How to Block Email Spam Part II


Online Email Services Offer Spam Blocking Filters For Your Email Account

Many people use Yahoo Mail or another online email service. Many Internet Service providers also offer a webmail option for online email reading. These services usually offer some sort of spam blocking email filters similar to those featured with POP mail. The use of spam filters is a bit confusing but helps reduce the amount of unwanted email. We will look at a couple of common spam filters for online email services.

Yahoo Mail

Yahoo Mail has a very simple spam filtering system. In your Yahoo mail folder click on the Options link on the upper right side. From the drop down chose “More Options.” Choose the “Spam” option on the left sidebar. Spam Guard is the name of the online mail filtering system. Tick the box next to the option to turn on Spam Guard. Chose an option for the frequency to empty the spam folder. There is a box to block any email address. When you have entered the options that you want click “Save Changes” above the main column. Now click “Back To Mail” at the top of the left sidebar. Spam filtering will be automatic. If you do receive a message that you think is spam you can check the box next to it and send it to the spam folder by clicking the “spam” button on the menu bar.

Zimbra Collaboration Suite

The Zimbra Collaboration Suite is a program installed on the servers of Internet Service Providers to make online reading of email possible. My ISP has Zimbra installed as an option for online Webmail. I can read my mail in a POP mail program such as Outlook or I can read it online with Zimbra. When I log into my Zimbra account I see a main column containing all of my current email and on the left is a smaller column for the account’s directory structure. At the top under the search bar is a small menu. Choose the Preferences button. In the preferences folder you will see several options at the top. Choose the Mail Filters option. You will see a work area in the center with the title Mail Filters. Choose the “New Filter” button. Now you have a Pop-up box and the cursor is flashing in a box called filter name. You can name the filter anything. If you are trying to filter out spam dedicated to weight loss products you might want to call it Weight Loss.

To set up the filter we must enter the conditions which will cause the filter to act. The first option is to set the filter to act on either “any” or “all” conditions. I chose “all” since I will be targeting mail which has a number of characteristics which recur frequently. If you chose “any” of the conditions you would need to set up many filters because you are defining things too narrowly. One single condition may exist in mail from all sorts of sources and may cause a lot of false positives. Suppose I set a filter for “any” condition and use the word “fat” as a string. This filter will act on all email that includes phrases like “lose fat fast”, “fat juicy steaks” and “Johnny’s fat lip”. Without adding more conditions we are not able to bring together the common traits that spell “Spam”. Our spam mails may include the words “fat”, “weight loss pills” and “sign up now”. This is why we want more than one condition to trigger the filter. By setting a filter with several conditions pertaining to weight loss we will get rid of spam mail and not the message from Aunt Jen who wants to tell about her “big fat bingo jackpot”.

The next step is to choose a section of the email document to set conditions on. The best ones for filtering spam are subject, from, to and body. “Subject” is important in that Spammers want to catch your attention so that you will read the email. The “Body” will contain many of the common terms that people use to try to sell weight loss products. “From” may help but not often since spammers change their addresses and names often. “To” is important since spammers will insert any name if they are not certain of what yours is.

From the “conditions” box choose “Subject” and then “Matches Exactly” as the Comparison Operator; the second part of the condition. There is a blank next to Matches Exactly. Enter the name of a weight loss pill in that slot; one which appears often in your mail. This condition requires that a word in the subject match the term you have entered into the blank. Now click the plus symbol and you will have another condition to fill. Choose Subject again. Choose “Matches Exactly” once again and then enter Rapid Weight Loss in the blank. You then may click the plus sign and add another condition. You may want to do this several times for words that you find often in the subject line. After clicking the plus symbol again you may choose “Body” from the left side of the condition. Now you may enter “Matches Exactly” as the Comparison Operator. Then a word that appears in the body.

As you add the conditions to this filter be careful that you are building a common combination of terms. By adding some rare words you will be making a filter which will rarely be activated. You should also be careful not to add words commonly used by your friends. This will make losing valid email less likely.

There are a several different Comparison Operators which do different things. “Matches exactly/does not match exactly” is an easy Operator to understand. The word we are filtering for must exactly match the term that you place in the blank. Does not match exactly will trigger the filter if the term is not found in the email. Matches Exactly will work if the spam always contains the word “Pills.” If the spammer makes a change in the spelling and uses “Pillz” instead the condition will not work.

The Operators “contains/does not contain” is a little less strict than matches exactly. If the chosen phrase appears somewhere within the subject or body the filter will trigger. Therefore a filter for Contains “diet pills” would match: “fantastic diet pills”, “harmful diet pills” and “illegal diet pills” but not “large diet pill.”

The third set of Operators is “Matches wildcard/does not match wildcard.” The wildcard allows you to match your chosen word with any string of characters that contains it. In other words the wildcard is a placeholder for other letters that you choose to merge with your test word. The asterisk (*) is the wildcard symbol. We set the filter to trigger with (*) placed at the beginning or the end of a word of choice. Then the filter is triggered no matter what combination of letters or numbers are added to the specific word. Therefore by using red*diet the filter will match “red apple diet”, “red pudding diet”, or “red heads don’t diet”. The wildcard is useful when the spammer merges words with other words. The tactic of merging words in the Subject line is a favorite one for spammers. You cannot use “Matches Exactly” Pills when the line is CheapEffectivePills. But a condition set for “Matches Wildcard” *Pills would work with the phrase CheapEffectivePills, or AnythingAnythingPills.

In the bottom part of the box there is a section for setting the action. The action is what the program does with all mail which fits the condition you set. Zimbra is not only for spam so some of the actions are not appropriate for dealing with email. From the drop down choose “Discard.” Now we are almost finished. You may have a number of other filters set up which will sort or flag mail rather than filter it for spam. All of the filters in the list will act on each email unless you state otherwise. You don’t want a piece of identified spam mail to go through the other filters and be acted on by them also. To prevent the other filters from acting on your spam mail check the box in the lower left corner of this spam filter. By doing this your spam filter alone will act on this mail and not the remaining filters. Finally click OK at the bottom of the box. You have set your first spam filter.

Filtering with Zimbra is a complex process. Some study of terms may be necessary for effective use. It might be necessary to use some trial and error before the filter works as planned. If you are still getting the spam mail go back and work the conditions again. If you think that you are losing good email you can go back to your filter and set an action to “Deliver to Folder” and have the mail sent to a folder in your account. Check the folder and if your valid mail is there go back and rework your filter. Spam operators change their tactics constantly so the filtering tactics will need to change also.

Many online email services offer a spam filter system. Services such as Yahoo Mail may not matter much to us since we consider them to be throw away email accounts. For many people, their main email account that comes with their ISP is more permanent and also more important. ISPs are offering Spam Filters now along with their other services. The filters in Zimbra Collaboration Suite are not as powerful as those in other packages which include software like SpamAssassin. Zimbra will offer some help when combined with filters in your Desktop software such as Outlook. More information on Zimbra is available from several sources. The best and fastest way to get help with spam filters is to ask a qualified Web Designer or IT Professional.


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