The Domain Name System (DNS) helps users to find their way around the Internet. Every computer on the Internet has a unique address just like a telephone number which is a rather complicated string of numbers. It is called its "IP address" (IP stands for "Internet Protocol").

But it is hard to remember everyone's IP address. The DNS makes it easier by allowing a familiar string of letters (the "domain name") to be used instead of the arcane IP address. So instead of typing 192.0.34.65, you can type www.icann.org. It is a "mnemonic" device that makes addresses easier to remember.

Translating the name into the IP address is called "resolving the domain name." The goal of the DNS is for any Internet user any place in the world to reach a specific website IP address by entering its domain name. Domain names are also used for reaching e-mail addresses and for other Internet applications.

ICANN is the global, non-profit, private-sector coordinating body acting in the public interest, which is responsible for managing and coordinating the DNS to ensure universal resolvability.. ICANN ensures that the DNS continues to function effectively – by overseeing the distribution of unique numeric IP addresses and domain names. Among its other responsibilities, ICANN oversees the processes and systems that ensure that each domain name maps to the correct IP address.

The reference DNS server software is BIND. Most production Internet name servers are based on BIND running on some form of Unix (including Linux and MacOS X). Microsoft's DNS server for Windows XP/2000/NT is popular in Microsoft environments. Other significant options are the various ports of BIND to Windows, and several non-BIND servers for Unix, MacOS and VMS.

The grand-daddy of all DNS server systems, BIND stands for Berkeley Internet Name Domain and is regarded as the reference implementation of a DNS server. It usually serves as the base for experimentation with DNS protocol extensions. BIND is free and has been ported to many operating systems. Most BIND servers run on some variant of Unix or Linux, although BIND on Windows is also available.

Because of its long development history and its support for most of the DNS standards, BIND is generally preferred for large production name servers on the Internet. At the other end of the scale, BIND can also run well on an ancient PC with as little as 32MB RAM, and this can be a low-cost name server platform for a smaller site on a budget.

One more note-worthy comment about BIND is that a version has been ported for even non-mainstream OSs such as Mac 9 & older, VMS , OS2 , Netware etc.

Visit the BIND website for more info, patches & updates at www.isc.org/bind.html

Named after its developer D.J.Bernstein who also authored the Qmail - Mail server system. The main features of djbDNS are that the two main name server functions of caching and acting as an authoritative server are sensibly split into two separate programs [dnscache and tinydns]. Increasing system stability & speed.

One more interesting feature is the $500 security guarantee / challenge by the author , who offers $500 for any one security holes / flaws in the latest version of the software.

djbDNS is priced free, with some restrictions on redistribution & modifications.

Visit the djbDNS website for more info at http://cr.yp.to/djbdns.html

This is a commercial DNS server product from a company called Nominum whose Chief Scientist, Paul Mockapetris, invented DNS in 1983. Today Nominum delivers commercial DNS servers that set the benchmark for scalability, reliability and security.

DNS servers perform two basic functions. The first DNS function is to provide the authoritative IP address information for a network resource. The second is sit between a user and the network as a whole, and locate and cache the address information received from an authoritative server in response to a user query. Nominum created two separate DNS servers optimized for these discrete functions, called Nominum Foundation™ ANS (Authoritative Name Server) and Nominum Foundation™ CNS (Caching Name Server).

Visit the ANS / CNS pages on Nominum's website for more info at www.nominum.com

A Open-source DNS server system , PowerDNS Nameserver is a modern, advanced and high performance authoritative-only nameserver. It is written from scratch and conforms to all relevant DNS standards documents. Furthermore, PowerDNS interfaces with almost any database.

The PowerDNS Nameserver utilizes, a flexible backend architecture can access DNS information from any data source. This includes file formats, Bind zone files, relational databases or LDAP directories.

If you have specific needs for your DNS infrastructure then you can use the Backend Developers Kit to write the 'glue' between PowerDNS and your data or logic.

PowerDNS is by default configured to serve all information directly from a database, which results in unmatched maintainability of your DNS information.


Visit the PowerDNS website for more info at www.powerDNS.org

NSD is a new entrant in the DNS server space. It is a open-source project with the development hosted by a Netherlands based company called NLnet Labs. NSD is an authoritative only, high performance, simple name server and the current stable version is NSD 2.1.5.

NLnet Labs was founded on first of January 2000 by foundation NLnet. It started with a team of two employees working on the DNSSEC project.

NLnet Labs has a long term commitment for supporting NSD. There will be an advanced notice when their commitment ends. The latest NSD release will supported for at least two years.

Visit the NSD website for more info at www.nlnetlabs.nl

BIND now officially supports the Windows OS for both BIND 8 and BIND 9. This is a stable and reliable server in a number of production environments, although server administration is command-line based, it is highly recommended as it is a free software and the source code is freely available.

A company called MetaInfo has a commercial port of BIND to Windows called Meta DNS Pro, which is fully functional and well regarded. Its management frontend runs only on Windows, but the server is actually available for Windows, Linux or Solaris, as one would expect of a BIND-based product. Meta DNS Pro includes the tools to find, analyze, and manage the data in a small business's name space or an external name space.

The MetaDNS system features :

• BIND-based DNS services
• Initialization Wizard
• DNS Slave Server Wizard
• Zone Template Tool
• Service and Zone Configuration Check
• Effective Data Validation

Visit the MetaDNS website for more info at www.metainfo.com

Windows 2003 edition comes with a built in DNS server that has seen increasing adoption and acceptance since its first release for Windows 2000. It is regarded as stable and is well-integrated with Microsoft's server administration tools.

The first stable versions of Microsoft's DNS server component was seen in the NT Server 4.0 version , although there were mixed feelings about its suitability for robust, large-scale service. It was found to be vulnerable to a variety of denial-of-service attacks. It required a continous series of hot-fixes, patches and service packs to keep this software in running condition.

Visit the Microsoft website for further info about the MicrosoftDNS server

With Simple DNS Plus you can host your own domain name, or simply speed up Internet access by running your own DNS server.

Simple DNS Plus can easily be integrated with your web-site for ISP customer signup etc., or even a full web-based DNS solution. Simple DNS Plus is also a DHCP server, it comes with a DNS Look Up tool, and many other features.

Log into this website for the latest info about Simple DNS system. The long list of features and options are noted in this page : Features

Visit the Simple DNS server's website for more info at www.simpledns.com

QuickDNS Small Business from 'Men & Mice' is the ideal DNS management application for businesses with 500 IP addresses or less. It enables professional DNS management with little effort and requires minimum know-how.

QuickDNS allows you to professionally manage DNS servers on different platforms through an easy-to-use interface. In the past, you had to be an expert in order to set up and maintain DNS professionally. Now with QuickDNS, you can set up your DNS like any other application. It provides fast, easy installation on top of your current DNS and automates tedious DNS tasks, such as creating reverse (PTR) records. It even provides wizards for common tasks such as mail server setup or zone creation. With the remote management feature you can manage your DNS from anywhere at any time.

Apart from the Mac OS , the QuickDNS system is available for the Windows & Linux platforms as well.

Visit the QuickDNS pages on Men & Mice's website for more info at www.menandmice.com

Mac OS X and Mac OS X Server has a DNS serving software called StellarDNS included in the installation. The typical way to configure and start up DNS is via the command line terminal. StellarDNS simplifies the process by giving you a clean interface for setting up the service as well as starting and stopping it.

StellarDNS allows you to edit the configuration files associated with DNS without knowing complicated syntax constructs or resorting to command-line tools.

Stellar uses the same Berkeley Internet Name Domain implementation of the DNS protocols used by the majority of name servers on the Internet. It provides a robust and stable architecture upon which to build your organization's naming architecture.

Visit the StellarDNS pages on Apple's website for more info at www.apple.com