Netopia 2200 - Manual (Page 340)

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from routers on networks connected to its WAN inter face. In other words, the end com-
puter stations on your LAN are
invisible from the Internet.
Only a single WAN IP address is required to provide this security support for your entire
LAN.
LAN sites that communicate through an Internet Ser vice Provider typically enable NAT,
since they usually purchase only one IP address from the ISP.
• When NAT is ON, the Netopia Gateway “proxies” for the end computer stations on your
network by pretending to be the originating host for network communications from non-
originating networks. The WAN inter face address is the only IP address exposed.
The Netopia Gateway tracks which local hosts are communicating with which remote
hosts. It routes packets received from remote networks to the correct computer on the
LAN (Ethernet) inter face.
• When NAT is OFF, a Netopia Gateway acts as a traditional TCP/IP router, all LAN com-
puters/devices are exposed to the Internet.
A diagram of a typical NAT-enabled LAN follows:
WAN
Interface
LAN
Ethernet
Interface
Netopia Gateway
NAT
Internet
Embedded Admin Services:
HTTP-Web Server and Telnet Server Port
NAT-protected
LAN stations
Ethernet