Now-a-days, email becomes a powerful tool for communication as it saves a lot of time and cost. Like every powerful medium, however, it is prone to misuse. One such case of misuse is the blind posting of unsolicited e-mail messages, also known as spam, to very large numbers of recipients. Spam can be defined as unsolicited (unwanted, junk) email for a recipient or any email that the user does not want to have in his inbox. These junk mail not only wastes user time, but can also quickly fill-up file server storage space, especially at large sites with thousands of users who may all be getting duplicate copies of the same junk mail.