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Wireless IAD User Manual
NAT (Network Address Translation) IP Address
NAT is an Internet standard that translates a private IP within one network to
a public IP address, either a static or dynamic one. NAT provides a type of
firewall by hiding internal IP addresses. It also enables a company to use
more internal IP addresses.
If the IP addresses given by your ISP are not enough for each PC on the
LAN and the ADSL Router, you need to use NAT. With NAT, you make up a
private IP network for the LAN and assign an IP address from that network
to each PC. One of some public addresses is configured and mapped to a
private workstation address when accesses are made through the gateway
to a public network.
For example, the ADSL Router is assigned with the public IP address of
168.111.2.1. With NAT enabled, it creates a Virtual LAN. Each PC on the
Virtual LAN is assigned with a private IP address with default value of
192.168.2.2 to 192.168.2.254. These PCs are not accessible by the outside
world but they can communicate with the outside world through the public
IP 168.111.2.1.
Private IP Address
Private IP addresses are also LAN IP addresses, but are considered "illegal"
IP addresses to the Internet. They are private to an enterprise while still
permitting full network layer connectivity between all hosts inside an
enterprise as well as all public hosts of different enterprises.
The ADSL Router uses private IP addresses by assigning them to the LAN
that cannot be directly accessed by the Internet or remote server. To access
the Internet, private network should have an agent to translate the private IP
address to public IP address.
Public IP Address
Public IP addresses are LAN IP addresses that can be considered "legal"
for the Internet, because they can be recognized and accessed by any
device on the other side of the DSL connection. In most cases they are
allocated by your ISP.
If you are given a range of fixed IP addresses, then one can be assigned to
the router and the others to network devices on the LAN, such as computer
workstations, ftp servers, and web servers.
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