DNS

Acronym. Domain Name Server.

A server which translates a Domain Name into one or more IP Addresses.

When using a Web Browser, DNS takes the part between "http://" and the first slash "/" and converts it into an IP Address, which is a very large number which uniquely identifies a web server on the internet.

For example for the web address:

http://www.example.com/

DNS takes the term www.example.com and converts it into an IP address: 192.0.32.10

DNS Applications

DNS is used as the primary way of converting names on the internet to addresses. Any application which accesses the internet uses DNS first to find a server. Because DNS is the first step used in any internet transaction, it is the target of security breaks. |

DNS is used by the following applications:

Web Browser
- To resolve the host portion of a URL, and any additional URL on a page.
Email Program
- To resolve your email server's IP Address, and to determine the Mail Exchanger for outbound email.
- Recently, to retrieve a DomainKeys record to authenticate a sender of an email
FTP Program
- To resolve the host name of a remote FTP server
Operating System
- To resolve the name of your vendor's servers for Software Update ... (Mac OS X), or Windows Update ... (Windows)
Any application which checks for software updates
- To resolve the name of the vendor's host server

DNS Tools

On Linux, FreeBSD, Mac OS X, or any variant, you can use a command line tool (using iTerm, Terminal, xterm, or some similar shell tool) to perform DNS on the fly using the host command:

> host www.example.com
www.example.com has address 192.0.32.10

On Windows, to perform DNS requests, go to the Start Menu, then Run ..., and type in nslookup:

Default Server: acumen
Address: 192.168.0.1

> www.example.com
Server: acumen
Address: 192.168.0.1

Non-authoritative answer:
Name: www.example.com
Address: 192.0.32.10

You can just enter the name you wish to resolve and it will output the response from your local DNS server.

More info

Also known as Name Server or one word: Nameserver
See Name Server on Wikipedia