Dante is a free implementation of the proxy protocols SOCKS version 4 and SOCKS version 5 (RFC 1928). It can be used as a firewall between networks, controlling outgoing traffic. The package consists of two parts: a socks server and a proxy client that supports socks, HTTP proxies, and UPnP. RFC 1961 (GSSAPI) is supported in both the client and the server. Commercial support is available.
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.
Frox is a transparent FTP proxy that runs under Linux and *BSD. It should also work on other UNIX OSes that use ipfilter. It supports caching of FTP downloads, either by redirecting through a Squid proxy, or through its own local cache. Downloads may also be transparently scanned for viruses (through an external scanner). Additionally there is an interface for writing scripts to add features or modify frox's behavior, and examples are included to limit download file size and to transparently direct connections to specific hosts to mirror servers. The proxy is written with security in mind, and in the default setup runs as a non-root user in a chroot jail.
HTTPGate is a filtering HTTP Gateway originally intended to enchange user's privacy when surfing on the net, but it can also be used to avoid censorware systems in web browsing. HTTPGate operates on a user definable internet port where the user connects using a web browser. The main page shows a text box and a set of options user can choose to avoid transmitting some information during client/server negotiation.
httpMonitor is a Python program which lets you monitor the HTTP traffic between a browser and a Web server. You configure your browser to use httpMonitor as its proxy to ensure that all HTTP traffic between browser and server goes via httpMonitor. In a XML-configuration file you can specify a Python-function as processor for the HTTP-messages you are interested in (requests or responses, which match certain criteria). You may have as many processors as you want, without modifying the actual program. The only thing you need to do is configure the httpMonitor and write your processors.
jftpgw is a proxy server for the FTP protocol. It is highly configurable, allowing you to use an XML-like configuration file to define almost any combination of the client's IP, the server's IP, the user name, the destination port, and so on. jftpgw supports inetd/daemon mode, transparent proxying, forwards, caching, logging, data IP and port specification (port ranges), limiting of the number of simultaeous sessions, and several proxy login styles for clients that support FTP proxies.
Jonama is a piece of software acting as a relay between a client over the Net and your internal systems. It was developed which security in mind, ie. it makes use of the SSL protocol to identify remotes and crypt channels and uses Unix mechanisms like chroot and setuid to minimize rights and actions.