阿里云多个二级域名，解析到同一个机器外网ip地址： 

http://demo.xxx.com.cn/

 http://yang.xxx.com.cn/

nginx.conf 配置文件：

server
    {
        listen 80;
        server_name yang.xxx.com.cn;# 第1个二级域名映射80端口
        index index.html index.htm index.php;
        root  /www/server/phpmyadmin-yang;

        #error_page   404   /404.html;
        include enable-php.conf;

        location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
        {
            expires      30d;
        }

        location ~ .*\.(js|css)?$
        {
            expires      12h;
        }

        location ~ /\.
        {
            deny all;
        }

        access_log  /www/wwwlogs/access.log;
    }
    
    server
    {
        listen 80;
        server_name demo.xxx.com.cn;# 第2个二级域名映射80端口
        index index.html index.htm index.php;
        root  /www/server/phpmyadmin-demo;

        #error_page   404   /404.html;
        include enable-php.conf;

        location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
        {
            expires      30d;
        }

        location ~ .*\.(js|css)?$
        {
            expires      12h;
        }

        location ~ /\.
        {
            deny all;
        }

        access_log  /www/wwwlogs/access.log;
    }