DeleGate is a multi-purpose application level gateway or proxy server that mediates communication of various protocols, applying cache and conversion for mediated data, controlling access from clients, and routing toward servers. It translates protocols between clients and servers, converting between IPv4 and IPv6, applying SSL (TLS) to arbitrary protocols, merging several servers into a single server view with aliasing and filtering. It can be used as a simple origin server for some protocols (HTTP, FTP, and NNTP).
FilterProxy is a Perl script that acts as a generic Web proxy. It is unique in that it allows you to install modules that can perform arbitrary transformations on HTML (or any other MIME-type) and HTTP headers. It filters ads by stripping HTML from the page, anonymizes requests by removing Referer and User-Agent headers, compresses HTML content, and de-animates animated gifs. Configuration is done via Web-based forms or editing a Perl data structure.
RabbIt is a mutating, caching Web proxy used to speed up surfing over slow links like modems. It does this by removing advertising and background images and scaling down images to low quality JPEGs. RabbIT is written in Java and should be able to run on any platform. It does depend upon an image converter if image scaling is on. The recommended image converter is "convert" from the ImageMagick package.
The WWWOFFLE programs simplify World Wide Web browsing from computers that use intermittent (dialup) connections to the Internet. It is a simple proxy server with special features for use with dial-up Internet links. It makes it possible to browse Web pages and read them without having to remain connected. There are too many features to mention, but they include privacy control, cookie/advert blocking, efficient bandwidth usage by specifying intervals between refreshes, options to monitor pages regularly, recursive fetching, HTML cleaning, highlighting of cached links, indexes of cached pages, searching of cached pages, and many more.
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 optionally chroot() to some directory. Logging to syslog() is supported, as is using another auxiliary proxy server. An HTTP accelerator feature (acting as a front-end to an HTTP server) is included. Contacting IPv6 servers as well as binding to IPv6 is supported and allows transparent IPv6 over IPv4 browsing (and vice versa).
PHP-Proxy is a PHP script for taking Web pages from one server, so that your main server is protected if the Web server is overloaded from things like DOS attacks. It is also very useful if you have a machine behind a firewall that you want to be your server for Web pages, provided that the machine running the proxy has port 80 open. Finally, there is encryption to defeat filters on specific words if need be.
NatACL is a Linux firewall group policy controller for intranets and Internet. Using a internal DHCP server, it can force users to use a DHCP client, and you can block static IPs. It will bind an IP to a MAC address and enforce this usage. You can control groups that can see each other with intranet policies, or control who has access to the Internet. It also has an option to force users to authenticate themselves over the Web before accessing the Internet.