nginx限制IP访问网站

需求：网站只允许指定IP访问，其他访问一律拒绝
server
{
listen 80;
server_name a.com;
index index.html index.htm index.php;
root /var/wwwroot/aaa/;
allow 23.100.1.222;
allow 23.107.17.58;
allow 23.107.17.59;
allow 23.107.17.60;
allow 23.107.17.61;
allow 23.107.17.62;
deny all;