Internet very slow on a network

[system49]

For some reasons beyond me all computers on a windows 2000 server network with sp4 on all sytems is very slow in responding to website that one visits
It takes more than 2 minutes to be able to open websites
I have symantec antivirus corporate edition v10. I have installed all updates from microsoft website and have run trendmicro sypware tool on most of the machines but same problem
Any help

 

[franklin97355]

Is it faster when you are connected directly to the source?