Why have I been receiving so much spam?
(and how to block it)

  • Are you getting a lot of spam lately?
  • Have you wondered how some seem to be from a familiar address, or are addressed to someone familiar?

One of the unfortunate realities of E-mail on the internet, is spam.

Spamming is the abuse of electronic messaging systems to indiscriminately send unsolicited bulk messages. Spamming remains economically viable because advertisers have no operating costs beyond the management of their mailing lists, and it is difficult to hold senders accountable for their mass mailings. Because the barrier to entry is so low, spammers are numerous, and the volume of unsolicited mail has become very high.

E-mail spam has existed since the beginning of the Internet, and has grown to about 90 billion messages a day. It is believed that about 80% is sent by fewer than 200 spammers. They collect E-mail addresses from chat rooms, websites, newsgroups, and viruses which harvest users' address books. These are often sold to other spammers.

We believe that one cause of of the increased spam traffic is an infected computer in the network. When a computer is infected with a virus or trojan the spammer maybe able to harvest listings in the address book. Thus, if a computer is infected, not only is it a problem for that user, but it is a threat to everyone else on the network because they will receive an increase in spam.

Users of the @princeton-ma.us E-mail system receive a high-degree (not perfect) of protection from viruses and spam entering through their E-mail messages. However, viruses and trojans can infect a computer by originating in websites, downloads, etc., so a good virus protection tool on every computer is essential.

We strongly recommend that you install virus / trojan software on your computer, scan your computer regularly and keep the virus tool up to date. McAfee, Norton and AVG offer such tools.

Click here to read McAfee's "Tips to Avoid Spam".

There are two ways to block spam from getting to your inbox. One is to use the Spam Assassin feature and the other is to use the Blacklist feature:

Using Spam Assassin:

  • Login to your account on the mail server (www.princeton-ma.us/webmail) and select Options.
  • There's a choice for E-mail Filters.
  • Under Spam Assassin, change the Junk mail with SPAM level higher than:.to a lower number (I recommend 4).
  • Click on the Set tab.

You should check the Junk Mail folder occassionally to ensure that you're not blocking desired messages.

Using the Blacklist feature:

  • First, write down the E-mail address of the offending sender on a piece of paper. You'll need to type it in later.
  • Login to your account on the mail server (www.princeton-ma.us/webmail) and select Options.
  • There's a choice for E-mail Filters.
  • Under Spam Assassin, select Manage.
  • You'll see a choice in a box that says "Whitelist Sender". Use the pull down arrow to its right to select "Blacklist Sender".
  • Type in the offending E-mail sender's address.
  • Finally, click on the Add button.

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How can I adjust the performance of the spam filter,
view messages that have been blocked by the spam filter,
or establish a 'white list'?

Spam is an E-mail message that you find objectionable. A spam message may contain inappropriate language or content, or just be an annoying advertisement. Since there is no absolute definition of spam, what is obnoxious to one person maybe acceptable to another. Thus, a spam filter has the challenging task of selectively blocking some messages while letting valid E-mail get to your Inbox.

The princeton-ma.us E-mail system has built-in software (Spam Assassin) that attempts to block spam messages from reaching your Inbox. It has some built-in cues to identify potential spam, but it can only do part of the job itself. There are a few adjustments that you can make to tailor the spam filter to your personal tastes:

  • Setting the probability level. As a default, all mailboxes have been preset to 70%. That means that if Spam Assassin believes that itís more than 70% sure, it will block the message. You can change this level for your mailbox.
  • Electing to collect blocked messages in a ĎJunk Mailí folder for later review. This folder will store blocked messages for up to 14 days, and gives you the chance to make sure that youíre blocking only messages that you donít want.
  • Establishing a Ďwhite listí. Manage a list of addresses that otherwise get blocked by the Spam Assassin filter. (This is a common problem if you occasionally receive international E-mail.)

All of these features are found under the Options / E-mail Filters tab on the webmail screen.

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