ZyXEL Communications NXC8160 User Manual

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Chapter 4 Centralized Configuration
NXC-8160 User’s Guide
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Unlike Telnet or FTP, which transmit data in plaintext (clear or unencrypted text), 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 NXC-8160 
for a management session. 
"
If the NXC-8160 is behind a NAT router or a firewall, you need to configure the 
router or firewall to allow a SSH connection to the NXC-8160.
Figure 11   SSH Communication Over the WAN Example 
4.3  How SSH Works  
The following table summarizes how a secure connection is established between two remote 
hosts. 
Figure 12   How SSH Works