According to Australian legislation about Spam policies, spam has been defined as "unsolicited commercial electronic messaging", embracing email, mobile text messaging (SMS) and some other electronic messaging.1
The methods employed by spammers to exploit the e-mail differentiate.
It was not allowed to authenticate users, verify the identity; no guarantee of message privacy or integrity was made. The only way recipients could determine the source of spam was to rely on the "From:" field and "Received:" headers. (Internet Engineering Taskforce, 2001) A sample, taken from Stopping Spam, is shown below:
The "From:" field is the most noticeable way to identify the sender, but it is also a very unpredictable way. It can be easily thought out by the message sender. (Lentczner, 2003) Spammers not often use an address they can be found at in the "From:" field, and usually, the address has either been forged or is the e-mail address of someone else. The "Received:" headers are a more obvious way of disguising spammers. A "Received:" header is added by each host that relays the message from its source to its eventual destination. Each of these headers contains the name and address of a system that relayed the message, as well as the name and address of the system that just passed it the message. Spammers are not abe to prevent intermediary systems from adding these headers while the headers provide only minimal protection because a thorough examination of the "Received:" header will be required to identify the real source of the message.
There are two popular techniques used by spammers to puzzle message recipients: using open relay sites (Yahoo! Anti-Spam Resource Center, 2004) to send mes ...