Absolute Beginner's Guide to Networking by Joseph W. Habraken

Author:Joseph W. Habraken [Habraken, Joseph W.]
Language: eng
Format: epub
Tags: Electronic Books, Computer Networks, Computers, Networking, General
ISBN: 9780789729118
Google: piV-KVIXcjUC
Amazon: 0789729113
Barnesnoble: 0789729113
Publisher: Que
Published: 2001-01-02T08:00:00+00:00

Understanding DNS

An extremely important part of managing IP networks is understanding the Domain Name Service. The Domain Name System (DNS) provides a hierarchical name resolution strategy for resolving a Fully Qualified Domain Name (FQDN) to an IP address. DNS servers provide this "friendly name" to logical address (the IP address) resolution on TCP/IP networks such as the Internet. For example, when you type Microsoft.com into your Web browser address window, a DNS server somewhere on the Internet actually resolves the FQDN (Microsoft.com) to the IP address of the Microsoft Web site.

So in terms of TCP/IP networks and the Internet in particular, each organization will deploy DNS servers that provide FQDN resolution to IP addresses. In effect, each large company, organization, or service provider manages the name resolution duties for their own portion of the Internet. In fact, when a company registers a domain name with InterNIC, the company must provide the IP addresses of two internal DNS servers that will handle the name resolution duties for that domain (for individuals that register a domain name, the DNS server addresses are typically provided by your service provider).

Servers maintained by InterNIC provide the mechanism for a local DNS server to resolve a FQDN to an IP address on a remote portion of the Internet. Since the InterNIC servers hold a database that provides a listing of all domain DNS servers and their IP addresses, the local DNS merely queries the InterNIC server for the IP address of the DNS server that services a particular domain (using the friendly name). Once the local server receives the IP address of the remote DNS server, it can then query it directly for the resolution of the remote FQDN to an IP address.

With each network really responsible for the local mapping of friendly names to IP addresses using DNS servers, the DNS database is a distributed database. Each organization maintains its part of the overall DNS database. This means that each organization will typically deploy its own DNS servers (which handle most of the local DNS related queries). We will discuss deploying a DNS server in a moment. First, we need to take a look at the DNS namespace.

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