DOMAIN NAME IN DNS

 

 DOMAIN NAME IN DNS

We have seen about DNS server in our previous post.
There you must came across the word "Domain Name".
The purpose of DNS server is to convert domain name into IP address.
The domain name used has various categories. They are

• Generic Domain
• Country Domain
• Inverse Domain

 

Generic Domain

We are using many domain names such as google.com, wikipedia.org, slideshare.net, annauniv.edu, etc.
These sites are categorized by the name after dot in it.
By using the extension these domain names are routed to corresponding servers.
Some of the extension domain names in generic domains are

.com --> commercial organizations
.edu --> educational institutions
.gov --> governmental institutions
.net --> network support centers
.org --> nonprofit organizations
.info --> information service providers

Country Domain

The country domain uses the country name as extension.
The extension should be in two letters.
For example,    google.co.in
Some extensions of countries are

India --> .in
United States --> .us
United Kingdom --> .uk

Inverse Domain

Inverse domain is the used to map address to a name.
Hence the name inverse is used.
For instance, if a server receives a request from a client and this server has only the ip addresses of the clients in its list then the server needs to find out if this client is on its authorized client list.
In order to determine if the client is on the authorized client list, server asks its resolver to query to the DNS server to map an address to name.
And this type of querys are called inverse query.
For example,    121.45.34.132.in.addr.arpa