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Spam - What it is and how to fight it

Spam is a generic term for the advertisements and promotional emails individuals and companies send to most any active email account they can find. They use this as a fast, easy, and inexpensive way to advertise products or services to large numbers of people. This practice gets frustrating for the email users as they can be sent many emails they do not wish to read or even receive.

So - what can be done about spam emails?

What ITSS is doing

ITSS filters email at three different levels: a block-list filter, an anti-virus filter, and then an optional personal SpamAssassin filter.

Block lists: When email first comes into the campus, an initial filter compares each email message to a block list of known spam sites. All mail from these sites is immediately thrown away. We delete 50,000 to 70,000 messages per day based on block lists. (See the related article, Email block lists control the spread of spam, for more details.)

Anti-virus filter: Email next goes through our Symantec Anti-Virus (SAV) filters. SAV looks for both spam and viruses. We filter email coming to our campus as well as email destined out of our campus. In September and October 2004, SAV rejected an average of over 1000 problem messages per day. In response to an increasing number of complaints about annoying spam, ITSS increased the screening threshold on our SAV spam-filtering services on Monday, November 1. It will be interesting to see how much these numbers go up after this change.

SpamAssassin filter: Finally, email may be filtered by SpamAssassin. This is an optional filter that is set up by an individual user for his/her account. As an example, Linda Deneen, ITSS Director, uses SpamAssassin in combination with several ITSS mail filters. Using this combination, an additional 135 problem messages were filtered from her account in September and October 2004.

Number of problem messages rejected
Block lists 50,000-70,000 per day
Anti-virus 1000+ per day
SpamAssassin Varies by individual

However, despite our best efforts, there is no magic solution for stopping all spam. It is simply impossible to block all such messages.

What you can do

ITSS provides two tools that you can use to help filter out annoying spam: ITSS Mail Filters and SpamAssassin.

Mail Filters
Mail Filters allow our customers to sort their emails based on the 'Subject' and 'From' lines of any email message. These tools give users more power to control what messages reach their email accounts, allowing them to decide what is valid for them and what is not.
The Mail Filters can be set so that any email from a particular source is deleted before it gets to your Inbox. This technique will not eliminate all spam emails and will not stop "one shot" spammers, but it will stop emails repeatedly sent from the same source.
SpamAssassin is a program that allows you to filter out unwanted email or spam on your UMD email account. SpamAssassin uses rules to evaluate each email message as to whether or not it thinks it is spam.
Please use this product carefully. No spam filter is foolproof, and SpamAssassin may identify some legitimate email as spam. For this reason we recommend storing and reviewing spam before deleting it. Email most likely to be misidentified as spam includes newsletters, messages from listservs, and legitimate mail with certain keywords in the subject header.

To use Mail Filters or SpamAssassin, go to: Enhanced Email Features

Additional tips

Here are some basic "Spam Do's and Don'ts" from the Anti-Spam Home Page:

And, two suggestions from ITSS staff:

Spam Q & A

ITSS filters all incoming email for spam, plus I have SpamAssassin set for my account - why am I still getting spam??
Spam filtering is an imperfect science, and spammers are clever. They spend lots of time figuring out how to get around spam filters. Then the spam filter folks find new ways to find spam, then the spammers find ways around that, then.....

You get the idea, it's an endless cycle.

Why does some legitimate email get flagged as ***SPAM***?
SpamAssassin uses rules to evaluate each email message as to whether or not it thinks it is spam. SpamAssassin is not foolproof and may identify some legitimate email as spam. Email most likely to be misidentified as spam includes newsletters, messages from listservs, and legitimate mail with certain keywords in the subject header.

Unfortunately, spam filters, being programs, are sure to make some mistakes, which is why we recommend reviewing your spam box from time to time.

How can I avoid having my legitimate email tagged as spam?
  • Avoid using words or phrases written in all capital letters.
  • Avoid using multiple dollar signs all in a row.
  • Limit the number of urls you include in your message. Messages with many urls are often tagged as spam.
  • Avoid certain key words or phrases common in spam, such as "free" or "register now," especially in the subject line.
  • If you are sending an email to a large list of names, send a draft to yourself first to make sure it passes the spam filters.
  • If you use Mulberry, you can click on the "Show message header" button to view the Spam-Report for that message, as shown in the following sample:

Is the new anti-SPAM law working?
The Controlling the Assault of Non-Solicited Pornography and Marketing Act of 2003 (known as CAN-SPAM) appears to be having little effect on the type or amount of spam being sent.

spam figures

CAN-SPAM requires that spam e-mail include a working return e-mail address, a valid postal address for the sending company, a working opt-out mechanism, and a relevant subject line. However, a recent study of email sent to U.S. inboxes in January found that less than 1% complied with the law.

Additionally, while the law allows for multimillion dollar fines and jail terms for some spamming activities, it is difficult to enforce. Spammers are continually finding new ways to hide their identities. Many of the recent viruses were created by spammers to hijack personal computers of others on the Internet to spread their messages.

Finally, only a small percent of spam originates from the U.S. Many of those responsible for sending spam are based outside the US and beyond the reach of this law.