Handling HTTP cookies is slightly more difficult than User-Agent and Referer since cookie headers are sent in both HTTP replies and requests. Cookies are sent to web browsers using the Set-Cookie HTTP header field and to web servers using the Cookie header. To filter both of these headers a filter must implement the RequestFilter and ReplyFilter interfaces. The resulting filter will have two filter() methods, one to remove Cookie from the Request object and the other to remove Set-Cookie from the Reply object.