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Using the Mail Filter Utility

The Mail Filter Utility may be used for many different purposes, including managing spam emails and setting up auto-replies.

About the Mail Filter Utility

UC San Diego uses Spam Assasin, a program created for everyone to use for free. Our Mail Filter Utility harnesses the power of Spam Assassin, alongside another powerful and flexible tool for manipulating emails called Procmail, without forcing you to learn the ambiguities required to configure them by hand.

Most of this page is aimed at people using the advanced options of the Mail Filter Utility. Those who wish to enable simple spam filtering need only log in and press a button.

Recipes and How They Work

When an email is received from off-campus for a UC San Diego email address, it first passes through a central mail server before being passed on to its final destination. This central mail server puts the email through Spam Assassin for spam grading, regardless of whether or not you are using Mail Filter Utility. Spam Assassin assigns a numerical grade based on how many spam-like features are found in the email. The email is then forwarded to its final destination.

This utility works with ETS mail servers and does not affect how you receive your emails if you have your mail forwarded to a department or off-campus mail server. If your mail is not forwarded to another address, your mail server will first check for a set of rules about how emails should be handled. This set of rules is what you are editing with the Mail Filter Utility.

The set of rules is made up of recipes. When an email is received, the mail server looks at each recipe in the order listed in a file on your mail server. The Mail Filter Utility generates and edits that file, allowing you to create new recipes and change their order within the recipe list.

Mail Folders

Both of the advanced options, the spam filter and the simple mail filters, and many of the pre-written recipes give you the option to have mail moved to a folder separate from the inbox where mail is delivered by default. If you chose this option, the new mail folder will appear in your list of folders on Webmail the first time an email is delivered to that folder. If you use the Unix-based program Pine, a file will be created that tells Pine where these emails are delivered. This will also only appear after the first email has been delivered to that folder.

Logging In

The Mail Filter Utility needs to connect to the mail server twice, once to retrieve the old recipe file and once to deposit the new one. Use the same username, password, and server as you use to check your email. Once you have logged in, your web browser will keep track of your password. Close your web browser before you leave the computer.

Creating Recipes

Spam Filtering Options

Enable Spam Filtering

If you would like to temporarily disable any actions having to do with spam filtering, but want to save your settings, you can uncheck the box labeled "Enable Spam Filtering". The settings will still show up in your list of mail filters, but will have no effect on your mail. Once you have set up spam filtering, you can use the "Enable Spam Filtering" button to quickly enable or disable spam filtering without losing your settings.

Spam Filter name

The name you give your spam filter has no effect on how your mail is handled. Use it to help remember which filter handles spam when you are looking at your list of mail filters.

Spam Sensitivity, and the Two Levels of Spam Filtering

Spam Assassin checks emails for various characteristics of spam that make an email more likely to be spam than one not bearing those marks. Each time it finds something that is common in spam, it adds a small number to that email's spam score. Depending on the type of emails you receive, you can set your filtering higher (if many emails that are not spam are being marked as spam) or lower (if much of your spam is not being marked). Most people find that any email with a score higher than 8 is almost always spam and that email with a score higher than 5 are usually spam.

To give more flexibility in dealing with emails that may or may not be spam, all of the options associated with spam filtering are available twice, once for emails that are "probably spam", meaning that the spam filter saw lots of spam-like things in an emails, and one for emails that are only "possibly spam", meaning that the spam filter saw some, but not a lot, of spam-like features.

Your sensitivity for "probably spam" should be a higher number than the level you choose for "possibly spam" (usually between 8-10) so that only emails that are almost certain to be spam are handled there.

Since emails marked as "probably spam" have a very high chance of being spam, you can send these emails to a folder separate from your inbox and review them occasionally to make sure that no important emails were mismarked.

The options presented when you first begin to configure Spam Assassin are suitable for most users.

Changing the Subject

You can configure the subject of spam to be automatically changed. For example, you can make emails scored as "probably spam" start with "*****SPAM*****" so you can easily recognize which emails are not likely to be worth reading. If you are using Eudora or Outlook, you will not be able to use separate mail folders on the mail server and this will be the only way to distinguish what is probably spam from what is probably legitimate.

Dealing With Spam

There are two options for handling emails marked as spam. The first is to deliver the email to your inbox, despite being spam. It is usually wise to do this until you are sure that everything is working correctly. If you elect to have emails delivered to another mail folder, you will be able to read your emails using Webmail and Pine without any additional configuration.

