Spam FAQ

The SPAM Problem

Spam is a huge problem. A study from April 2004 shows that 82% of U.S. Email is now spam, viruses and other unwanted content. Each day the situation only grows worse. Combating spam requires a multipronged approach:

Automatic Spam Filters

One of the best ways to mitigate spam is to use the automatic spam filters builtin to your email client. The latest version of Outlook and Mozilla come with automatic spam filters. See these links for instructions on using them:

Spam Tagging

If your email client does not automaticly filter spam, and you're not willing to upgrade to one that does, then spam tagging is for you. UNR aggressively scans all email (using SpamAssassin) at the campus gateway and tags the messages it thinks are spam.

SpamAssassin calculates a score for each message based on the probability that the messages is spam. Messages that score above 5 are tagged with LIKELY SPAM in the subject line. Create a filter for "LIKELY SPAM" and move the messages to a folder called Junk.

Then periodicly scan your Junk folder for false positives. I find identifying a few false positives in my Junk folder is much easier than identifying all the spam in my Inbox.

Message Filters

The UNR Helpdesk provides a comprehensive page describing how to setup mail filters for a variety of email clients and lists other resources to help you deal with and prevent spam. I highly recommend reviewing this page.

procmail

If your email account is not hosted on the Microsoft Exchange Server (which does it's own server-side filtering ) you can use procmail to filter your email before the server delivers it to you. The advantage of server-side filtering is you only set it up once on the server and not on each of your email clients. This helps when you read mail from multiple places.

Here is a procmail recipe to filter messages that have been tagged as spam. Create (or edit) $HOME/.procmailrc and add these lines: 

:0H
* Subject.*LIKELY.SPAM
$HOME/spam

See this procmail tutorial to help you get started.

Webmail (Equinox & Fallon) has a tool to setup procmail filters.

Preventing Spam

So far we've described how to deal with spam you're already getting. Now we'll discuss what you can do to stop getting more spam. The simple rule here is never give out your email address, at least in an unprotected way that causes you to get more spam.

Email Harvesters

Spammers use harvesting programs to scour websites looking for email addresses. To combat them, make sure your email address never appears on a website in a form that's easy for the scanners to harvest.

Obscure or Encrypt Email Addresses

Fortunately many harvesters are not very smart. With some extra work you can obscure or encrypt the email address you put on the web making it more difficult to harvest,

Here are some tools to obscure and encrypt your email:

Spam Motel

Spam Motel is an innovative way to combat spam. This free service enables you to generate bogus email addresses to use with your web transactions. Email sent to the bogus address is forwarded by the service to your real email account. When you start getting junk emails coming in via the bogus address, you can easily delete the address and create a new one. To effectively use this service, you'll want to generate a new bogus address each time you give out your email address.

Links

Spam Tools

MailWasher Pro $37/free trial
Spamex $9.95/Year
Spam Motel

Spam Education

Can the Spam Yourself
Spam tracking lessons
Scientific American

Spam Statistics

AppRiver Statistics
April 2004 Spam Study

Spam News

Spam by country
FTC Unveils "Dirty Dozen Spam Scams"
FTC Spam Site
Microsoft Spam Site

UNR Email

WolfMail
Outlook Web Access
UNR Helpdesk

Last updated: Thu Feb 28 17:41:59 PST 2008