Spambots usually create accounts and send spam messages with them. These spambots often use OCR technology to bypass CAPTCHAs present. The main purpose of a CAPTCHA system is to block spambots while allowing human users. Because email addresses have a distinctive format, such spambots are easy to code. As an SMTP server, Postfix implements a first layer of defense against spambots and malware. It is generally done by automated spambots. Automated spambots can rapidly make the user-editable portion of a site unusable. By accepting all authentic sender registration request, it is at least possible to eliminate spambots. People usually "Copy and Paste" or use spambots. A number of programs and approaches have been devised to foil spambots.