On Domains, Accounts and Addresses

One small caveat: I'm going to oversimplify a little, and perhaps some will disagree with the details, but for the purposes of discussion here on Taming Email these are my basic definitions for these terms. As with just about anything on the internet or computers, things could of course be made excruciatingly more complex. I'll try not to do that.

Domains

As I said, you probably know what a domain is. "tamingemail.com" is a domain. As is "hotmail.com", "microsoft.com" and "mac.com". Those represent business or organizations on the internet. In almost all cases, they happen to have a web site associated with them, though it's not technically required. Similarly, they all probably process email, though again, that too is not necessarily required.

By processing email, I mean that email directed at some address "@" one of those domains is handled by some mail server or servers specifically for that domain. In fact, all the "outside world" really knows is that "mail for this domain is is handled by that server". For example as I write this mail for "tamingemail.com" is handled by "mail2.pugetsoundsoftware.com". When mail is sent to any address @tamingemail.com, it actually gets routed to mail2.pugetsoundsoftware.com, where it's then processed and routed to the correct individual recipient.

A key factoid is that any domain can have a virtually unlimited number of email addresses and accounts associated with it. Think of all the possible email names to put in front of the "@" in "@tamingemail.com" - as the owner of that domain, I could choose to define any of them.

Accounts

For purposes of my discussions, an account is a mailbox. Seems simple, yes? And, in many cases it is, because in many cases there's a one-to-one relationship between an email address and a mailbox.

I'll put it another way - an account is use to read a mailbox. In order to download or read email in a mailbox, you must supply your account name and password.

In many cases, the email address actually identifies the account. For example a Hotmail email account is completely identified by the corresponding Hotmail email address. The upshot is that if you want to change your Hotmail email address, you must do so by creating a new Hotmail account.

Not all accounts are identified by their email address. A good example was my old Verizon account: the "User Name" information was some cryptic string like "res1234", which isn't an email address at all. But the email address that corresponded to that account was more as expected: something @verizon.net.

In my email program's account configuration, I had to specify that cryptic name as my "User Name" (with its password, of course), and then separately when it asked for my email address I would put in my @verizon.net address.

It was still a one-to-one relationship, though. One user name, one mailbox, and one email address that landed in that mailbox.

Addresses

An email address is name for a mailbox. It is not the mailbox - it's simply a name for that mailbox.

To put it another way - an email address is simply a way to put email into a mailbox. An email address simply tells the mail system, right down to the mail server for the specific domain, which mailbox into which the mail should be delivered.

So why is the distinction so important?

Because a mailbox (account) can have many, many names (addresses).

Whether it actually can in some specific instance is up to the email provider. As we've already seen, Hotmail is an example where you cannot - one email address implies one account, and vice versa.

Accounts and Addresses

So we've seen that accounts and addresses are related, and that they "meet at the mailbox". Addresses put things into the mail box, and accounts are how you take things out. How does that translate into actual usage?

Well, depending on your email provider, you can often define several different email addresses that all deliver into the same mailbox. For example it's not at all uncommon for the various standard email addresses like "abuse@", "postmaster@", "webmaster@" and so on, all to deliver into the same mailbox - the mailbox of the administrator for that mail server. I actually go so far as to have many email addresses on my "ask-leo.com" domain, but not one account. All the email on that domain is delivered to accounts on one of my other domains.

Mailboxes, identified by you account are what you access or download. That means that regardless of how the email got there, regardless of what address was used to get it to that mailbox, when you download email from that account, all the emails in that mailbox are part of the package.

That has interesting implications. That means you can control what email gets downloaded when by perhaps having more than one account. You can also perhaps segregate email based on what address it was sent to, regardless of when you download it.

In fact, both will be key components of some of our tricks to taming email.

The Office Building

Domains, accounts and addresses still a little unclear?

Time for a metaphor.

Imagine a large office building. This office building has hundreds of employees, and deep, down in the basement is a mail room for the tons of paper mail delivered by the postal service every day.

• The "domain" is the address of the building. The postal service simply delivers all mail for anyone in that building to the back door, where they drop it in a lump. That's the equivalent of the internet handing off all email for that domain to the mail server for that domain.

• The "mail server" is the team of hard working mail clerks that pick up the mail from the back door, carry it down to the basement, and start sorting it into its respective destinations.

• Each employee has a physical mailbox - that's their "account" in which they get their paper mail. The mail clerks examine each piece of mail, and shove it in to the corresponding mailbox.

• However, each employee might go by several names ... each of those is an "address". I might go by "Leo", "Leonard" or "Chief Technology Officer", and the mail clerks know to deliver all the email addressed to any of those to my one mailbox.

• And finally, there's the guy that takes the email out of your box and delivers it to your desk. He's your "mail program".

I could even extend the metaphor a little further ... perhaps the mail clerks recognize and automatically throw away junk mail - that'd be your spam filter. Mail that the clerks don't know how to handle, so they mark it "unknown; return to sender"? That's a "bounce".

And so on.

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As I said, these are somewhat fundamental concepts that we'll be referencing as we get your email under control.

Think of them as the whip and chair you're holding as you tame the beast that is email.