A method and system for managing one or more web requests provided to a web application from a client computer. An application is responsive to a web request to generate verification data. The application sends a reply to the client to calculate a stamp as a function of the generated verification data. The application is responsive to an additional request from the client including the calculated stamp to determine if it corresponds to the generated verification data. If the calculated stamp corresponds to the generated verification data, the additional web request is submitted to the web application for processing. A Web server subject to a DOS attack will be able to distinguish between genuine users(who generate stamps) and malicious users(who will not generate stamps) and over a period of time be able to restore service to the former and deny to the latter.