Blog / The BIG Phone Book: How do Email and website requests find you?

This provoked a stressful phone call with the client.  I was explaining the minutia of the DNS MX record pointers.  You guessed it – TOTAL SILENCE on the other end of the phone.  As with most technologies, it can be a confusing mess of acronyms with too many cooks seasoning the soup.   So, it’s time to clear up a little confusion by explaining DNS (well, at least part of it).

DNS stands for Domain Name Server.  A Domain is the name that you own that is tied to your organization; Trinus owns,, and a few others. There are several global organizations that validate and track the names to insure there are no duplicates – or nothing inappropriate.  GoDaddy and Tucows are two common companies that can register Domain names.  Registrations are for a set period of time (ie: 1, 2, or even 5 years); they need to be renewed at the expiry date or the name goes back into the pool of available names to register.

Once a name is registered, there needs to be a mechanism for people to be able to find where to send content or requests.  For example, if you send me an Email, how does your Email system know how to find Trinus’ Email system.  That’s the function of DNS.  Here is the secret to DNS:

Think of DNS as several BIG PHONE BOOKS.

The entries in the phone books tell systems where to go to find the next chain in the address. Let’s follow the Email example to see how it works (simplified for clarity):

  • Your Email system needs to send your message to me at, so it sends it to the only place it knows, the outbound Email server that is pre-configured in your Email system. Frequently, this is maintained by your Internet or IT provider.
  • Now that Email server must send the message on. It does so by looking up the last part of the Email address (  It knows there are phone books that handle all the entries for .com names, so it queries one of the phone books.
  • The phone book tells the server to go to the Tucows phone book (because we registered our Domain with Tucows).
  • Tucows tells the Email server to go to is one of our phone books.
  • tells the Email server to deliver all Email destined for to the server, so it does.
  • looks at the incoming Email, filters out the SPAM and viruses, and then forwards the Email to
  • looks at the Email and knows to send dwhite@trinustech.comEmail to my inbox.
  • And then I get your Email.

There is a LOT of technical GOO that goes on in the background to deliver the Email, but I think you get the idea.  In fact, your Email may be bounced around to several servers globally as it makes it’s way to me (don’t ask why – it’s another topic).

And there are several settings required make the DNS system work properly (such as IP addresses and types of DNS records – Email and Websites to name two).  If there is just one little mistake in any of the phone book entries, then NO Email, NO website, NO anything.

It would be like you just disappeared.

Of course, there are lots of people managing all of these phone books, so cooperation is important. There are also strict protocols that are used to authorize changes to these records to insure changes are legitimate, so changing records can take time – sometimes days.

It’s important that your IT Provider understand the chain of command in the DNS records and be prepared to properly manage it.`

If you would like more information on DNS systems, hosting, or Email systems, please contact your Primary Technician.