Nginx.md

Nginx

Return client's IP

Use $remote_addr

location /ip {
   # disable cache
   expires -1;
   add_header 'Cache-Control' 'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0';

   default_type text/plain;
   return 200 "$remote_addr\n";
}

If you use the Cloudflare CDN, use $http_cf_connection_ip

location /ip {
   # disable cache
   expires -1;
   add_header 'Cache-Control' 'no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0';

   default_type text/plain;
   return 200 "$http_cf_connecting_ip\n";
}