Spam is the mass mailing of advertising messages that are sent to users without their consent. Anti-spam technologies help filter unwanted messages and help you avoid cluttering your inbox with useless emails.
How antispam works
Antispam can be used on personal computers or remote servers. The filtering procedure is implemented by means of special software that is installed on the user's computer or on the mail server. A spam filter analyzes every email that comes to an e-mail using content analysis technologies and checking the sender's reputation.
The antispam system helps to recognize by the keywords used a letter that has an advertising character. After that, the system examines the sender's e-mail address, the information available in the e-mail service profile. The filter determines the number of people to whom the same message was sent. The fact of mass mailing most often indicates spam, and therefore the presence of additional sending addresses immediately lowers the message status for the antispam system.
After the program marks the letter with the "Spam" flag, it will be sent to the appropriate folder on the server, where it will wait for further user actions. If the mailbox owner confirms that this letter is really unnecessary, the program will immediately delete all unnecessary data from the system.
If the user thinks that the message contains the information he needs, the mail server program will move the file to the mail folder "Inbox", and the anti-spam filter will create a rule according to which messages from this sender will not be classified as advertising or malicious in the future. The user is often additionally prompted to manually configure message filtering by creating a list of trusted e-mail addresses that will not automatically be moved to the "Spam" category.
Antispam problems
Each vendor of e-mail client and server software tries to implement its own algorithm that will most effectively detect spam. However, even the most famous and effective solutions do not completely eliminate the filter error factor - none of the modern filtering services is able to determine with 100% accuracy whether a message is unnecessary for the user. Even the best security systems have a success rate of around 90%. The remaining 10% is accounted for by false positives of the system.
