  Unsolicited Bulk Emails (also known as Spam) are undesirable emails sent to
massive number of users. Spam emails consume the network resources and cause
lots of security uncertainties. As we studied, the location where the spam
filter operates in is an important parameter to preserve network resources.
Although there are many different methods to block spam emails, most of program
developers only intend to block spam emails from being delivered to their
clients. In this paper, we will introduce a new and efficient approach to
prevent spam emails from being transferred. The result shows that if we focus
on developing a filtering method for spams emails in the sender mail server
rather than the receiver mail server, we can detect the spam emails in the
shortest time consequently to avoid wasting network resources.
