Spam filter
System for detecting and blocking spam
Spam filters are systems designed to remove unwanted mail while allowing genuine messages through to the user's mailbox. They come in a variety of forms including simple desktop software, gateway software installed on mail servers, dedicated appliances and 'managed service' systems which process all mail on their own systems before forwarding to customers.
Spam filters use a variety of techniques including analysing the origins of mail messages, parsing the content text and attachments and many other aspects of the email and its header information. Most filters allow the user to set up lists of known-good and known-bad senders (whitelists and blacklists) and also have systems for retrieving mails erroneously marked as spam.
