This is new to Vista as XP works fine. When you simply set append Primary DNS suffix, the system should always append it, such that is your domain is mydomain.com, and you look up www, it should append so the FQDN=www.mydomian.com That seems to work fine, but if you do one more deep, such as www.test, you would expect as in XP and in DNS in general to append the primary suffix, such that the FQDN