Definition " Low" & " High" in Destination Port

[#1]

Dear All, 1. I have Fortiget-100, i need to know what' s the mean of " Low" and " High" in Destination Port when configure Firewall => Service => Custom. Low - High = port range from low port number to high port number or Low = low priority High = High priority ?? 2. Then, when i want to block TCP port 665 (the port which curently being use by virus W32.Netsky.Z to spread), are my configuration below is correct? Source Port: Low = 1 High = 65535 Destination Port: Low = 1 High = 665 Thanks before

[#2]

Low, high is used to declare RANGE of ports. Some protocols start and end from specific ports to specific ports (or ranges of ports). A web brouser will use a port from 1024 to 65535 (source port) to conect only to port 80 (destination port). High and low is for this reason.

[#3]

You have the source port information correct, but your Destination information settings will block every port between 1 and 665. Change it to Low=665 and High=665, and you' ll only block port 665. Good luck -Eric Wall