Hi, I wish to authenticate (NTLM) our users only once per working day: authenticate_ip_shortcircuit_ttl 8 hours When the user browses for the first time, he will be authenticated and his IP will be cached so that, for the next 8 hours, Squid believes that requests coming from this IP belong to that user. Now comes the tricky part: if that user logs off and somebody else logs in before those 8 hours expire, Squid would mistakenly associate the same IP with the previous identity. As our IE browsers are pre-configured with a standard home page, and the new user couldn't avoid opening it before being able to go elsewhere, I tried enforcing (re)authentication for the home page: acl HOME_PAGE url_regex -i homepage.intranet authenticate_ip_shortcircuit_access deny HOME_PAGE It didn't work. Does authenticate_ip_shortcircuit_access accept only IP acl's ?