Your Default Nat Setup; Table 8-1 Napt Rule - ZyXEL Communications Prestige 623 series User Manual

Prestige 623 Series Dual-link ADSL Router
NAT rules such as these provide several benefits:
•
They eliminate the need for purchasing multiple public IP addresses for computers on your LAN.
You can make up your own private IP addresses at no cost. These addresses are not useful on the
Internet, however.
•
They provide a measure of security for your LAN by enabling you to assign private IP addresses.
The Prestige prevents external access to your privately addressed computers (except when using an
rdr rule discussed later). In addition, the private addresses are replaced in all outbound data
packets, so external computers never see the private addresses anyway.
The type of NAT function described above is called network address port translation (napt). You can use
other types, called flavors, of NAT for other purposes; for example, providing outside access to your LAN
or translating multiple private addresses to multiple public addresses.
8.2

Your Default NAT Setup

By default, NAT is enabled, with an napt rule configured to perform the following translation:
This default NAT setup assumes that, on each LAN computer, you configured TCP/IP properties as
follows:
•
You selected the check box that enables them to receive their IP addresses automatically (that is, to
use a DHCP server);
or,
•
You assigned static IP addresses to your computers in the range 192.168.1.3 through 192.168.1.34.
If your computers are not configured in one of these ways, you can either change the IP addresses on your
computers to match the NAT setup, or delete this NAT rule and add a new one that matches the addresses
you assigned to your computers (see Adding NAT Rules section).
8-2

Table 8-1 NAPT Rule

THESE PRIVATE IP
ADDRESSES:
192.168.1.3
192.168.1.4
.
.
.
192.168.1.34
...ARE TRANSLATED TO:
Your ISP-assigned
public IP address
Configuring Network Address Translation