使用CDN后 NGINX 获取访问用户的真实 IP

http
    {
    …
    log_format  main  '$http_x_forwarded_for - $remote_user [$time_local] "$request" ' 
                    '$status $body_bytes_sent "$http_referer" ' 
                   '"$http_user_agent" ';
    …        

server
    {
        …
        set_real_ip_from 127.0.0.1; #服务器本地
        real_ip_header    X-Forwarded-For;
        real_ip_recursive on;
        …
    }