This URL filter can do 50,000 URL verifications/sec and can be used with the Squid Web proxy filter to block unwanted content.
It can enforce SafeSearch for all major search engines, block HTTPS proxy tunnels, blocks unauthorised VPNs, blocks UltraSurf et al., supports the YouTube edufilter, PhishTank URL list and enforces more secure usage of HTTPS. Some chat applications violate safe HTTPS usage and ufdbGuard detects the most popular chat protocols to be able to allow them without disabling HTTPS security features. ufdbGuard also produces statistics and has a reporting utility. ufdbguard installs from source of Redhat RPM package.