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Squid is a caching and forwarding web proxy. It has a wide variety of uses, from speeding up a web server by caching repeated requests; to caching web, DNS and other computer network lookups for a group of people sharing network resources; to aiding security by filtering traffic. Although primarily used for HTTP and FTP, Squid includes limited support for several other protocols including TLS, SSL, Internet Gopher and HTTPS. Squid was originally designed to run as a daemon on Unix-like systems. A Windows port was maintained up to version 2.7. New versions available on Windows use Cygwin environment. Squid is free software released under the GNU General Public License. ==History== Squid was originally developed as the ''Harvest object cache'',〔C.Mic Bowman, Peter B. Danzig, Darren R. Hardy, Udi Manper, Michael F. Schwartz, The Harvest information discovery and access system, Computer Networks and ISDN Systems, Volume 28, Issues 1–2, December 1995, Pages 119-125. (doi:10.1016/0169-7552(95)00098-5 )〕 part of the Harvest project at the University of Colorado Boulder.〔(Squid intro ), on the Squid website〕〔(''Harvest cache now available as an "httpd accelerator"'' ), by Mike Schwartz on the http-wg mailing list, Tue, 4 April 1995, as forwarded by Brian Behlendorf to the Apache HTTP Server developers' mailing list〕 Further work on the program was completed at the University of California, San Diego and funded via two grants from the National Science Foundation. Duane Wessels forked the "last pre-commercial version of Harvest" and renamed it to Squid to avoid confusion with the commercial fork called Cached 2.0, which became NetCache.〔Duane Wessels (Squid and ICP: Past, Present, and Future ), Proceedings of the Australian Unix Users Group. September 1997, Brisbane, Australia〕 Squid version 1.0.0 was released in July 1996.〔 Squid is now developed almost exclusively through volunteer efforts. Web proxy caching is a way to store requested Internet objects (e.g. data like web pages) available via the HTTP, FTP, and Gopher protocols on a system closer to the requesting site. Web browsers can then use the local Squid cache as a proxy HTTP server, reducing access time as well as bandwidth consumption. This is often useful for Internet service providers to increase speed to their customers, and LANs that share an Internet connection. Because the caching servers are controlled by the web service operator, caching proxies do not anonymize the user and should not be confused with anonymizing proxies. A client program (e.g. browser) either has to specify explicitly the proxy server it wants to use (typical for ISP customers), or it could be using a proxy without any extra configuration: "transparent caching", in which case all outgoing HTTP requests are intercepted by Squid and all responses are cached. The latter is typically a corporate set-up (all clients are on the same LAN) and often introduces the privacy concerns mentioned above. Squid has some features that can help anonymize connections, such as disabling or changing specific header fields in a client's HTTP requests. Whether these are set, and what they are set to do, is up to the person who controls the computer running Squid. People requesting pages through a network which transparently uses Squid may not know whether this information is being logged.〔See the documentation for header_access and header_replace for further details.〕 Within UK organisations at least, users should be informed if computers or internet connections are being monitored.〔See, for example, (Computer Monitoring In The Workplace and Your Privacy )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Squid (software)」の詳細全文を読む スポンサード リンク
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