If each user has a unique mailbox on the mail server, there is no problem. But if multiple users are accessing a single mailbox with multiple aliases, you will have to use message rules to ensure that each user downloads only the mail sent to their alias. This is because the first user (or the first Outlook Express mail account) that downloads mail will automatically download all mail in the mailbox. This is simply the way POP3 mail works.

For example, Frank Lee signed up with a local ISP, A. Datum Corporation, for an Internet account with one POP3 mailbox with three aliases, thus four e-mail addresses in total. Frank’s e-mail address is frank@adatum.com. His wife Andrea will be using the alias andrea@adatum.com, while son Mark will use mark@adatum.com and daughter Cristina will use cristina@adatum.com.

Let’s begin with ensuring that Cristina receives only e-mail sent to her. Frank, who is the computer administrator, logs on as Cristina and opens her Outlook Express. He then creates a message rule:

1. Click Message Rules on the Tools menu, then click Mail
2. Click New
3. In the Conditions box, check the box labeled where the TO or CC line contains specific words.
4. In the Action box, check Do not Download it from the server.
5. In the Description box, click the blue underlined specific words.
6. Type the e-mail address, e.g. cristina@adatum.com.
7. Click the Add button.
8. Click the Options button.
9. Select where it does not contain.
10. Click OK.
11. In the Name box, type a meaningful name for the rule.
12. Click OK to close the Message Rule dialog.

The Rule Condition Options lets you make a rule inclusive or exclusive.

Mail that is not addressed to Cristina will not be downloaded.

Frank will now have to log on as Mark and create a similar rule to exclude mail not addressed to him, and then as Andrea to exclude mail not addressed to her. The final step is for Frank to create his own rule in his own User account. Frank’s rule however must use a different Condition to ensure that no mail is left on the server. His condition must be:

Where the TO or CC line contains cristina@adatum.com, or mark@adatum.com, or andrea@adatum.com
Do not Download it from the server

Cristina, Mark and Andrea will now receive only mail that has their respective e-mail address in TO or CC. Frank will receive all other e-mail sent to the mailbox. It should be noted that any message sent to Cristina, Mark or Andrea with their e-mail address in the BCC (blind carbon copy) line will not be delivered correctly. It will then be up to Frank to forward such messages to the correct e-mail address.