In a debian server, when I tried to add nagios service to startup, it appeared this error:
update-rc.d: using dependency based boot sequencing
update-rc.d: error: nagios Default-Start contains no runlevels, aborting.
To fix only add the next two lines on /etc/init.d/nagios between "### BEGIN INIT INFO"
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
