The messages that arrive at the CC mail server are categorized into spam which are directed to the SPAMBOX folder of the users, some are identified as containing a virus and automatically discarded, the actual messages that do not contain a virus or are not classified as spam are placed at the INBOX folders of the users.

Spam messages are filtered by the CC, by means of the spam filter operating on the e-mail server. E-mail identified as spam by this filter is directed to a specific e-mail box, referred to as SPAMBOX, located within the main mail folder of the recipient.

The main reason for sending spam messages to the SPAMBOX rather than deleting them is to give our users a chance to check if the identification was correct and not to lose a message that has mistakenly been identified as spam and sent to the SPAMBOX.

The spam filter software is dynamic and is able to increase its success rate by learning from our users when identifying a message as spam or an actual e-mail message. In the learning process, thanks to the frequency of number of words used, sender address, and other such header information, used in e-mail messages defined as clean or spam, the spam filter software decides on the probability of an incoming e-mail to be spam and marks those with a certain threshold level as spam. Then, these e-mail messages are carried on to SPAMBOXes. Theoretically, it is possible for this filter to identify messages correctly with 99.9 % accuracy. When the filter is constantly fed with clean/spam messages, its success rate increases.

The expert staff at the CC, after much research done, have decided this filter system to be the best solution for METU users, and after meticulous teaching work on defining clean/spam messages to the filter, they have put the system into application. The software is at a process of constant learning due to its technical structure and renews itself according to the customer profile.