Technology Simplified

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Useful for:

  • People who are not concerned about the technicalities of e-mail but want to know more at a non-technical level.

Not relevant for:

  • Mail services accessed via a browser or people running their own mail server

More technical help:

Use the tags along the bottom of this article to explore other related posts.

When you set up your e-mail client you are prompted for 2 distinct sets of information; the incoming mail setting and the outgoing settings. This is because for you, as the end user, e-mail is actually two completely different process that are brought together by your e-mail client.

Outgoing Mail

Outgoing mail uses something called Simple Mail Transfer Protocol (SMTP). At the most basic level this is a simple relaying process. Your e-mail client sends the mail to an SMTP server which looks up the record for the domain you are sending mail to, that’s the bit after the @ symbol, and sends it. It uses the same process your browser uses to do this; for an explanation of this see our article “How Does: Your Browser Know Where to get Web Pages From“. Part of the record includes the address of the mail server that handles the mail for that domain.

Although at the simplest level this is what happens it is worth mentioning one other thing that complicates this explanation. If we allowed everyone to do this there would be even more spam than there is now. In fact in the early days of the internet there was no control at all and you could use any SMTP server anywhere to relay your message. Now your mail has to fulfil conditions before your Internet Service Provider (ISP) allows it to be sent. It either has to be:-

  • sent via the SMTP server the ISP provides (decent ISPs provide these, some don’t. I shan’t name the ones that don’t as some of them are amongst the biggest providers and I can’t afford the lawsuit. They argue that it’s about security; in reality it’s just a cynical ploy to force people to buy their mail services).
  • or sent via an SMTP server outside of your ISP‘s network and in that case your e-mail browser would need to log into that server to prove that you were allowed to use it. This is often called roaming SMTP.

The destination SMTP server knows what to do with the mail it receives which brings us to …

Incoming Mail

Your e-mail client will be configured to collect your mail from wherever your SMTP stores it. There are a number of different ways this can be done. The main ways you will come across are POP, IMAP, HTTPRPC over HTTP or Microsoft Exchange; we are soon to be publishing details on what the differences between these are but you don’t need to know anything about them for our purposes here. In every case the mail server will not release the mail until it’s sure it knows who you are. In the case of POP your e-mail client saves your mail locally and then clears the mail off the server. POP and HTTP are one of the most common methods of collecting mail.


If you are using POP then all of your mail will be on your local machine. This means that if you lose the machine you lose your mail. Most backup services you get, whether they are USB disk based ones or online ones, DO NOT back up your mail by default; you have to open up the configuration pages and add the mail files, if you know where they are. I say this because many e-mail clients don’t store the mail files in “My Documents” (why on earth not I constantly ask myself). At the risk of being opportunist let me remind you of our  On Line Backup service (see MinervaSafe or OLB).

221 · June 16, 2009 · Everyday, Guides · Tags: , , , , , · [Print]

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