I often have people ask me the simple question, “How can I stop these spam emails?” I don’t know if you’ve ever noticed but in IT the short / simple questions users ask quite innocently are the hardest and longest questions to answer. After about the 100th time I’d heard this question I decided to put together a list of advice which I’m including below.
1. Check if your ISP has a facility to filter out spam before you receive it.
2. Check if your anti virus software has an option to enable spam filtering. If it doesn’t it may have a low cost upgrade to a version, which includes spam filtering.
3. If you are using Microsoft Outlook Express as your email client upgrade to the Open Source Thunderbird email client from the team who brought you the Firefox web browser. This includes an excellent spam filter and it’s free of charge.
4. Have two email accounts. For example you can easily set-up an account on G-mail and another on Yahoo. Use one for personal or business use and use the other when registering on web sites or mailing lists.
5. Never use your main email address when posting to mailing lists or newsgroups.
6. If you need to put your email address on a web page consider displaying it as a graphic rather than text – this will avoid spiders gathering your address automatically.
7. If you want a “contact us” feature on your web site, consider setting up a form that people can fill in rather than using the mailto: option. This will avoid spiders gathering the address automatically. If you set-up a feedback form you should also implement a Captcha – those difficult to read letters and numbers you get asked to key in to prove you’re really human.
8. Don’t encourage spammers by letting them know you’ve read their junk! Make sure your email client doesn’t display embedded graphics inside emails by default. Modern email marketing systems give the graphics in each email they send a different name. When your email program downloads the graphics from their web server they log that you’ve opened their email and they know they’ve got a good email address.
9. Think twice before you switch on an out of office reply. This is another sure way of encouraging spam. When you’re on leave why not route your email to another account for someone to monitor for you. Also consider that out of office replies often contain alternative contact details such as your mobile / cell phone number. These can then be used by spammers to start spamming you via SMS as well.
10. Never respond or reply to junk emails. I know it’s tempting to send an email back asking them to stop sending you this rubbish but you can be sure this will only encourage the spammers to send you more!
11. If you have your own domain name (for example yourcompany.com) check how your ISP has set-up your account. Until recently most ISP’s set-up domain names with catch-all email addresses. This means that the spammer can use what is known as a dictionary attack to flood your ISP and your email account with spam. They do this by reading each word from a dictionary in turn and try to send mail to it for example Apple at yourcompany.com, Ant at Yourcompany.com, Atom at Yourcompany.com. If you don’t want a catch all email set-up just let your ISP know, most will be only to pleased to disable this for you.
12. Try and avoid setting up generic emails addresses on your domain such as firstname.lastname@example.org and email@example.com. These generic addresses are now so common that spammers will always try these first.
13. If you have followed these suggestions and are still suffering from a lot of spam, check your spam filter to see what settings it has. You need to find a balance between receiving too much spam and rejecting good emails. Spam filters work by scoring emails, the more suspicious they are the higher the spam score. As spammers get cleverer they are finding ways to lower their score. This means you may need to progressively tweak down the threshold.
14. Train your spam filter. There are usually two key ways to do this. First add the people you want to receive emails from to your address book. This is sometimes known as white listing email addresses and your spam filter should leave emails from these addresses alone. Then on an ongoing basis if your spam filter lets a spam email through highlight the message and use it’s report spam option. If you do this enough it will gradually learn the characteristics of the spam you receive and the good email you receive and make a better job of separating them
I don’t think you’ll ever stop spam completely because there is really no sure way of defining what is and isn’t spam but with a little set-up work you can drastically reduce the amount of spam you receive.