The current NTP standard. Available here in HTML, PDF, and Postscript formats.

The current standard for SNTP, a version of the protocol for implementations which do not need all of the features of NTP. Available here in HTML, PDF, and Postscript formats.

Aimed primarily at helping internal BNL.gov users with NTP, this page provides useful setup information for various flavors of Unix.

A discussion of why and how to set up NTP software. Some information is specific to the University, some is more general.

A tutorial on installing NTP servers on UNIX (OpenBSD and Linux) and Windows to accurately synchronize computer times.

NTP Project page for Dr. Mills, primary NTP researcher for over twenty years. He and his students are working on NTP version 4 to improve robustness and security.

NTP official reference implementation (for Unix and Unix-like OSes, with ports to Microsoft Windows NT, VMS, real-time OSes like VxWorks and QNX). Also jumping-off point to the official NTP documentation and FAQ, community documentation tools (twiki), pool.ntp.org, and related projects.

Sample chapter from the book, showing the cisco-specific methods of configuring your routers to support using NTP time synchronization.

Accurate timekeeping is vital to accurate records, and accurate logs are the mainstay of good system administration. Glenn Graham explains NTP (the Network Time Protocol) and how to put it to work on your network.

This book gathers hundreds of example router configurations all in one place. In chapter 14, the authors provide information on configuring, running, and debugging NTP on your Cisco router. This link via O'Reilly's Safari network for online publications.