Mac® Security Bible

9.6. Stopping Spam

Spam, or junk email, has reached such epidemic proportions that it has put some people off of email altogether. For many people, spam constitutes upward of 90% of incoming mail, making it difficult to find legitimate messages and wasting enormous time.

There's no question that spam is annoying, but it's also a security issue. That's because among all the ads for medications and get-rich-quick schemes, spam may also include viruses, Trojan horses, and malware of other kinds; it may also contain phishing attempts, in which someone tries to induce you to type your passwords or other private information on bogus websites.

For these reasons and more, it behooves anyone concerned about privacy and security to take steps to reduce or eliminate spam.

If your Mac is on a corporate network and all your incoming email is filtered by your employer's mail server, you may have little spam to contend with — at least in your business account. However, most people encounter at least some spam, and even if your company keeps your professional email mostly spam-free, you may not have the same good fortune with your personal email accounts.

9.6.1. Understanding spammers

As you're trying to determine your strategy for fighting spam, you should have in mind who — or what — you're up against. It's natural to assume that every spam message is sent out by an individual or a company with something to sell, so your opponent is a (presumably rational) human. But that's a faulty image. ...