Hello Mr. Thomas SHinder, tell me what to do. I have read your book "Configuring ISA Server 2000". This book is an exellent example of your experience & knowledge that Allah has given to you, but i am confused at a point that either you have not mentioned or i have no found the solution for configuring an unknown protocol to work connect an application to a dissemination server. Actually I have following problem I have an application that connects to our corporate database server so that clients can perform invetory as per official requirement, this application works well when the machine is directly connected to internet but fails to connect to dissemination server when the machine is behind ISA server. The application name is abc.exe and it connects to TCP port 5000-7000 with the server having IP 172.111.1.22. and domain xyz.com., How can I define a rule so that this application works behind isa server. By the if you have mentioned the concept in your book please reffer me to the page number. of if not please guide me what to do. Thanks and regards! M A Babur Kiani mab@xxxxxxxxxx