A spam filter is a piece of software that’s installed on a mail server and keeps track of all incoming messages to block any unwelcome ones from entering a specific mailbox. Several examples of such email messages would be: offers for pills or money, fake bank statements or email attachments that contain malicious code sent with the idea to infect your personal computer. Email filters normally ‘scan’ the content of an email and in case they spot specific keywords or other dubious content, they either erase the email message or deliver it to the Spam/Junk folder instead of the Inbox folder. Some hosting companies combine their own email filters with up-to-date databases from spam-monitoring organizations, so as to ensure higher levels of security for their clients. Such databases include patterns, mail server IPs and other information about spam messages recently revealed by these organizations.