How To... Use Pegasus Mail E-mail Filters

Overview

Of all the network and internet features people use, email is probably the most popular and most useful. You can you keep in touch with colleagues and other contacts in far-flung places and in a lot of situation you can exchange files with them as well.

Email has been with us since the beginning of the Internet. As email matured, the ability to take part in multiple user discussions came about through the use of mailing lists. Nowadays a lot of people get updates on changing websites, advances in research or other repositories of information, via an email message.

However, there are some drawbacks in this evolution of email. The ability to communicate with large groups of people has resulted in some mailing lists producing dozens of email messages in your inbox each day. Just two or three of these high volume lists could result in hundreds of messages to you each day!

With the addition of so-called spam - unsolicited email - your inbox can be almost unmanageable. You could find yourself deleting a lot of messages you would like to read, just so that you can keep up with the volume.

This scenario is a perfect example of why you should use email filtering.

Why Filter Mail

There are a number of reasons to filter your email:

  • manage the large volume
  • sort spam from the valuable messages
  • highlight mail from particular respondents
  • sort business mail by type
  • organize your mail for archiving
  • generally make reading email a lot more user friendly
Any good email program will offer a variety of filters to use. I will be using Pegasus Mail 3.12 as our example because that's what we use here on campus, but the general procedure should be roughly the same for most email programs.

What is a Filter

A filter is a rule or set of rules that examines your email and performs a particular action based upon what it finds in each email message. The action can range from deleting a message to moving it to a folder or highlighting it in a specific colour. Some programs will even let you respond to the filtered email by sending a pre-made message or sending a file. These would be advanced topics, probably not available in every mail program, and so not covered in this article. We will focus on methods to sort your mail, making it easier to manage.

Your First Filter

Probably the most useful filter you can have is one to separate junk mail or spam, from the rest of your email.

As with all filters, you must determine what makes a particular email different from all the rest, and then setup a rule to look for that part of the email. In this case, I will set a general rule that any email that is *not* sent specifically to my email address is potential junk.

Here's where you will find the tools to start making an email filter.

Your first decision is when to invoke the filter. I want this filter to be applied before I start to read my mail - I want to attend to the email addressed directly to me first - so let's choose to filter my new mail immediately when I open the new mail folder.

Here is the New Mail Filtering Rules dialog. This is where you define your filter.

As you can see there are no rules defined as yet, so click on "Add Rule" to set it up.

At the top of the Edit Rule dialog, (see picture below) is a drop down where you can tell Pegasus what "type" of rule you want. The simplest type is a Standard Header Match and that's what we'll be using. Feel free to click the arrow on the drop-down menu to see what other types there are. As you become familiar with filtering, you might want to experiment with the other filter types.

A little further down the dialog is a space where you can enter some text that you will look for. Because I want to create a filter based on email sent specifically to my email address, I will enter my address here.

Further down the dialog is a set of check-boxes. Pegasus will look at the header fields that you select here. Again, I only want to filter email sent directly to my address, so I have checked the "To:" box, meaning check the address the email message was sent "to".

Just below the field selection is an odd option, labeled "Trigger only if the test does NOT occur in these fields". This is an important check-box and an important concept. If this box is checked, your rule will be invoked if the text you specified above does NOT exist. I have this box checked, and so if Pegasus does NOT find my email address in the To: field, it will take the action I have specified just below. In this manner, the email addressed directly to me will remain in my inbox for me to read, and everything else will get moved somewhere else.

Speaking of which, the last section of the dialog "What to do when the rule is triggered" has another drop down menu. Have a look at it now. There are a lot of options here to choose from, but we'll just use a simple "Move" action. As soon as you select move, the "Select a Mail Folder" dialog opens with a list of your mail folders. Double click on the folder to which you want the mail to be moved. If an appropriate folder doesn't exist, click the "New" button as you normally would to create a new folder, then double click the newly made folder to select it. In this case I created a new folder called "Junk Mail".

You might be asking yourself why move the mail instead of deleting it? Well, there will be a lot of cases where mail you might want to keep isn't directly addressed to you, such as messages from a mailing list. we'll deal with those shortly.

