简述Linux Squid代理服务器的主要作用

squid is a high-performance proxy caching server for web clients, supporting FTP, gopher, and HTTP data objects. Unlike traditional caching software, squid handles all requests in a single, non-blocking, I/O-driven process.

squid keeps meta data and especially hot objects cached in RAM, caches DNS lookups, supports non-blocking DNS lookups, and implements negative caching of failed requests.

squid supports SSL, extensive access controls, and full request logging. By using the lightweight Internet Cache Protocol, squid caches can be arranged in a hierarchy or mesh for additional bandwidth savings.

squid consists of a main server program squid, a Domain Name System lookup program dnsserver, some optional programs for rewriting requests and performing authentication, and some management and client tools. When squid starts up, it spawns a configurable number of dnsserver processes, each of which can perform a single, blocking Domain Name System (DNS) lookup. This reduces the amount of time the cache waits for DNS lookups.

Linux中实现代理服务器功能最常用的软件为squid，下面是源代码包安装步骤：

1.从http://www.squid-cache.org下载squid-2.2.STABLE4-src.tar.gz

2.将该文件拷贝到/usr/local目录

cp squid-2.2.STABLE4-src.tar.gz /usr/local

3.解开该文件

tar xvzf

squid-2.2.STABLE4-src.tar.gz

#为了方便使用将目录更名为squid

mv squid-2.2.STABLE4 squid

4.进入squid目录   

cd squid

5.执行编译

./configure

#系统默认安装目录为/usr/local/squid

/configure -prefix=/directory/you/want

#指定安装目录

6.执行

make all

7.执行安装

make install

8.安装结束后，Squid的可执行文件在安装目录的bin子目录下，配置文件在etc子目录下。

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