How to Filter Spam at Rutgers University
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What is "spam"?The term "spam" is computer slang for the electronic equivalent of junk mail. Spam floods message boards, newsgroups, mailing lists, and Rutgers e-mail accounts with unwanted, unsolicited, and often repugnant messages--usually advertisements, promotions, or deliberate disruptions. It is also a flagrant violation of membership agreements with most Internet Service Providers. While spam is often identified as "large numbers of messages", even just one unwanted message to someone can be considered spam. The term is attributed to a sketch, performed in the 1970s by the British comedy troupe Monty Python, about a repetitive breakfast menu in which each item has more Spam (the canned meat product) than the previous.Spam is a problem for all e-mail users. It has been determined that 80 - 90% of all e-mail coming into the University's central e-mail servers is spam. For example, in July 2007, the New Brunswick faculty/staff e-mail server received 66,088,392 e-mail messages. Of those e-mail messages, 41,264,942 messages we detected as being spam or viruses and were blocked. This is not only a problem at Rutgers. Spamcop.net, a website dedicated to reporting spam worldwide, has estimated that 11.5 spam messages are sent out every second.
Currently, OIT offers an e-mail spam filter based on a popular program called SpamAssassin. With that program, all incoming messages are assigned a score according to complex formulas that determine the likelihood of a given message being spam. Individual account holders can then determine what to do with messages that exceed a particular score (e.g., delete them). Setting up or disabling spam-filtering on OIT systems
Determining what is spam There are various ways that a message can be classified as spam. The webtool allows three methods of spam filtering: 1. user address, 2. domain name and 3. filter level. The spam filter can be set to work with those three types of filtering, depending upon needs and preferences. 1. Spam filtering by user address Filtering spam by user address requires the e-mail address of spam senders be specified in the appropriate fields of Section 1 of the Webtool spam Filter (Note: use of this filter will catch all mail from an address, even legitimate messages.) ![]() This is the least effective of the three options for general spam control, as the user must continually add new addresses to filter out new messages. However, if you are beset with messages from a particular correspondent which you no longer wish to see, this is the option to use. 2. Spam filtering by domain The spam filter can also be set to detect spam by domain, which is the name of the organization in an e-mail address. For example, in an e-mail address of NetID@rci.rutgers.edu the domain is rci.rutgers.edu. Examples of some other well-known domains can include aol.com and Amazon.com, to name just two (Note: use of this filter will catch all mail from a domain, even legitimate messages.) Filtering messages based on domain, or e-mail address is called a Black List Enter the domain names from which spam is to be detected into the fields in the middle portion of Section 1 of the Webtool spam Filter: ![]() This is somewhat more effective than the previous option, as it catches all messages coming from a particular domain, rather than just those of a particular account at that domain. However, as a general spam-prevention method, it is not much of an improvement, as you continually need to add new domains. Also, it must be noted that spammers frequently fake e-mail addresses, including entire domains. If you attempt to put in a domain that does not actually exist, a warning message will be shown and your changes will not be saved. Remove the invalid domain and resubmit the changes. Exempting domains and e-mail addresses If legitimate e-mail addresses or domains are consistently being filtered by the spam filtering software, exceptions can be made with the tool to allow these messages to go through. This method is referred to as setting up a White List Enter the domain name or e-mail address on which the exceptions should be made by filling out the bottom half of Section 1 of the Webtool spam Filter. ![]() NOTE: Black Lists take precedence over White Lists. This means that if the domain aol.com is listed in the Black List, and user@aol.com is listed in the White Lists, the user@aol.com e-mail's will still be treated as spam. 3. Spam filtering by a filter level The filter level establishes a very important criterion: messages above a chosen value will trigger a response from the filter and route those messages accordingly. Messages labeled as spam can be handled in three different ways:
Rutgers sets a default trigger value of each account's filter at 5 on a 1-to-30 scale, with 1 a strict setting and 30 a very lenient setting. The former will filter almost all e-mail messages, while the latter will filter very little. If you put purported spam into AUTO-DELETED-SPAM, OIT recommends the median level of 5. However, if you are directing the filter to delete spam immediately, we recommend the safer level of 10. There is no way to recover a legitimate message which the spam filter has automatically deleted upon arrival. Deciding what to do with spam messages Once a message has been flagged as spam, you next need to decide what should be done with that message. You have several options.
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You can control how frequently the messages in AUTO-DELETED-SPAM are deleted. Click on the pull down menu in the "Keep messages around in this folder" line and select the number of days, between 1 and 30, then click the "Submit" button. NOTE: Those who use the POP server for incoming mail will be unable to view the contents of an AUTO-DELETED-SPAM folder, and risk missing legitimate messages that may be placed there. OIT recommends configuring Mozilla Thunderbird or Outlook Express to the IMAP protocol to send and receive mail. Those choosing to route spam into folders for viewing later (e.g. the AUTO-DELETED-SPAM folder) will need to re-subscribe to their e-mail folders on the server. While programs such as Mozilla Thunderbird and Outlook differ in appearance, they generally work the same in terms of managing e-mail and folders. Instructions for subscribing to folders in each software product are available by clicking on the respective link:
What else can users do to stop spam?There is no 100% fool proof way to stop spam entirely. There are ways to cut down on the amount of spam an account receives.
Where can I get help?Please call the NBCS Help Desk at 732-445-HELP (4357), or visit Room 013, Hill Center, Busch Campus. You may also write to "help" on the system where your account is located (e.g., help@eden.rutgers.edu for Eden accounts, or help@rci.rutgers.edu for RCI accounts) or consult your Unit Computing Manager or Unit Computing Specialist. |



