Fundamentals; The Address Book; Overview; Ip Addresses - D-Link DFL-1660 User Manual

Chapter 3. Fundamentals
This chapter describes the fundamental logical objects which make up a NetDefendOS
configuration. These objects include such items as IP addresses and IP rules. Some exist by default
and some must be defined by the administrator.
In addition, the chapter explains the different interface types and explains how security policies are
constructed the administrator.
• The Address Book, page 73
• Services, page 78
• Interfaces, page 84
• ARP, page 99
• The IP Rule Set, page 106
• Schedules, page 112
• Certificates, page 114
• Date and Time, page 118
• DNS, page 125

3.1. The Address Book

3.1.1. Overview

The Address Book contains named objects representing various types of addresses, including IP
addresses, networks and Ethernet MAC addresses.
Using Address Book objects has three distinct benefits; it increases readability, reduces the danger
of entering incorrect network addresses, and makes it easier to change addresses. By using objects
instead of numerical addresses, you only need to make changes in a single location, rather than in
each configuration section where the address appears.

3.1.2. IP Addresses

IP Address objects are used to define symbolic names for various types of IP addresses. Depending
on how the address is specified, an IP Address object can represent either a host (a single IP
address), a network or a range of IP addresses.
In addition, IP Address objects can be used for specifying the credentials used in user
authentication. For more information about this topic, see Chapter 8, User Authentication.
The following list presents the various types of addresses an IP Address object can hold, along with
what format that is used to represent that specific type:
Host
IP Network
A single host is represented simply by its IP address.
For example: 192.168.0.14.
An IP Network is represented using Classless Inter Domain Routing (CIDR) form.
CIDR uses a forward slash and a digit (0-32) to denote the size of the network as a
postfix. This is also known as the netmask.
/24 corresponds to a class C net with 256 addresses (netmask 255.255.255.0), /27
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