location / {
                auth_request /auth;
		# ...
        }

        location = /auth {
                proxy_pass http://127.0.0.1:8080/auth;
                proxy_pass_request_body off;
                proxy_set_header Content-Length "";
                proxy_set_header X-LDAP-Auth-Server "dc_server_list";
                proxy_set_header X-LDAP-Auth-Prefix "";
                proxy_set_header X-LDAP-Auth-Suffix "@DOMAIN.local";
        }