nginx防止域名恶意解析，就是要关闭默认站点：
server{
    listen 80 default_server;
    listen 443 ssl default_server；
    listen [::]:80 default_server;
    listen [::]:443 ssl default_server;
    server_name _;
    ssl_certificate /usr/share/nginx/a.pem;
    ssl_certificate_key /usr/share/nginx/a.key;
    return 444;
}