www.cryer.co.uk
Brian Cryer's Web Resources

Anti-Spam

This site does not maintain any mailing lists and most definitely does not send out spam. Any unsolicited e-mails appearing to be from this site are fraudulent, please delete them.

Page contents

Anti-spam notes and resources for websurfers

What to do if you receive spam

The golden rule when receiving spam is don't reply to it - in any way:

  1. Don't reply to the sender of the spam. The e-mail address that the spammer is using is often forged. Your e-mail will either be returned or you may end up aggravating the administrator at a perfectly innocent domain, who may already be suffering under a large number of non-delivery returns anyway that they are not responsible for. (This incidentally is the reason for the interest in spam from this site.)
  2. Only read spam off-line. If your mail tool supports it (or if you connect to the internet via a modem) then get into the habit of reading your e-mail off-line. This is because some modern spammers can detect that you have read the e-mail because when images in the e-mail are pulled back from the server they have your e-mail address encoded in them. This in turn lets them know that your e-mail address is active and therefore worth sending more spam to!
        Outlook (not Outlook Express) has an option to "auto-preview" messages. This allows you to view the first few lines of the message but without the images. This is an alternative way of viewing messages without risk of notifying the spammer that your e-mail address is live. Other e-mail clients may offer similar capabilities.
  3. Even if the spam includes a way of being removed from the list, don't do it. All this does is to verify that your e-mail address is valid and it shows the spammer that you opened and read the spam and that therefore your e-mail address is a good one to use again.
  4. Don't every buy from the sender of spam - doing so encourages spammers.

Just delete it.

Anti-spam notes and resources for webmasters

E-mail harvesting

E-mail harvesting is the process of collecting e-mail addresses from web pages and UseNet postings for the purpose of putting together mailing lists. Harvesting is performed by robots that spend all day scouring the web for new e-mail addresses. E-mail harvesting is quite probably responsible for adding more e-mail addresses to junk/spam mailing lists than any other technique.

If you have ever wondered how the spammers got hold of your e-mail address then e-mail harvesting is the most likely culprit. A simple way to see if your e-mail address is listed on a website is to do a search for your e-mail address using a popular search engine such as google or alltheweb.

There are techniques that can reduce or eliminate e-mail harvesting:

  1. Use a graphical image file that contains your e-mail address. This keeps your e-mail address available to surfers but makes it impossible for harvesting. The disadvantage is that a surfer can't simply 'click-here' to e-mail you.
  2. Substitute characters in the normal '<h ref="mailto...' with their HTML ASCII equivalents. Every character in HTML can be expressed using one or more of its ASCII value, a shorthand name or in most cases the actual character used. For example the symbol '@' can be expressed using '&#064' or '@' (the actual character).

    For a full list of characters, their abbreviations and ASCII codes see www.cryer.co.uk\brian\misc\ascii_table.htm.

     If you are going to use this technique to try to hide the e-mail address from harvesting then it is probably worth hiding as much of the html line as possible, e.g.: instead of
     '<h ref="mailto:webmaster@cryer.co.uk">...'
    use '<h ref="&#109;ailto&#58;webmaster&#64;cryer&#46;co&#64uk">...'

    A serious disadvantage of this approach is that some html composers will translate the characters back automatically - undoing your work and leaving the e-mail address as exposed as before.

  3. Use JavaScript to disguise your e-mail address. There are a number of different ways to do this. A common approach is to generate the e-mail address in situ, for example:
    <script language="Javascript">
    name = 'webmaster';
    domain = 'cryer.co.uk';
    document.write('<a href="MailTo:' + name + '@' + domain
         + '">' + name + '@' + domain + '</a>');
    </script>

    This looks like: . This will hide your e-mail address from some e-mail harvesters, but not all.

Other than removing your e-mail address or using a graphic in its place, none of the other techniques for preventing e-mail harvesting are foolproof.

Other Links

The following resources contain information on how to deal with spam: