Cisco Systems Dial NMS User Manual

Basic Dial NMS Implementation Guide

Task 6Managing IP Addresses by Using DNS

About Managing IP Addresses

Managing IP addresses is a primary network administration function. Assigning and removing
IP addresses can be tedious and error prone. Regardless—you must manage IP addresses to avoid
duplicate IP subnets and addresses.

Domain Name System (DNS) servers provide two kinds of fundamental lookup services:

Forward lookups—Used for looking up the IP address of a provided device name. This is the most
common kind of lookup performed.

Reverse lookups—Used for looking up a device name of a provided IP address. Administratively,
reverse-lookup zones are important tools used for tracking IP address assignments.

In this case study, the dial engineers at THEnet:

Have received a block of IP addresses from the NOC with DNS administrative rights and
instructions for setting up IP address space.

Track IP address assignments by using DNS reverse lookup zones within the existing DNS service.

Use the application Cisco Network Registrar (CNR) and its CLI to manage the IP address database.
CNR is a full-featured IP address management solution for both enterprise and service provider
networks. It includes advanced DNS and Dynamic Host Configuration Protocol (DHCP) servers.

Note

This section assumes you are familiar with the basics of DNS. For more information about
DNS, see DNS and Bind, Third Edition, by Paul Albitz and Cricket Liu. The ISBN number
is 1565925122.

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