The quick and dirty way to set up an NTP server on Debian Linux for your network.
This has been tested using Debian 7.0 "Wheezy".
1. Install NTP server:
apt-get install ntp
2. Edit /etc/ntp.conf: add the networks that are allowed to sync with your time server like so (Adjust parameters accordingly.):
restrict 192.168.0.0 mask 255.255.255.0 nomodify notrap
3. Restart the NTP service:
4. Set your device/computer/server to use your NTP server