Cutting down on spam buildup

To make sure that you do not go over your quota where your spam is being stored, there is an option to periodically check for any emails that were marked as spam and delete them. You can specify how frequently this occurs. When the check is run, all emails older than that frequency that are marked as spam are deleted. For instance, if you specify that every seven days a check will be run to delete old spam, any email that is both older than seven days and marked as spam will be deleted once a week.

What to do when an email is not spam

If you find that emails from a particular person or about a particular subject are always being marked as spam when they are not, you can make sure that that email gets delivered without being marked as spam by setting up a simple recipe (described below) to "whitelist" the person. A "Whitelist" is a list of an email address that are never spam. For example, if you make many purchases from Ebay.com, but all your bid confirmation emails are being marked as spam, you could set up a simple recipe called "Ebay Whitelist," tell it to check the email address and make sure that it contains the phrase "bidconfirm@ebay.com," and instruct it to deliver those emails immediately to the inbox. After creating this recipe, you would use the arrows in the list of recipes to make sure that this list appears before the Spam Assassin recipe.

Pre-Written Recipes

A number of recipes have been pre-written, so that you only need to fill in a few details to create a functional recipe.

It is important to think about where in the list of recipes these should be placed in order to work correctly.

Whitelist: Always deliver emails from someone

Use this tool to make sure that emails from particular people are never marked as spam. Just enter in the box a list of email addresses whose emails are never spam. This recipe should be somewere above the spam filter recipe in your list of recipes.

Blacklist: Always delete email from someone

Use this tool to ensure emails from particular people don't bug you ever again. Just enter in the box a list of email addresses and choose whether their emails should always be deleted or whether they should just be dumped in another folder.

The blacklist should be the very first recipe. If an email address in the blacklist is found, the email will be deleted or delivered immediately.

Vacation Notice: Automatically reply to emails

If you won't be able to respond to your mail for a while, you can use this recipe to let people know you might not get their emails for a while.

Whenever an email arrives, it will automatically send a reply of your choosing. Type your email in the large box, enter how many days the Vacation Notice should run, and decide whether someone sending more than one email should be alerted to your absence every time.

Do not place this recipe after any recipes that delete unwanted mail (such as the spam filter, a blacklist, or the duplicate filter) or after any recipes that handle mail from "non-people" (such as mailing lists), since you probably do not want to send your vacation notice to these emails. After a vacation notice is sent, recipes lower in the list will continue to be run.

Forward a copy to another address

If you have another email address where you read your mail, and you would like to be able to read them from both places, use this tool to send a copy of all your emails to another address.

If you would like your mail to be delivered only to one other email address, use the Mailbox Destination Tool. If you change your mail destination using that tool, you will be unable to use Webmail to read your mail and any mail filters you have set up with this site (including spam filters) will be ignored.

Do not place this recipe after any recipes that delete unwanted mail (such as the spam filter, a blacklist, or the duplicate filter), or after any recipes that handle mail from "non-people" (such as mailing lists), since you probably do not want to forward these kinds of emails. After forwarding the email, recipes after this one will continue to be run.

Mailing List Sorter

If you have signed up for many mailing lists, it may be convenient for emails from each list to be automatically sorted into their own folder.

Using some complicated logic, each email is scanned for indications that it is a mailing list. If it appears to be a mailing list, the list name will be guessed, and the email will be delivered to a mail folder with that name, appended to a prefix of your choosing. You can also use this to redirect "This email is intended for everone in the following majors/minors" emails to a separate folder.

Sometimes mailing lists are spammed just like normal email addresses, so you may want to place this recipe after your spam filter. If experience shows that emails bound for the mailing list are marked as spam, you will want to either move this recipe before the spam filter, or add the mailing list's address to the Whitelist. If an email is deemed to be from a mailing list and is delivered to its list's folder, no further recipes will be run.

Large Email Sorter

One of the easiest ways to go over your quota quickly is to receive a few large emails that you don't realize are large. This recipe will filter any emails larger than a certain size into a folder in your home directory, where you have a much larger quota. Set the size for emails to be stored elsewhere and what the name of the storage folder should be.

This recipe should be the last recipe in your recipe list so the spam filter has a chance to delete large spam and any mailing list emails are appropriately filed away.

Duplicate Email Deleter

If you are plagued with receiving the same email over and over again (as can happen when you are subscribed to many mailing lists with common interests), use this recipe to delete or set aside any email that comes twice. This should be one of the first recipes in your recipe list.