Here is what the completed rule looks like

Click ok and here is what the rule looks like in the "New Mail Filtering Rules" list:

Each rule you create will occupy one line in the rules list and as you can see the rule is summarized in a kind of shorthand.

Under Rule Type we can tell the rule is applied to message headers and specifically it is checking for text that is NOT in the headers. Under Contents we can see that the To: field is being checked (hence the "T") to see if it contains the text "dpoole@upei.ca" - my email address. Under action, we can see that the rule if invoked will "Move" the email to a different folder.

Before you close the list be certain to click on the "Save" button or the rule will not be saved. Before you click cancel to close the list, notice that there are buttons to Erase a rule, or to Edit a rule. If you click on edit rule, the dialog you used to setup this rule will appear and you can make any adjustments you require.

Now I have a basic email filter that will be applied when I open my new mail folder. It will check the To: field of each and every message. If it does not find the text "dpoole@upei.ca", it will move that message to a folder called Junk Mail. If it finds the text "dpoole@upei.ca" in the To: field of the message, it will leave the message in the new mail folder for me to read.

Make the exact same rule in Pegasus using your email address and you will have your first email filter! Hurray!

Each day when you open your New Mail folder, you will see a tiny box with an hour glass in it, and a message that says mail filtering rules are being applied. Let a couple of days go by and watch how this rule works.

Be sure to check your Junk Mail folder to see what was moved by the filter. Make adjustments if necessary until you're sure it does what you want it to. This is just one rule though, and it won't likely serve your every need.

Next I'll make a filter that will take the messages I receive from my Mailing Lists, and file them accordingly.

A Sorting Filter

A few days have passed and you've been able to see what messages your first filter is working on. Essentially, anything that wasn't addressed directly to you, was moved to the Junk Mail folder. No doubt when you opened the Junk Mail folder, you saw some "spam", but perhaps also saw some messages that you don't consider Junk Mail.

The most likely candidates are messages that are delivered by an email list.

Email lists send mail in two basic manners. Some send a message with your email address in the "To:", while others send a message with some other identifier in the "To:", such as "CUPE 1870 Members". The messages from this second type of mail list are the ones that will get moved to the Junk Mail folder, even though they are sent directly to you.

In such a case it is better to build a filter based on what is shown in the "From:" Header. So let's do so. Below is our email from CUPE.

In the "From:" field these is a huge long name followed, in angle brackets, by an actual email address. We will use the email address rather than the long name. Why? Well, the long name is what the mail sender entered in their email program, and therefore it can be altered by the sender at any time. If this were to happen, your filter would no longer work properly.

However, the email address can not easily be altered by the sender.

So when we choose to add a new filter, this is what the dialog will look like when we are finished.

There are just a few differences from the last filter we made. This is still a Standard Header match, and we are still looking for an email address, but this time we are looking in the "From:" field.

Also notice that I have NOT selected the check box that will trigger the rule if the text doesn't appear in that field.

Finally, I have created a Folder called CUPE and chosen to "Move" these messages to that particular folder. Here is what the rule looks like in the "New Mail Filtering Rules" Dialog.

This is the type of filter you will use most often, one that sorts through your email and finds the addresses you know and then files those messages in a particular folder of your choosing.

The only drawback to filtering in this manner is that somewhere while reading your email, you'll have to open a series of folders to read all of your incoming mail. One alternative is to set up these filters so that they are invoked when you actually *close* your new mail folder.

Let's take another look at the Mail Filtering Rules menu of Pegasus Mail.

Notice at the extreme right of the menu, there are options for rules applied when the new mail folder is opened, *and* for when the new mail folder is closed. One method you could use is to apply your Sorting Rules when the New mail folder is closed. In this manner, questionable mail will remain in your new mail folder for your review. Then, when you close the new mail folder, mail for which you have setup sorting rules, will be shuffled into their appropriate folders for storage or later review.

Those are the fundamentals of creating and applying mail filters. Feel free to play around with some of the different options. As long as you don't choose the delete option, you won't accidentally destroy an important email message, although you might have to look around in some of your folders to retrieve if the filter doesn't quite work properly.

If you would like to setup some email filtering, but don't feel confident about doing, feel free to send me email dpoole@upei.ca and I will gladly set aside some time to help you out.

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