Knowledgebase: cPanel Web Hosting
How do domain names and DNS work?
Posted by Help Desk (6), Last modified by NOC Desk Monitors on 07 August 2018 12:28 PM
Computers on the Internet use IP (Internet Protocol) Addresses to talk to one another, because humans find words much easier to remember than numbers, domain names were invented to make it easier for people to remember and access various computers connected to the internet.
 
This is where DNS or the Domain Name System comes in to play and is an integral part of the Internet. It refers to a system of servers and databases on the Internet that are responsible for translating a Domain Name into an IP Address.
 
Say you wanted to look at our website. You would type www.hostnetworks.com.au in your browser. The DNS will translate this to the IP Address of our site (202.174.100.100).
 
The DNS works in a similar way to directory assistance. You ask directory assistance for the phone number of Host Networks and they will search for it and reutrn with the number or connect you.
 
The DNS works in the following way.
  • You enter www.hostnetworks.com.au in your browser.
  • Your browser will then check with either your temporary cached DNS answers stored on your computer (held for around 24 hours or until you reboot your computer). If not known it will then ask your ISP's DNS. Your ISP also caches answers to reduce having to look up the information again.
  • If your ISP does not know the answer, it will then ask around to find what name server holds the records for the IP Address.
  • It then finds the answer and sees that ns1.hostnetworks.com.au (one of our name servers) can resolve the Domain Name to the IP Address and the servers can then talk to one another.
This is where some problems can occur. Cached answers (temporary stored information) may not know the correct information as the information may be stale. For example, if you visited www.acmeco.com.au and they then changed their IP address, and you went back to the site later that day, you may no longer see the site as the old IP Address could be stored on your computer or at your ISP because either you or another person using the same ISP visited that site earlier and the ISP has stored that information in their cache.
 
When this happens most people think the site is down. However if they flush their computers temporary DNS cache or their ISP has reached their time out settings for storing DNS answers the site will show again as they then have gone out and retrieved the new information.
 
It is similar to you calling Directory Assistance, getting the number and writing it down, later you go to call that number and it is no longer connected as they had changed numbers. You then call Directory Assistance again to get the new number.
 
 
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