Ffproxy is a filtering HTTP/HTTPS proxy server. - It is able to filter by host, URL, and header. - Custom header entries can be filtered and added. - It can even drop its privileges and be chrooted. - Logging to syslog() is supported. - It can use another auxiliary proxy server. - HTTP accelerator feature (acting as front-end to a HTTP server) is included. - It allows transparent IPv6 over IPv4 browsing (and vice versa).