I installed Wheezy + ispconfig 3 following this guide : www.howtoforge.com/perfect-server-ubuntu-12.10-apache2-bind-dovecot-ispconfig-3 I installed munin following this guide : http://www.howtoforge.com/server-monitoring-with-munin-and-monit-on-debian-squeeze I don't have any NTP graphs in Munin, all other graphs works.