Polipo
Encyclopedia
Polipo is a fast and lightweight, forwarding and caching proxy server
Proxy server
In computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
and computer software daemon
Daemon (computer software)
In Unix and other multitasking computer operating systems, a daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user...
.
By virtue of being a compliant HTTP 1.1 proxy, Polipo has all the uses of traditional Web proxies. It features HTTP 1.1, IPv4
IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
& IPv6
IPv6
Internet Protocol version 6 is a version of the Internet Protocol . It is designed to succeed the Internet Protocol version 4...
, traffic filtering and privacy-enhancement. Polipo supports HTTP 1.1 pipelining
HTTP pipelining
HTTP pipelining is a technique in which multiple HTTP requests are sent on a single HTTP connection without waiting for the corresponding responses....
and simulating multiplexing
Multiplexing
The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...
, (referred to as poor man's multiplexing
Time-division multiplexing
Time-division multiplexing is a type of digital multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as sub-channels in one communication channel, but are physically taking turns on the channel. The time domain is divided into several recurrent...
). by interleaving multiple segments to reduce communication latency.
Polipo is free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
, "and comes with absolutely no strings attached". It runs on GNU
GNU
GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...
/Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
, OpenWrt
OpenWrt
OpenWrt is a Linux distribution primarily targeted at routing on embedded devices. It comprises a set of about 2000 software packages, installed and uninstalled via the opkg package management system. OpenWrt can be configured using the command-line interface of BusyBox ash, or the web interface...
, Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
, Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
, and FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
. Almost any Web browser can use it.
Inherent design
Polipo is designed to be used as a personal web cache or a web cache shared among a few users to boost internet access. Designed to be fast, lightweight and small, it is useful when the system resources for a larger proxy are unavailable. Because of this reason, it has been put to uses such as a tether on the OpenWrtOpenWrt
OpenWrt is a Linux distribution primarily targeted at routing on embedded devices. It comprises a set of about 2000 software packages, installed and uninstalled via the opkg package management system. OpenWrt can be configured using the command-line interface of BusyBox ash, or the web interface...
.
Features
The fast, lightweight and small memory footprint proxy server polipo uses a variety of techniques:- Polipo will upgrade client requests to HTTP/1.1 even if they come in as old HTTP/1.0.
- Polipo will make web browsing faster or at least appear to be of less latency.
- Polipo will cache the initial segment of a download and can complete it later using Range requests, in case of interrupts.
- Polipo can substitute filtering, privacy-enhancing proxies such as PrivoxyPrivoxyPrivoxy is a non-caching web proxy with filtering capabilities for enhancing privacy, modifying web page data and HTTP headers before the page is rendered by the browser. Privoxy is a "privacy enhancing proxy", filtering Web pages and removing advertisements...
or WWWOFFLEWWWOFFLEWWWOFFLE is a proxy server and web caching software, allowing dial-up or broadband users to cache data for offline use. It can handle HTTP, HTTPS, FTP, and finger protocol, and operates on IPv4 and IPv6. Version builds are Unix-based: ports are available for Linux, and Win32 support is provided via...
. - Polipo has complete support for IPv6.
- Since Polipo can speak both IPv4 and IPv6, Polipo can be used as a bridge between the IPv4 and IPv6 Internets.
- Polipo acts as a content-filteringContent filteringContent filtering is the technique whereby content is blocked or allowed based on analysis of its content, rather than its source or other criteria. It is most widely used on the internet to filter email and web access.- Content filtering of email :...
by means to deny access to URLs specified in a blacklistBlacklist (computing)In computing, a blacklist or block list is a basic access control mechanism that allows everyone access, except for the members of the black list . The opposite is a whitelist, which means allow nobody, except members of the white list...
. - Polipo acts as a privacy-enhancing web proxy server which provides control over the content that may be relayed through the proxy.
censoredHeaders = OPTION1,OPTION2,OPTION3,...
censorReferer = true|false|maybe
- Polipo can speak the SOCKS 4 & SOCKS 5 protocolsSOCKSSOCKS is an Internet protocol that routes network packets between a client and server through a proxy server. SOCKS5 additionally provides authentication so only authorized users may access a server...
. - Polipo does HTTP 1.1 pipelining well, so it can enhance internet communication latency.
- Polipo serves as a web cacheWeb cacheA web cache is a mechanism for the temporary storage of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag...
.
Polipo and the anonymising proxy server TOR
Polipo can speak the SOCKS 4 & SOCKS 5 protocolsSOCKS
SOCKS is an Internet protocol that routes network packets between a client and server through a proxy server. SOCKS5 additionally provides authentication so only authorized users may access a server...
and therefore is recommended to be used together with the TOR
Tor (anonymity network)
Tor is a system intended to enable online anonymity. Tor client software routes Internet traffic through a worldwide volunteer network of servers in order to conceal a user's location or usage from someone conducting network surveillance or traffic analysis...
anonymising network. Polipo is a web proxy that does HTTP 1.1 pipelining well, so it can enhance TOR's communication latency or lag.
See also
- Web acceleratorWeb acceleratorA web accelerator is a proxy server that reduces web site access times. They can be a self-contained hardware appliance or installable software....
which discusses host-based HTTP acceleration - Proxy serverProxy serverIn computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
which discusses client-side proxies - Reverse proxyReverse proxyIn computer networks, a reverse proxy is a type of proxy server that retrieves resources on behalf of a client from one or more servers. These resources are then returned to the client as though it originated from the reverse proxy itself...
which discusses origin-side proxies - Comparison of web serversComparison of web servers-Overview:-Features:- Operating system support :...
- Comparison of lightweight web serversComparison of lightweight web serversLightweight web servers are web servers which have been designed to run with very small resource overhead because of hardware, environment, or simply for the challenge of it....
- Internet Cache ProtocolInternet Cache ProtocolThe Internet Cache Protocol is a protocol used for coordinating web caches. Its purpose is to find out the most appropriate location to retrieve a requested object from in the situation where multiple caches are in use at a single site...