Free proxy software for linux

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newer files would have a new name (the version is always part of the filename), hence it wont recheck if there is a newer version of this specific file.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

Net::Proxy is a Perl framework for proxying network connections in many ways.

SYNOPSIS

use Net::Proxy;

# proxy connections from localhost:6789 to remotehost:9876
# using standard TCP connections
my $proxy = Net::Proxy->new(
{ in => { type => tcp, port => 6789 },
out => { type => tcp, host => remotehost, port => 9876 },
}
);

# register the proxy object
$proxy->register();

# and you can setup multiple proxies

# and now proxy connections indefinitely
Net::Proxy->mainloop();

A Net::Proxy object represents a proxy that accepts connections and then relays the data transfered between the source and the destination.

The goal of this module is to abstract the different methods used to connect from the proxy to the destination.
A proxy is a program that transfer data across a network boundary between a client and a server. Net::Proxy introduces the concept of "connectors" (implemented as Net::Proxy::Connector subclasses), which abstract the server part (connected to the client) and the client part (connected to the server) of the proxy.

This architecture makes it easy to implement specific techniques to cross a given network boundary, possibly by using a proxy on one side of the network fence, and a reverse-proxy on the other side of the fence.

rsh.proxy project is a proxy for rsh, rexec and rlogin.

About rsh

rsh (remote shell) is a command line computer program which can execute shell commands as another user, and on another computer across a computer network. The remote system on which the rsh executes the command needs to be running the rshd daemon. The rsh command shares the same name as another common UNIX utility, the restricted shell, which first appeared in PWB/UNIX; in System V Release 4, the restricted shell is often located at /usr/lib/rsh.

About rlogin

rlogin is a Unix software utility that allows users to log in on another host via a network, communicating via TCP port 513. It was first distributed as part of the 4.2BSD release. rlogin is also the name of the application layer protocol used by the software, part of the TCP/IP protocol suite. Logged-in users can act as if they were physically present at the computer.

IMAP Proxy server is a caching IMAP proxy server. It was written to compensate for webmail clients that are unable to maintain persistent connections to an IMAP server. Most webmail clients need to log in to an IMAP server for nearly every single transaction.

This behaviour can cause tragic performance problems on the IMAP server. imapproxy tries to deal with this problem by leaving server connections open for a short time after a webmail client logs out.

When the webmail client connects again, imapproxy will determine if theres a cached connection available and reuse it if possible.

How does imapproxy keep track of which server connection is for which user?

Upon the first successful login to the real IMAP server (through the proxy), imapproxy fills in a little record that contains the username, an md5 digital signature of the password and the server socket descriptor thats being used.

After you log out and then log back in again, imapproxy just has to find a record that matches your username and password. These records are stored in a hash table (with the username being the hash key) in memory, so the lookups are pretty fast.

Can IMAP Proxy support multiple backend servers?

If you want IMAP Proxy to be able to proxy to multiple backend IMAP servers, you can run multiple instances of IMAP Proxy and make sure each instance is looking at a different configuration file.

Before you do this, take a look at perdition which appears to have been designed with this specific task in mind.

Spike Proxy is an open source HTTP proxy for finding security flaws in web sites.

SPIKE Proxy is part of the Spike Application Testing Suite and supports automated SQL injection detection, web site crawling, login form brute forcing, overflow detection, and directory traversal detection.

To Use:

python spkproxy.py [ optional port argument, 8080 is default ]
Then set up your browser to use that port for both HTTP and
HTTPS proxies.

Then watch the traffic go!

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)

kproxyswitch is a simple bash script, which makes setting the proxy server easier. The setting applies to Konqueror and all other applications that use the global proxy setting.
If you have to change proxies from time to time - or switch the proxy off and on again.
Youll like the possibilty to bind this script to a keyboard/menu/... shortcut and thus be able to switch the proxy faster than going through the menus of Konqueror or KDE Control Center.
Enhancements:
- Small changes: added two apps (randr, nspluginviewer) to blacklist, made output more verbose.