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How to troubleshoot dns failure

Ever have one of those annoying DNS errors, well, there are many things that could be the culprit. Hopefully this hub will shed some light on DNS, how it works, and how to fix common DNS errors and messages

First of all, what is DNS?

DNS stands for Domain Name System, and in a nutshell it's a way of translating domain names (www.domainname.com) to IP Addresses (192.168.0.1). These systems can be public such as is used by every website and mail server in the world. Or private/internal, often used for intranet websites and other internal system.

IP addresses relating to domain change all the time, if it is for example moving to a new server it will probably be assigned a new IP address. When this change is issues, the change must propagate across the entire internet, it happens with a top-down approach. First the main ROOT DNS servers will be notified of it, and then the change request goes down the line until it's updated on your internet service providers DNS servers.

Common Problems & Solutions

Problems that people run into are error messages like "the server could not be found" or "DNS name does not exist". These are actually very common issues, here are some solutions to the issue:

  • you may have typed the domain name in wrong
  • your DNS server doesn't have an entry to the domain name you've entered
  • can indicate that there is a problem with your firewall
  • you might be offline, check your connection
  • the server hosting the website could have been changed just recently, in which case try again in a few hours
  • the IP address may have also change recently, also try again in a few hours
  • if you're in windows, go into a dos window and type: ipconfig /flushdns this will reload your DNS cache
  • if all else fails, try rebooting your machine

As you can see, DNS is one of the most important services for both the internet and business networks.  If you see have a problem, try the simple solutions provided above first. If those don't solve it for you it may be a deeper network issue and you may have to contact your internet service provide, or network administrator if you're in a business environment.