosts.

Figure 61 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.