diff --git a/fstest/testserver/init.d/TestSMBKerberos b/fstest/testserver/init.d/TestSMBKerberos
index 78a03868a..f54eeb6e5 100755
--- a/fstest/testserver/init.d/TestSMBKerberos
+++ b/fstest/testserver/init.d/TestSMBKerberos
@@ -37,6 +37,8 @@ RUN rm -rf /etc/samba/smb.conf /var/lib/samba \
  && samba-tool user setexpiry $USER --noexpiry \
  && mkdir -m 777 /share /rclone \
  && cat <<EOS >> /etc/samba/smb.conf
+[global]
+server signing = auto
 [public]
 path = /share
 browseable = yes