Dear Tony, When you install isa server you creat a rule for access the internet and other application through isa server and I think you made that rule for all user for all application. First you have to delete that rule and when you creating new rule please do not select all protocols you have to select which protocol you want. When you completed this client will not use Yahoo messenger and other application that you have not selected in the rule. Hope this will solve your problem. Muzaffar Khan