代理服务器Squid

Squid cache（简称为Squid）是一个流行的自由软件（GNU通用公共许可证）的代理服务器和Web缓存服务器。Squid有广泛的用途，从作为网页服务器的前置cache服务器缓存相关请求来提高Web服务器的速度，到为一组人共享网络资源而缓存万维网，域名系统和其他网络搜索，到通过过滤流量帮助网络安全，到局域网通过代理上网。Squid主要设计用于在Unix一类系统运行。

Squid的发展历史相当悠久，功能也相当完善。除了HTTP外，对于FTP与HTTPS的支援也相当好，在3.0 测试版中也支援了IPv6。

《Squid中文权威指南》（http://home.arcor.de/pangj/squid/）

http://www.squid-cache.org/

Squid: Optimising Web Delivery

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. It reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator. It runs on most available operating systems, including Windows and is licensed under the GNU GPL.

Making the most of your Internet Connection

Squid is used by hundreds of Internet Providers world-wide to provide their users with the best possible web access. Squid optimises the data flow between client and server to improve performance and caches frequently-used content to save bandwidth. Squid can also route content requests to servers in a wide variety of ways to build cache server hierarchies which optimise network throughput.

Website Content Acceleration and Distribution

Thousands of web-sites around the Internet use Squid to drastically increase their content delivery. Squid can reduce your server load and improve delivery speeds to clients. Squid can also be used to deliver content from around the world - copying only the content being used, rather than inefficiently copying everything. Finally, Squid's advanced content routing configuration allows you to build content clusters to route and load balance requests via a variety of web servers.

 [The Squid systems] are currently running at a hit-rate of approximately 75%, effectively quadrupling the capacity of the Apache servers behind them. This is particularly noticeable when a large surge of traffic arrives directed to a particular page via a web link from another site, as the caching efficiency for that page will be nearly 100%.  - Wikimedia Deployment Information.

Want to learn more?

The Squid project provides a number of resources to assist users design, implement and support Squid installations. Please browse the Documentation and Support sections for more information.