ufdbGuard is a URL filter. The URL filter blocks access to sets of Web sites and cooperates with the Squid proxy. It integrates with LDAP, Kerberos, Active Directory, MySQL, and others to define different ploicies for different groups of users. ufdbGuard also enforces SafeSearch for many search engines, blocks Skype, UltraSurf, Tor, unsafe HTTPS sites, and dynamically detects proxy tunnels. The multi-threaded daemon uses a fast algorithm that does 50,000 URL verifications per second on an Intel Core 2 Duo (Conroe) at 2.4 GHz.