David, I have packet filtering enabled but when things are working correctly and I ping our domain name I get a response from the right IP address (external interface on ISA Server) and people on the Internet are able to access our web page. But when the attack occurs nobody can access our web site by domain name (http://www.domain.com). CARLOS MAURICIO PEREZ C. Technical Support mauriciop@xxxxxxxxxxxx SoloSoft Ltda. -----Original Message----- From: David Dellanno [mailto:david@xxxxxxxxxx] Sent: Viernes 10 de Agosto de 2001 11:37 AM To: [ISAserver.org Discussion List] Subject: [isalist] RE: Urgent Help!!! IP spoofing attacks http://www.ISAserver.org If you have enabled 'Packet Filtering' the default packet filters that are installed with ISA are design to give you the result you mention ..."ping our website (ping www.domain.com) in that moment I get a response from an unknown IP address."