diff --git a/debian.cfg b/debian.cfg
index 55f4460..700ff6d 100644
--- a/debian.cfg
+++ b/debian.cfg
@@ -1,3 +1,4 @@
+# https://www.debian.org/releases/stable/amd64/apbs04.zh-cn.html
 # B.4.1. 本地化
 d-i debian-installer/locale string en_US
 d-i keyboard-configuration/xkb-keymap select us
@@ -59,7 +60,7 @@ d-i finish-install/reboot_in_progress note
 
 # B.5.1. 安装过程中运行用户命令
 d-i preseed/early_command string \
-  wget https://geoip.fedoraproject.org/city -O - | grep -w CHN && hostname=ftp.cn.debian.org || hostname=deb.debian.org; \
+  wget http://www.cloudflare.com/cdn-cgi/trace -O- | grep -x 'loc=CN' && hostname=ftp.cn.debian.org || hostname=deb.debian.org; \
   debconf-set mirror/http/hostname $hostname
 
 d-i partman/early_command string \