Source: net2.com

Sometimes you may not want a server or daemon to start as part of the postinstall scrip when installing with apt-get or dpkg. To prevent servers from starting, do the following:

# Prevent launch of servers during apt-get install
mkdir -p /usr/sbin/
cat < /usr/sbin/policy-rc.d
#!/bin/sh
exit 101
EOF
chmod 755 /usr/sbin/policy-rc.d

When you are done, don’t forget to remove this file with:

rm -f /usr/sbin/policy-rc.d