Hi all, It is near 6 months that I'm working on ISA Server and nearly read all of the articles in the ISAServer.org site, but there is still one problem I can?t solve. How can I force Firewall Service to ask unauthenticated users for credentials? (credTool.exe didn?t solve my exact problem) When a user logon to his local windows 2000 (not to the domain which his computer is a member of), he can still use Internet Explorer because IE will ask him for username and password, how can I do the same thing with a Firewall client who has a non-http request (for example is trying to use msn messenger)?