Reference Guide for the Model RT328 and Model RH348 ISDN Routers

Regardless of your particular situation, do not create an arbitrary IP address; always follow the guidelines explained here. For more information about address assignment, refer to RFC 1597,

Address Allocation for Private Internets,

and RFC 1466, Guidelines for Management of IP

Address Space

.

 

Single IP Address Operation Using NAT

If multiple stations on a LAN need to access the Internet simultaneously, they usually have to obtain a range of IP addresses from the ISP. This type of Internet account is much more costly than a single-address account typically used by a single user with a terminal adapter rather than a router. The Model RT328/RH348 router employs a method called extended NAT. This method

allows an entire department of networked PCs to share an Internet account using only a single IP address, which may be statically or dynamically assigned by your Internet service provider (ISP).

The router accomplishes this address sharing by translating the internal LAN IP addresses to a single address that is globally unique on the Internet. The internal LAN IP addresses can be either private addresses or registered addresses. For more information about IP address translation, refer

to RFC 1631, The IP Network Address Translator (NAT)

.

Figure 1-3 illustrates a single IP address operation.

Private IP addresses assigned by user

IP addresses assigned by ISP

192.168.0.2

192.168.0.3

192.168.0.1172.21.15.105

Internet

192.168.0.4

192.168.0.5

7786EA

Figure 1-3. Single IP Address Operation Using NAT

Introduction

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