RFC1305 - Network Time Protocol (Version 3) The current NTP standard. Available here in HTML, PDF, and Postscript formats. http://www.faqs.org/rfcs/rfc1305.html

RFC2030 - Simple Network Time Protocol Version 4 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. http://www.faqs.org/rfcs/rfc2030.html

Network Time Protocol Version 3 Aimed primarily at helping internal BNL.gov users with NTP, this page provides useful setup information for various flavors of Unix. http://www.ccd.bnl.gov/xntp/

Network Time Protocol at the University of Michigan A discussion of why and how to set up NTP software. Some information is specific to the Unversity, some is more general. http://www.umich.edu/~rsug/services/ntp.html

Secure Network Time Protocol (stime) Information and drafts from the IETF Working Group pursuing authenticated distribution of time information. http://www.ietf.org/html.charters/stime-charter.html

Geodsoft How-To: NTP Time Synchronization A tutorial on installing NTP servers on UNIX (OpenBSD and Linux) and Windows to accurately synchronize computer times. http://geodsoft.com/howto/timesync/

Network Time Synchronization Project 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. http://www.eecis.udel.edu/~mills/ntp.html

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

O'Reilly Hardening Cisco Routers Sample chapter from the book, showing the cisco-specific methods of configuring your routers to support using NTP time synchronization. http://www.oreilly.com/catalog/hardcisco/chapter/ch10.html

LinuxDevCenter.com: Synchronizing Networks with NTP 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. http://www.linuxdevcenter.com/pub/a/linux/2003/01/02/ntp.html

O'Reilly Cisco Cookbook 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. http://safari.oreilly.com/?x=1&mode=toc&sortKey=title&sortOrder=asc&view=&xmlid=0-596-00367-6&g=&catid=&s=1&b=1&f=1&t=1&c=1&u=1&r=&o=1&n=1&d=1&p=1&srchText=#

Flawed Routers Flood University of Wisconsin Internet Time Server Report by Dave Plonka on the massive problems caused on the University of Wisconsin network and time servers, due to misconfiguration of NetGear equipment http://www.cs.wisc.edu/~plonka/netgear-sntp/

The NTP FAQ and HOWTO Understanding and using the Network Time Protocol (A first try on a non-technical Mini-HOWTO and FAQ on NTP) http://www.ntp.org/ntpfaq/NTP-a-faq.htm

Public NTP Time Server List Community maintained list of Stratum 1 and Stratum 2 NTP time servers, including policies and requirements for use, contact info, etc.... Maintained via the NTP TWiki, by the admins of the respective sites themselves. http://twiki.ntp.org/bin/view/Servers/WebHome

NTP Reference Implementation Mailing Lists Variety of mailing lists used to support ntp.org, including the announce list, CVS logs, bugs, and questions (which is gatewayed to the USENET newsgroup comp.protocols.time.ntp). http://mailman.ntp.org/mailman/listinfo

Vendor: Sun Blueprints Online: Using NTP to Control and Synchronize System Clocks - Part I: Introduction to NTP This article is the first of a series on the Network Time Protocol (NTP). NTP allows synchronizing clocks on different network nodes, which is critical in today's networked world. This first article provides an overview of why time synchronization is important and introduces basic NTP concepts. http://www.sun.com/blueprints/0701/NTP.pdf

Vendor: Sun Blueprints Online: Using NTP to Control and Synchronize System Clocks - Part II: Basic NTP Administration and Architecture This is Part 2 of a three-article series that discusses how to use Network Time Protocol (NTP) to synchronize system clocks. This article explains the basics of client and server administration, covering various client/server configurations, as well as authentication and access control mechanisms. This article also provides a number of suggestions for an effective NTP architecture. http://www.sun.com/blueprints/0801/NTPpt2.pdf

Vendor: Sun Blueprints Online: Using NTP to Control and Synchronize System Clocks - Part III: NTP Monitoring and Troubleshooting This article is the third in a series of three articles that discuss using Network Time Protocol (NTP) to synchronize system clocks. The goal of this article is to provide an effective understanding of NTP troubleshooting and monitoring. http://www.sun.com/blueprints/0901/NTPpt3.pdf

Vendor: Sun Blueprints Online: Using NTP on the Sun Fire 15K/12K Server This article addresses the time skew issues for the Sun Fire 12K/F15K server and explains how the system controllers and domains can be configured as NTP clients to external servers. A sample configuration is also provided. This article is targeted to the intermediate level of expertise. http://www.sun.com/blueprints/0603/817-2979.pdf

pool.ntp.org: The Internet Time Network Information on a collection of public NTP servers provided by users and ISP's placed in a DNS round-robin under pool.ntp.org. http://www.pool.ntp.org/