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DNS – Domain name server

 

        We are going to try and supply a easy explanation of DNS here if there is anything that anyone does not understand please feel free to e-mail us.

 All of us at one point or another have tried to go to a page and an error comes on our screen that says DNS error please contact your ISP etc etc.  Any errors that say anything about DNS are related to the same thing (Well almost every one).

 A simple explanation of DNS is:  When we go onto the internet and want to go to a page we type in a NAME, But all the machines on the internet use numbers called ip addresses (e.g.: 24.70.196.240) so how does the computer know where to go, that’s where a DNS server comes into play.

  A DNS server has a list of names that are mapped to ip addresses e.g.:

  www.techeez.com => 216.86.100.70    

   www.yahoo.com => 216.115.108.245

   etc

   etc

So this is what happens you type in an address in the address bar.  Your computer goes out to the DNS server that your computer is using and asks do you know where this address is, if it does it will tell your computer and bobs your uncle the page shows up, if it does not know where the address is it asks another DNS server and so on.

Question and answer:

What is an "A" record?
An "A" record, also called an "address" record, ties a domain name to an IP address. If there is a server on the Internet that is configured to handle traffic for this domain, you can enter the name of the domain (like "www.NetworkSolutions.com") and the IP address of the server (like "209.81.71.236"), and almost immediately, anyone surfing to that domain connects to the correct server.

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What is an "MX" record?
"MX" ("Mail eXchanger") records are used to specify what server on the Internet is running e-mail software that is configured to handle e-mail for your domain. If you want your ISP to handle routing the e-mail for your domain to you, you need to specify the domain name or IP address of your ISP's mail server. In addition, you can specify the rank of each mail server when you have more than one. Make sure your ISP knows that you're using their servers to route your domain's email, or all your e-mail will "return to sender"!

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What is a "CNAME" record?
"CNAME" records, short for "Canonical Name", create an alias from a domain name to another. You could create an alias from "yahoo.mydomain.com" to "www.yahoo.com", and every reference to "yahoo.mydomain.com" would go to the other location, regardless how yahoo changed their IP addresses! Be careful, however; CNAMEs won't work everywhere. If you create an MX record, and the name used for the mail server was defined using a CNAME, you might lose e-mail.
 

So if you are having errors showing up that say DNS error a couple of things can be wrong.

  • The ISP’s DNS server could be down (Normally the ISP’s make certain that these box’s stay up) but if it is down be patient because it will be up as soon as they can get it up (normally not longer then 10 min’s or so)
  • Your ISP might have given you a static IP (see Static and Dynamic ip’s explanation) and you have not entered you DNS servers correctly or you miss typed one.
  • The piece of equipment that you connection to is having a problem seeing the DNS server (your ISP is normally right on top of these things and should have it fixed with in a reasonable amount of time.)
  • Or the name you typed in the address bar is wrong (miss spelt or a comma instead of a dot) or and this is a big one the people who own the site may have gone out of business/sold.