DNS (Donain Name System)
|What is DNS Server
DNS is a name resolution of converting computer name to IP address.DNS name resolution helps to identify the service location on the basic of name records.The primary DNS server provides read and write services to manually inscribe the name record.
Introduction of DNS:-
1 HOST NAME
2 FQDN ( Fully Qualified Domain Name)
Why we use DNS— User identify onle user friendly name and all computer and technology identfy IP address and MAC address . We can use DNS to solve this problem because DNS is convert Host name, FQDN to IP address.We can name resolution for this process . ok i have a example for you:- think that you can not remember lot of IP address but you can easily remember host name just like google Facebook, yahoo, gmail ,etc.But computer identfy only IP address, so we need DNS . I this You understand why we need DNS.
Now we know about parts of DNS
HOST NAME FQDN DOMAIN NAME NAMESPACE DNS SERVER
1 HOST NAME :- Host name is a computer name. host name is also called netbios name (Network Basic Input Output System).we can identify of tha computer but we can not identify location of the computer.if we can use ip address then we can identify location and network both with the help oh net id. (But we can identify computer with host name on only small network but we can not identify it on large network )
You laso read : what is the IP address
2. FQDN :-Fully Qualified Domain Name -this is a unique name of the computer.We can identify host id and location of computer.
3.Domain Namespace :- Donain Namespace is enable user to easilylocate the network service and resource . The domain namespace include the root domain, the top level domain and second level domain of the organization and organize domain in hierachy tree structure.
4.DNS server :- Any provider is provide domain name service is a domain server. DNS server is convert HOST NAME (FQDN) to IP address and IP address To Host name. there are many component of DNS server –
(a) DNS Query :- When DNS is a request for name resolution, that is send to DNS server by the client in a network A client can send query to DNS server or DNS server also send a DNS query to other DNS server.
There are two types of DNS Query
1. Interative Query :- It is a query in which the client accept the best available answer from the DNS server. In case of server dose not know the answer it may direct forward this query another DNS server.
2:- Recursive Query:- IN this query DNS server didn’t take responsibility to give best answer to client. DNS server did not forward this query to another DNS server .
(b) DNS server Cache:- It is a temporary Storage area in DNS server that store the most frequently or recently access record. this cache is clear when DNS server is stopped.
(c) DNS Zone :- Is is a part of DNS data base that contain record of domain or multiple domain.This zone also contain is a list of host name to IP Address .
FORWARD LOOKUP ZONE – it covert FQDN into IP address
Reverse LOOKUP ZONE – it convert IP address to FQDN
Types of zone
1. Primary Zone :- All Domain record are created in it. this is the first zone in network.
2 Secondary Zone :-It ia s Zone that contain a read only copy of the DNS record that are store in the primary zone .
3. Active Directory Integrated Zone :- This zone is created automatically when we install and configure active directory.