Address Translation; Overview - D-Link DFL-1660 User Manual

Chapter 7. Address Translation
This chapter describes NetDefendOS address translation capabilities.
• Overview, page 369
• NAT, page 370
• NAT Pools, page 375
• SAT, page 378

7.1. Overview

The ability of NetDefendOS to change the IP address of packets as they pass through the NetDefend
Firewall is known as address translation.
The ability to transform one IP address to another can have many benefits. Two of the most
important are:
• Private IPv4 addresses can be used on a protected network where protected hosts need to have
access to the public Internet. There may also be servers with private IPv4 addresses that need to
be accessible from the public Internet.
• Security is increased by making it more difficult for intruders to understand the topology of the
protected network. Address translation hides internal IP addresses which means that an attack
coming from the "outside" is more difficult.
Types of Translation
NetDefendOS supports two types of translation:
• Dynamic Network Address Translation (NAT)
• Static Address Translation (SAT)
Application of both types of translation depend on the specified security policies, which means that
they are applied to specific traffic based on filtering rules that define combinations of
source/destination network/interface as well as service. Two types of NetDefendOS IP rules, NAT
rules and SAT rules are used to configure address translation.
This section describes and provides examples of configuring NAT and SAT rules.
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