Free proxy sites software for linux

Proxy Detector is a PHP class that can detect HTTP requests via proxy. This class can detect if a visitor uses a proxy server by scanning the headers returned by the user client.
When the user uses a proxy server, most of the proxy servers alter the header. The header is returned to PHP in the array $_SERVER.
Enhancements:
- This is the first release of the class and implementation example.

Ircproxy is a transparent IRC content filtering application. It may be used whenever there is a need for monitoring IRC connections.

irc-proxy may be used to deny specific connections or to examine suspicious IRC traffic.

Proxy Applet is a GNOME tray applet for changing your network proxy configuration with a single click, in a manner similar to Galeon 1.x.
Galeon used to have a single click Network Proxy selector in their menu, which I used frequently. In a discussion with Epiphany developers about this same functionality (using GConf) they argued that you could already move the Proxy Network capplet to your taskbar.
But that doesnt offer all the functionality Im looking for. What I think would be neat is:
- An applet that gives you a list of preset configurations upon a single click.
- Each configuration is called a location and could either mean:
No proxy
Manually configured proxy
Proxy Auto Configuration (PAC)
A remote URL, eg. http://pac.isp.net/path/file.pac
A local URI, eg. file:///home/user/pacs/location.pac
- When you select another location, the applet should replace your GConf settings accordingly. (GConf key: /system/http_proxy)
- A preferences dialog should allow to manage locations and even test a location (see if proxy works or check PAC syntax ?).
- In a later phase there might even be an automatic selection based on eg. the network-configuration (ip-address, network, gateway, ??). So the applet has to monitor the network configuration for changes.
- When using tsocks or dante lib, we could have a dialog to socksify the complete system. (Add it to /etc/ld.so.preload or run /etc/init.d/tsocks)

Japt-Proxy is a JAVA based Caching Proxy for Debians APT-System. Japt-Proxy is very reliable and lightning fast. Japt-Proxy is usually used in environments where several Debian systems have to be kept up-to-date without downloading the same files over and over again from the debian mirrors. Mostly these environments are data centers, Linux-powered companies, schools, public authorities and so on.
Often Japt-Proxy is used because of small sized internet connections but it is also useful to install complete debian systems over the net (read: over the proxy). Even with high volume internet connections Japt-Proxy can dramatically reduce the time to install or update Debian on many machines.
Why Java?
I know there are people out there thinking "Hey? Why Java?". There are a bunch of reasons why people asking those questions. I have a simple answer to all those questions. The answer is, that Java enabled me to easily develop the fastest and most reliable APT-Proxy. Java and the Apache Software Foundation provides such good libraries for this job, that it wasnt very hard to bring up this tool.
If you dont trust, test it - the installation takes less than five minutes!
Doesnt a general proxy server supersede an APT-Proxy?
No, it doesnt. Japt-Proxy knows the characteristics of a Debian archive and their files. It knows, for example, that .deb files wont change, because newer files would have a new name (the version is always part of the filename), hence it wont recheck if there is a newer version of this specific file.
Furthermore you can configure the Japt-Proxy to delete old versions of a package in its cache directory - a general proxy cache would simple delete files that havent been requested for some time.
So, a general caching proxy like Squid is a perfect tool for caching "normal" internet traffic. If you need a proxy for faster APT access - Japt-Proxy is the right tool for you.
Main features:
- Caching of all apt requests from Debian archives
- Multi-threaded architecture which increases the download speed enormously when several machines are requesting packages
- Builds up a partial mirror directory automatically, with exactly the same directory structure and filenames as the original mirror
- Automatic and configurable cache cleanup (purging packages in cache if newer versions exists)
- Makes sources.list configuration easier for multiple machines - if you change your internet backend server you only have to make the change once in Japt-Proxy, instead of on all Debian machines
- Works with multiple architectures
- Backend support for HTTP and FTP
- existing .debs can be copied into the Japt-Proxy cache directory (from a CD or DVD for example) and will be used by the Proxy automatically

HTTP Proxy Client is the small set of libraries and scripts, which provides transparent access to Internet via HTTP proxy for programs, which uses TCP/IP for communication.
The list of programs includes: telnet, ftp, licq, cvs, smth else? Project implements dynamic library, that can be preloaded before program run.
The library substitutes some system calls (connect(), gethostbyaddr(), gethostbyname()), with calls, which makes TCP/IP connection through HTTP proxy. This allows client programs behind HTTP proxy work with Internet without limitations.
At the moment tested on i386 Linux, i386/sparc Solaris.
Enhancements:
- While using dotted address, applications will attempt to connect regardless DNS lookup result.

ftp.proxy is an application level gateway for FTP. It sits between a client and a server forwarding command and data streams supporting a subset of the file transfer protocol as described in RFC 959.
But, beside this basic function which makes the program useful on firewall or masqueraders it offers fixing the FTP server (e.g. for connections into a protected LAN) and proxy authentication.
Main features:
- ftp.proxy offers external access control programs (ACP), that is an external program decides if a user can use the proxy service or not. This decision can be made on username, host name, day of time etc.
- Since version 1.0.1 ftp.proxy supports also command control programs. Similar to ACPs the CCPs permit or deny access to certain FTP commands on the server, e.g. its possible to allow a user to get files but to deny any kind of uploads.

YAZ Proxy application is highly configurable and can be used in a number of different applications, ranging from debugging Z39.50-based applications and protecting overworked servers, to improving the performance of stateless WWW/Z39.50 gateways.
Main features:
- Configurable logging
- SRU/SRW server function, to allow any Z39.50 server to also support the ZiNG protocols
- Load balancing across multiple backend servers
- Session-sharing and pre-initialization to improve performance in servers with expensive session initialization
- Configurable request filtering, to keep bad requests from reaching the server
- XML support -- MARC records can be converted to MARCXML, and XSLT-transformations allow the proxy to support arbitrary retrieval schemas in XML
- Load governor function limits requests from aggressive batch-mode clients
- Efficient multiplexing software enables small memory footprint and very high performance
NOTE: The YAZ Proxy, a complete application, is available under the GPL license. Other licensing terms are available to commercial vendors upon request.