Nortel BayStack 820, Installation And Reference Manual

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Installation and Reference for the BayStack 820 ISDN Router
1-10
206901-A
Network Address Translation
Network Address Translation (NAT) is a powerful and economical way to
allowing Internet access to public servers on your network (for example, an e-mail
server, an FTP server, or a Web server) without applying for or configuring public
IP addresses. NAT not only provides the benefits and administrative simplicity of
a using a single IP address ISP account, it provides the flexibility of a
configurable combination of secure, privately-addressed workstations and port
mapped publicly-accessible applications.
Figure 1-7 illustrates how the router supports NAT.
Figure 1-7. Network Address Translation Support
Security Features
The BayStack 820 ISDN Router provides several security features to help make
your network and data secure:
• Point-to-Point Protocol (PPP) and Password Authentication Protocol/
Challenge Handshake Authentication Protocol (PAP/CHAP) authentication
for all dial-in users and LAN-to-LAN communications
• Callback to confirm the identification of dial-in remote users
• ISDN Caller ID for incoming call authentication
LAN Interface
Public IP address Private IP address
Private
workstations on
Public computers
on your public
LAN
ISDN Interface
(IP address usually assigned by ISP)
Internet
your LAN