Wie ermöglicht Nginx einem Server den Zugriff auf mehrere Websites?

#user nobody;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid    logs/nginx.pid;

events {
  worker_connections 1024;
}

##一个http节点
http {  
  include    mime.types;
  default_type application/octet-stream;
  #log_format main '$remote_addr - $remote_user [$time_local] "$request" '
  #         '$status $body_bytes_sent "$http_referer" '
  #         '"$http_user_agent" "$http_x_forwarded_for"';
  #access_log logs/access.log main;
  sendfile    on;
  #tcp_nopush   on;
  #keepalive_timeout 0;
  keepalive_timeout 65;
  #gzip on;
 #server 节点，即 你需要访问网站的配置
 #一个server节点，就是一个虚拟主机
  server {
    listen    80;  #监听的端口号，访问网站 默认是80端口
    server_name localhost;  #即访问的域名
    #charset koi8-r;
    #access_log logs/host.access.log main;
    location / {  #定位
      root  html;  #定位的是nginx根目录下的 html文件夹
      index index.html index.htm;  #设置网站首页
    }
  }
}

server {
    listen    81;
    server_name localhost;
    #charset koi8-r;
    #access_log logs/host.access.log main;
    location / {
      root  html-81;
  #nginx根目录下 新建的html81 文件夹
      index index.html index.htm;
    ``
  }