Polipo is a lightweight caching and forwarding web

proxy server In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource. Instead of connecting directly to a server that can fulfill a reques ...

. It has a wide variety of uses, from aiding security by filtering traffic; to caching web, DNS and other

computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...

lookups for a group of people sharing network resources; to speeding up a web server by caching repeated requests. It can be configured to use on-disk cache and serve cached content when offline and perform various forms of content filtering. To minimize latency, Polipo both pipelines multiple resource requests and multiplexes multiple transactions onto the same TCP/IP connection. Polipo is HTTP 1.1-compliant, supports IPv4,

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv ...

, traffic filtering and privacy-enhancement. Polipo is

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

released under the

MIT License The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...

. Polipo ceased to be maintained on 6 November 2016 due to the increasingly widespread use of encryption (i.e.

HTTPS Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network, and is widely used on the Internet. In HTTPS, the communication protocol is enc ...

) making caching proxies obsolete.

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, it has been put to uses such as a tether on the

OpenWrt OpenWrt (from ''open wireless router'') is an open-source project for embedded operating systems based on Linux, primarily used on embedded devices to route network traffic. The main components are Linux, util-linux, musl, and BusyBox. All ...

GUI wrappers

Natively, polipo comes as a highly specialized command-line interface (CLI) software application, which requires commands to be typed on the

keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Musi ...

and parameters stored in configuration text files. Alternatively, polipo allows users to run the program automated and non-interactively, such as in a shell script. By starting a GUI wrapper application users can intuitively interact with polipo, start and stop it and change its working parameters, through graphical

icon An icon () is a religious work of art, most commonly a painting, in the cultures of the Eastern Orthodox, Oriental Orthodox, and Catholic churches. They are not simply artworks; "an icon is a sacred image used in religious devotion". The most ...

s and visual indicators. Some independent GUI wrapper projects are: * Solipo - a GUI wrapper application for polipo on Windows * Dolipo - a GUI wrapper for OS X * Polipoid - a wrapper for Android

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 does HTTP 1.1 pipelining well, so it can enhance internet communication latency. * Polipo will make web browsing faster or at least appear to have 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, to some extent, substitute for filtering and privacy-enhancing proxies such as Privoxy or WWWOFFLE, it provides capabilities to block or redirect requests, censor HTTP request headers and referrer information. * 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 can speak the SOCKS 4 and SOCKS 5 protocols. * Polipo serves as a

web cache A Web cache (or HTTP cache) is a system for optimizing the World Wide Web. It is implemented both client-side and server-side. The caching of multimedias and other files can result in less overall delay when browsing the Web. Parts of the sys ...

Limitations

Polipo is limited to 2G or 4G file sizes on 32 bit systems which will cause errors when serving large requests.

References

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External links