Offers web caching, firewall, mail server, access control and activity logging. [Windows]

Open source web proxy designed to help Internet users affected by Internet censorship securely bypass content-filtering systems. Its recommended use is amongst private, trusted relationships rather than as an open public proxy.

Offers connection sharing, bandwidth throttling and realtime graphical and data analysis of proxied traffic. Supports HTTP, FTP and POP3 traffic. [Windows]

Offers a NAT firewall, transparent proxy, secure email server, access control policies, user monitoring, VPN, and reverse proxy. Content filtering and anti-virus plug-ins available. [Windows]

Forwarding, non-caching, HTTP proxy targeted for traffic optimization. This open source application works by compressing pictures and other data.[UNIX]

Offers connection sharing, monitoring and user level access control. Also offers http, email, ftp and news server functionality. [Windows]

ComTun Pro, offers connection sharing, firewall, spam filtering and caching. [Windows]

HTTP/HTTPS proxy that runs from inetd, and uses less than 1kb of diskspace. [Unix]

Filtering HTTP proxy that rewrites the HTML of the web pages that pass through it; removing unwanted/hostile content from the pages and providing enhanced user anonymity. [Written in PHP, platform independent]

HTTP proxy that enhances user privacy by deleting (or faking) eight data elements, including the Cookie field and Referrer fields, from web browser responses. [Windows]