Simple Recipes

Recipe name

Each recipe is given a name. This name has no effect on the operation of the recipe. It is only to help you remember what it does when you are looking at the list of recipes you have created. If you create many recipes, you will eventually create a recipe that you want to test emails with before any other recipe. For instance, suppose you receive emails from many mailing lists and you want these emails saved to a special folder. If you are an active person on the list, emails may be sent to you directly, so you might create a recipe that moves all emails with your address in the "To" field directly to your mail inbox. This setup helps sort out the everyday emails from those of most interest to you. Giving the recipes names that help you clearly remember their function will help you know that the one that delivers emails directly to your inbox should go before the one that moves all the emails from the list to the list's folder. Names like "Recipe 1" and "Recipe 2" makes this difficult. The more recipes you have, the greater the need for clarity.

Conditions: When to do something

Being accurate is necessary to creating a filtering system that works for you. Nowhere is accuracy more important than in specifying conditions. Each recipe can have up to two conditions. Make sure that at least one of the "enable" boxes is checked. If none are checked, no conditions will be created. Since an action is done as long as no conditions are unmet, the action for such a recipe would always be done.

The first thing to consider is in which part of the email to look for a word or phrase. This depends on what you are trying to filter out. If you want to stop a particular person from sending email to you, for instance, you would want the recipe to search through the email's "From" address. If you wanted to do something to emails about a particular topic that may come from many different people, you might have a recipe search in the subject line. If the subject line is not sufficient, you can search the entire email. You may wish to make sure that something happens to every mail sent personally to you (as opposed to mass-mailings to many people). You would then look in the "To" field of an email for your own email address.

There are many ways to interpret what you want to search for. One way is to look for the exact phrase. With this option, if you search for "UCSD Anime Club", the condition would only be met if the email contains exactly that. Capitalization would not affect this.

By setting it to look for "at least one of these words" that phrase, an email would only need to have "UCSD" in it to satisfy the condition. Emails with "anime" or "club" would equally satisfy the condition.

In contrast, setting it to look for "all of these words" will require that the email contain "UCSD," "anime," and "club," but they do not need to be near one another or in any particular order. The last option, "none of these words," means that if the email has any of the words "UCSD," "anime," or "club" anywhere in the email it will not satisfy the condition and will not take the action for that recipe.

An overview: We're searching for "UCSD Anime Club"
  Action will be taken with the condition...
If the email contains this... exact at least 1 all none
"This is the newsletter of the UCSD Anime Club." Yes Yes Yes No
"This is the newsletter of the Anime Club at UCSD" No Yes Yes No
"The first annual meeting of the Odd-ballians club will be this Thursday" No Yes No No
"Welcome to Aardvark Mail service" No No No No

Sometimes University email addresses will receive emails intended for the former account holder. For example, when Jeremy Smith got his email account he was assigned jsmith@ucsd.edu, but started receiving emails intended for someone named Julius Smith. Jeremy could set up a recipe that would affect all emails bound for Julius Smith by creating a condition that looked through the whole email for the exact phrase 'Julius Smith'.

Actions: What to do

There are four options for what to do to an email that satisfies all the conditions in a recipe. They are:

  1. Delete the email
  2. Forward the email
  3. Move the email to a folder
  4. Deliver immediately to your mail inbox.

Avoid deleting an email in most case unless you are very sure that the recipe will catch only emails you want deleted. Deleting an email is permanent. No record will remain of what the email contained, unless the sender saved a copy on their own computer. Use this option at your own risk.

Forwarding an email can be useful if you tend to check different email emails in different places. You could set up recipes to forward emails from friends to an address you check at home and leave school emails in your school mailbox.

To add or not to add?

When you are finished creating a recipe, click "Add this recipe". This will not change your settings on your mail server but will only update a temporary copy of your mail filters. Click "Log out, saving changes" from the main screen to save any changes.

Custom Recipes

If you know how to use Procmail recipes, entering a custom recipe gives you the flexibility to do whatever you want. You are prompted for a recipe name and the name has no effect on the operation of the recipe, but makes sorting recipes easier. There is also a text field where you can enter whatever Procmail commands you desire. There is no verification of any sort. Your mail will be filtered according to whatever you specify. You should only do this if you are very familiar with Procmail commands.

Saving Your Recipes

To log out, you can click either:

  • 'Log out, saving changes' will copy the file containing your filters to your mail server and delete the temporary copy you have been working on
  • 'Log out, DO NOT save changes' will just delete the temporary copy, and any changes you have made will be lost.

If you do not log out, no changes will be saved. If you hide the advanced options, your changes will not be saved unless you enable or disable the quick spam filtering option.

Changing Your Recipe Order

The higher a filter is listed, the sooner it will have a chance to filter an email. If one filter does something to an email, no other filters will get a chance to do something to that email. Use the up arrows to ensure emails pass through a particular filter before others.