Home of the Network Time Protocol
- http://www.ntp.org/
- 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.
NTP Servers Web
- http://support.ntp.org/bin/view/Servers/WebHome
- Community maintained list of public Stratum 1 and Stratum 2 NTP time servers, including policies and requirements for use, contact information. Maintained via the NTP TWiki, by the admins of the respective sites themselves.
NTP Support Web
- http://support.ntp.org/bin/view/Support/WebHome
- Not the official NTP documentation or the official NTP FAQ. Intended to be the collection point for cookbook configurations, tips, hints, tricks, and other comments from directly from various members of the NTP community that might be beneficial to others within the community. Anyone who is interested in helping to develop or improve documentation for NTP is encouraged to join and contribute.
O'Reilly Cisco Cookbook
- http://safari.oreilly.com/0596003676
- 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.