A denial of service flaw in the way TCP connections are maintained when receiving a zero byte receive window has been discussed. This flaw allows an attacker (the receiver) to consistently advertise a zero byte receive window, instructing the sender to maintain the TCP connection and probe the receiver until the receiver is ready to receive data. This is referred to as the TCP persist condition. This can cause the sender to consume system resources, eventually leading to a denial of service. For more information, please see our knowledgebase article: http://kbase.redhat.com/faq/docs/DOC-21623