Fundamentals; The Address Book; Overview; Ip Addresses - D-Link NetDefend DFL-210 User Manual

Chapter 3. Fundamentals
This chapter describes the fundamental logical objects upon which NetDefendOS is built. These lo-
gical objects include such things as addresses, services and schedules. In addition, this chapter ex-
plains how the various supported interfaces work, it outlines how policies are constructed and how
basic system settings are configured.
• The Address Book, page 31
• Services, page 35
• Interfaces, page 40
• ARP, page 47
• The IP Rule-Set, page 52
• Schedules, page 55
• X.509 Certificates, page 57
• Setting Date and Time, page 59
• DNS Lookup, page 64

3.1. The Address Book

3.1.1. Overview

The Address Book contains named objects representing various types of addresses, including IP ad-
dresses, 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 ad-
dress), a network, a range of IP addresses or even a DNS name.
In addition, IP Address objects can be used for specifying user credentials later used by the various
user authentication subsystems. For more information on this, 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 CIDR (Classless Inter Domain Routing) form.
CIDR uses a forward slash and a digit (0-32) to denote the size of the network
(netmask). /24 corresponds to a class C net with 256 addresses (netmask
255.255.255.0), /27 corresponds to a 32 address net (netmask 255.255.255.224)
and so forth. The numbers 0-32 correspond to the number of binary ones in the
netmask.
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