E-mail explained: Building Block 1 - DNS

The foundation of email is a system called DNS which stands for Domain Naming System

E-Mail Explained: Building Block 1 - DNS

Lets start with creating a list to make an easy comparison

Our World Computer World
Telephone Number IP Address (Internet Protocol Address)
Landline Website Address (www.yoursite.com)
Mobile FTP Address (upload files, photos etc)
Fax MX Records (IP address of email servers)
"Men with Moustaches" DNS Server (Domain Name System Server)

Lets start in our world - you have a unique company name and no other details

What you do have is the number for the "Men with Moustaches"

  1. you call them up
  2. Give them the company name (each company name is unique)
  3. They give you the numbers, Landline, Mobile, Fax
  4. You can now use one of the options to contact the company

Now we take the example above and apply it to the computer world for a website

Your computer will have access to the DNS Server supplied by the company providing your internet connection (ISP)

  1. Open Internet Explorer type in www.zebraIT.com
  2. Computer asks the DNS Server
  3. The DNS server gives your computer the IP Address for www.zebraIT.com
  4. Your computer makes the connection using the IP Address voila our site appears
Moving On........

Email follows the same principal

When you setup your email client (Outlook, Outlook Express etc) you are given details for a SMTP Server for outgoing mail (you can take our word at this stage or use the step above for www.google.com then SMTP Server for the full description) for simplicity we will just call the SMTP Server your Email Server

Your Email server also has access to a DNS Server

  1. Your Email Server receives a request from your email client to send an email
  2. The email address is demo@zebraIT.com
  3. Your Email server asks the DNS Server for the MX Records for zebraIT.com
  4. The DNS Server returns the IP Address for the zebraIT.com Email servers
  5. Your server connects to the zebraIT.com Email server
  6. Your server "Hello zebraIT email server"
  7. zebraIT email server "Hello Your email server"
  8. Your server "I have an email for demo@zebraIT.com"
  9. zebraIT email server "we have an email for demo@zebraIT.com"
  10. Your email server "here is the mail"
  11. zebraIT email server "mail received thank you and bye for now"

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