Domain Name System (DNS) Server Details
The DNS Server: The DNS server (also known as name server) is usually
provided by the web hosting company such as Netsouth. The DNS server has entries
of the domain name as explained next. At least a primary (e.g. ns1.nameserver.net)
and a secondary (e.g. ns2.nameserver.net) name server addresses are required.
DNS server setup for Netsouth clients is done using the Netsouth name servers.
How a Domain Server Works : Before understanding how to configure a
domain name, one should know how a domain name works. There are three parts to
setting up a domain name for a Website - (1) registering the domain name with
a domain registrar, (2) setting up the domain name entry in a DNS server, and
finally (3) configuring the web server to listen to the requests for the domain
name. A request for the domain (e.g. http://ncsnet.com) starts at one of the
registrar's server, which then routes it to a DNS server containing the DNS
information for the domain. Once the DNS record for the domain resolves the
domain name to a particular IP address, the request is sent to the web server
listening to that IP address. The web server can now delegate the request to the
particular Website based on the domain name in the host header of the request
object.
Domain Setup On DNS Server: The
domain setup on the DNS server can be done after the domain is registered.
However, the domain name will not work until the DNS setup is completed. A DNS
server maps a domain name to IP address(es) of the web server and mail server so
that a client can connect to the webserver or mail server using the domain name
and not the IP address. A forward lookup zone is created for the domain name in
the DNS server. Start of authority (SOA), Name server (NS), Hostname (A), Canonical
Names (CNAME) and Mail eXchange (MX) entries are added to the forward lookup zone.
Domain Name System (DNS) Definition:
DNS is an Internet Engineering Task Force (IETF) standard name service that allows
your computer to register and resolve domain names. The DNS makes it possible to
assign domain names to organizations independent of the routing of the numerical
IP address. In other words, DNS is a system that translates domain names into IP
addresses. This is necessary because computers only make use of IP addresses yet we
use only human readable names since the names are easier to remember than IP
addresses. Without this DNS resolution, the internet would be a very inconvenient
place. DNS resolution is therefore a very important task. However, you may sometimes
try to connect to a system by name and get a DNS error because the name did not
resolve to the proper IP address
There can be several causes for name not
resolving, such as:
•• The DNS server is down.
•• IP connectivity gets lost
and thus the DNS cannot resolve.
•• DNS cache poisoning.
•• Update and zone issues.
•• The DNS server does not
have network connectivity to the root servers.
There are a number of ways to find out whether your system is resolving properly.
You can use nslookup to verify name resolution. The nslookup command can be used
to find various details relating to a particular DNS (Domain Name System) such as
IP address, MX records etc.
