Thanks for the reply but it was very disappointing, do you mean that I can?t use ISA for non-http request when I'm not logged on to my network? As a matter of fact my main problem is authenticating user of other domains, I mean here we have 10 domains, which are physically connected and have IPs in a same class but one domain is the main domain. So everybody has an account in this main domain and Internet access is allowed based on this accounts. When users of those 9 other domains want to use Internet they should enter the credentials of their account on the main domain, but what about their non-http request? Do you mean that there is no ways to let these users get authenticated by credentials other than those that they login with?