When a user is given a blueyonder mail account, they are given five "mailboxes". Imagine them like US mailboxes, stuck on little posts outside your house.

If your user-name were aazz12345, then your five mailboxes would be named:

aazz12345
aazz12345_2
aazz12345_3
aazz12345_4
aazz12345_5

These are "physical" mailboxes in the sense that they are each self-contained on the mail server, and have nothing to do with each other. The only common factor is that they (initially) all have the same password applied to them (although this can be changed via the "Self-Help" pages of the blueyonder web site).

In fact, the only thing that says they are "your" mailboxes is the fact that only you know for certain your user-name, and only you (should) know your password.

Retrieving mail from each box involves:

1. Accessing the POP3 server at blueyonder.
2. Supplying your user-name as the...erm...user-name.
3. Supplying your password as the password.
4. Collecting the mail.

From the perspective of a user's PC, that is about it. Five mailboxes to access.

The perspective of what those mailboxes contain is a different matter.

Each mailbox has up to three "aliases". For example, aazz12345 could also be known as "Fred.Flintstone" and/or "Wilma.Flintstone" and/or "Pebbles.Flintstone"; aazz12345_2 could also be known as "Barney.Rubble", "Betty.Rubble" and "Bam.Bam.Rubble"; aazz12345_3 could also be known as "Dino" and "Hoppy" (no third "alias"); and aazz12345_4 could just be known as "The.Exalted.Grand.Poobah".

When mail arrives at the blueyonder incoming mail server addressed to "Fred.Flintstone@blueyonder.co.uk" the mail server examines the "user" part of the address (the part before the "@" sign"), looks it up, finds that this is an alias for "aazz12345", and directs it into that mailbox. Mail for "Dino@blueyonder.co.uk" is directed to "aazz12345_3", and so on.

NOTE: mail addressed to "aazz12345_3@blueyonder.co.uk" will also be directed to that box.

All OK so far? Good.

Now we get tricky. :-)

Mail which is sent around the Internet is sent in what is known as an "SMTP Envelope" that contains the sender's and recipients' mail addresses. Routing around the Internet, and into mailboxes, is all carried out using the information in that "envelope".

BUT when mail is put into your mailbox, whichever mailbox it is, the server strips off the envelope. Only the mail ("letter") inside the envelope is available to users. If the mail starts:

Dear Mr. Flintstone

it's easy to see who it was for.

Mail starting:

Dear Sir

or

The Occupier

is trickier to figure out.

This can lead to confusion. If mail is sent by someone To: "Fred.Flintstone@blueyonder.co.uk", and a Cc: is sent "Barney.Rubble@blueyonder.co.uk", the envelope is addressed to both recipients. On arriving at blueyonder, the envelopes are stripped off, and the mail inside placed into the mailboxes aazz12345 (for Fred) and aazz12345_2 (for Barney).

When Fred and Barney read the mail, they can see who was the main recipient, and who was the Cc recipient.

Suppose, in addition, the mail was sent Bcc: (Blind Carbon Copy) The Exalted Grand Poobah. The mail would be directed to aazz12345_4, but once the envelope was stripped off, there would be nothing on the mail itself to show why it was sent there. For The Exalted Grand Poobah this is no problem. He's the only person using that mailbox, so the mail must be for him, right?

What about mail To: Bam Bam Rubble, Cc: Pebbles Flintstone, Bcc: Dino?

When the Bcc: copy arrives in aazz12345_3, the pets have a problem. The envelope has gone. The mail itself clearly states that it was for Bam Bam, with a copy to Pebbles; but there is no indication as to whether it was Dino or Hoppy who was supposed to get the Blind Copy.

Now let's look at spam (Unsolicited Bulk/Commercial E-mail). Spam is rarely addressed to anyone in particular. It is "Dear Friend" or "Dear Occupier". Thus, when spam arrives in a mailbox, and the envelope has been thrown away, there is no way of telling to whom the spam was originally addressed.

Until blueyonder updates its mail system to record envelope details as part of the "Received:" headers of e-mail, or in an "X-EnvelopeTo:" header, this situation is likely to continue. There are seemingly valid reasons for not doing so (Section 7.2 of RFC 2821), but they arguably don't apply in the situation where an SMTP Message is being passed to a POP3 mailbox for collection.

Last Amended : 2002-08-31 by elfin
Original Author : Jellyroll