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	Issue TOC Print full article Print this page Download as PDF E-Mail this URL Discuss this article Flame the author     In this article Introduction Setting Your NTP Time Model Step by Step

1. Download the production Unix tarball and patches. Those are available from www.ntp.org/downloads.html.

2. Unzip and untar the archive. Follow the directions in the readme file to compile and install the programs.

3. Get a list of public time servers on the Internet (www.eecis.udel.edu/~mills/ntp/servers.html). Follow the access policies of the public servers located here.

4. Use traceroute (tracert on Windows) to locate time servers on the Internet that are close to your time servers. That will ensure the shortest round-trip time or fewest number of hops (usually the same thing).

5. Enter the time servers in /etc/ntp.conf. Use multiple servers for greater reliability. Use the "prefer" keyword to select a preferred time server.

6. Start the NTP daemon. To check if the daemon is running, use the ntpq utility and enter "pe." If NTP is working properly, you'll see output for your peers that looks like the graphic on the left.

Chart click to enlarge

7. Wait for the NTP daemon to synchronize. If you're in a big hurry, fire up packet sniffing using tcpdump udp Port 123 and look for traffic to and from your NTP peers. If you don't see traffic to and from the NTP servers, there could be several reasons for the failure, such as no domain-name resolution or firewall problems.