server_name指令可以设置基于域名的虚拟主机，根据请求头部的内容，一个ip的服务器可以配置多个域名。下面这些server_name的参数是有效的:
server_name jb51.net;
server_name jb51.net www.jb51.net;
server_name *.jb51.net;
server_name .jb51.net;
server_name nginx.*;
server_name jb51.netg bucknell.net brackley.org;
server_name localhost litchfield bleddington;
s
