Hi CyberQuest, The problem with blocking P2P apps, like the dreaded Kazaa, is that they use methods to scan the firewall and find an available port. They will use a default port, but if that default port is not available, then it will use an alternate port. Kazaa will end up using TCP 80 if it can't access any other port. This makes it very difficult to whack Kazaa like apps because if they use an alternate port, other than TCP 80, you have to perform deep inspection of every packet going outbound through the firewall. There are products that do just this, like the Akonix L7 for ISA Server solution. On the other hand, if you restrict your users to just TCP 80 and use ISA Server 2004 advanced HTTP security filter, you can check the HTTP headers and block the connections that contain the P2P headers. I've done this already with ISA Server 2004 and it works a treat! The drawback is the users who you want to block in this way must be restricted to HTTP *only*. HTH, Tom Thomas W Shinder www.isaserver.org/shinder ISA 2004 Beta - Get it now! http://www.microsoft.com/isaserver/beta/default.asp ISA Server and Beyond: http://tinyurl.com/1jq1 Configuring ISA Server: http://tinyurl.com/1llp -----Original Message----- From: Cyber quest [mailto:cyberquests@xxxxxxxxxxx] Sent: Wednesday, May 12, 2004 6:35 AM To: [ISAserver.org Discussion List] Subject: [isalist] RE: Firewall Client Problem http://www.ISAserver.org Well At last u got my point yeah u can say i aam an ISP but isnt there any method using ISA to block these softwares i mean cant i block all these acceletors and p2p softwares ? Help STOP spam with the new MSN 8 and get 2 months FREE* ------------------------------------------------------ List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ ------------------------------------------------------ Other Internet Software Marketing Sites: Leading Network Software Directory: http://www.serverfiles.com No.1 Exchange Server Resource Site: http://www.msexchange.org Windows Security Resource Site: http://www.windowsecurity.com/ Network Security Library: http://www.secinf.net/ Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com ------------------------------------------------------ You are currently subscribed to this ISAserver.org Discussion List as: tshinder@xxxxxxxxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')