In Debian GNU/Linux, one can find start/stop scripts for services in /etc/init.d. Common examples include crond, ssh, and gpm. One can configure a service to start or not at boot using update-rc.d, or by manipulating symlinks found in /etc/rcN.d (N = run level). See the file README in /etc/init.d in your Debian system, and read update-rc.d(8).
For example, to keep SSH from starting on boot, do
# update-rc.d -f sshd remove
To make sshd start at boot in run levels 2, 3, 4, and 5 (sequence 30) and stop in run levels 0, 1, and 6 (sequence 20), do
# update-rc.d ssh start 30 2 3 4 5 . stop 20 0 1 6.
Referensi : http://nmglug.org/tutorials_os.html#services-deb