$ sudo mkdir /etc/nginx/vhost

$ sudo vi /etc/nginx/vhost/vhost_siteA.conf

server {
  listen    80;            # 监听端口
  server_name www.siteA.com siteA.com;  # 站点域名
  root /home/user/www/blog;       # 站点根目录
  index index.html index.htm index.php;  # 默认导航页
 
  location / {
    # WordPress固定链接URL重写
    if (!-e $request_filename) {
      rewrite (.*) /index.php;
    }
  }
 
  # PHP配置
  location ~ \.php$ {
    fastcgi_pass unix:/var/run/php5-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
  }
}

$ sudo vi /etc/nginx/vhost/vhost_siteB.conf

server {
  ...
  server_name www.siteB.com siteB.com;  # 站点域名
  root /home/user/www/forum;       # 站点根目录
  ...
}

sudo vi /etc/nginx/nginx.conf

http {
  ...
  include /etc/nginx/vhost/*.conf;
}

$ sudo service nginx restart

$ sudo cp /etc/nginx/sites-available/default /etc/nginx/sites-available/default_bak
$ sudo vi /etc/nginx/sites-available/default

server {
  listen 80 default_server;
  server_name _;
  return 404;
}

location ^~ /blog/ {
  deny all;
}
location ^~ /forum/ {
  deny all;
}