软件简介
nginx（发音同 engine x）是一款轻量级的Web 服务器／反向代理服务器及电子邮件（IMAP/POP3）代理服务器，并在一个BSD-like 协议下发行。由俄罗斯的程序设计师Igor Sysoev所开发，最初供俄国大型的入口网站及搜寻引擎Rambler（俄文：Рамблер）使用。 其特点是占有内存少，并发能力强，事实上nginx的并发能力确实在同类型的网页伺服器中表现较好.
目前中国大陆使用nginx网站用户有：新浪、网易、腾讯,另外知名的微网志Plurk也使用nginx。
昨天刚刚发布《Nginx 0.9.0 开发版发布》 的消息后，Nginx 官方网站已经紧急发布了 Nginx 0.9.1 ,因为在 Nginx 0.9.0 发布不久之后就发现其中的一个 bug。不得不佩服 Nginx 官方修复软件漏洞的效率！我们建议大家不要在生产环境中把 Nginx 升级到最新的版本，因为一个开发版本远不如稳定版本安全可靠。
Nginx 0.9.1 修正了 Nginx 0.9.0 中 “return CODE message” 指命不能正常运行的 Bug。
Bugfix: “return CODE message” directives did not work; the bug had appeared in 0.9.0.
Changes with nginx 0.9.0 29 Nov 2010
*) Feature: the "keepalive_disable" directive.
*) Feature: the "map" directive supports variables as value of a defined variable.
*) Feature: the "map" directive supports empty strings as value of the first parameter.
*) Feature: the "map" directive supports expressions as the first parameter.
*) Feature: nginx(8) manual page. Thanks to Sergey Osokin.
*) Feature: Linux accept4() support. Thanks to Simon Liu.
*) Workaround: elimination of Linux linker warning about "sys_errlist" and "sys_nerr"; the warning had appeared in 0.8.35.
*) Bugfix: a segmentation fault might occur in a worker process, if the "auth_basic" directive was used. Thanks to Michail Laletin.
*) Bugfix: compatibility with ngx_http_eval_module; the bug had appeared in 0.8.42.