Learn about spammer tricks

Open relay

During the Internet's early days, open-relay e-mail servers were designed to allow a third party to pass messages through closed mail systems. Still used in some legitimate business operations today, an open-relay server can process a message between a sender and receiver who are not local users. The chance to use an e-mail server that may be distantly located from the sender and receiver offers

spammers some address camouflage, although tracing them isn't impossible. Hijacking an open-relay server via the Internet is also attractive to spammers as they can use someone else's resources to send a mass of e-mail at a lower cost than using their own network.

Creative HTML

In blocking spam that is designed in HTML format, most spam filters recognise the special characters and formatting of HTML. However,

some spammers have taken advantage of the flexibilities of HTML to write commonly detected words in ways that filtering software fail to recognise as spam. An example might be typing the word 'mortgage' to appear vertically, with each letter underneath the other. The advantage for spammers is the HTML e-mail can display words written like this in their normal horizontal form, thus presenting an

easy-to-read message. Spam filters then need to understand how HTML is displayed to the user, not just scan the HTML code.