How DNS Works

The Domain Name System, otherwise known as DNS, is a key component of the Internet. DNS is the resolution of a domain name to an IP address. For those of you who are not aware of how it works read on to learn the basics.

DNS Lookups

There are two approaches to DNS lookups:

1. The "normal" or forward DNS lookup and;
2. The reverse DNS look up.

Forward DNS Lookups

The forward lookup, or simple DNS lookup, is the most commonly used approach to DNS. The forward approach to DNS is simply finding out the IP address of a domain. People tend to find it difficult to remember long strings of numbers. Instead, it's easier to remember a domain name that uses words. However, electronic devices use streams of 1's and 0's to communicate. The only way for one computer to communicate with another is by uniquely identification. The method identification used on the Internet is by IP addresses.

Here are the simple steps for DNS resolution:

1. A user enters a domain name into their Internet browser. (www.biswashost.com)
2. The computer sends the domain name as a DNS request to the user's Internet Service Provider (ISP).
3. The ISP determines if it has the IP address associated with that name;
4. If not, the ISP forwards the request to other providers in an effort to located the DNS record that contains the data.
5. Once the record is found, the IP address of the domain is returned to the user.
6. Now, the user's computer can communicate directly with the server.

Many people compare DNS to a "phone book", which is an oversimplification of a very complex system. The world wide web provides the fundamental function of inter-connectivity, which is much more than the telephone relays of before.

Reverse DNS Lookup

In a reverse DNS lookup, the steps are the same except that it starts out with an IP address and returns with the domain name. In actual reality this can take a while and when a DNS is unable to find what it needs whether it is a domain name or an IP address, we end up with the screen we all hate that states “this webpage cannot be found”. This is due to the servers being busy or the web browser timing out.