 |
|
| Recent
Articles |
Howto Backup Your Mac Incrementally Over SSH
Do you have access to a shell account on a unix server with some spare space? If so it's pretty easy to incrementally backup your files securely with SSH. I titled this entry Howto Backup your Mac incrementally over...
Background Tasks (Why?)
A comp.unix.shell newsgroup post asked a neophyte question about how to run a script in the background.The terse answer was, of course,
script &. While perfectly correct, that leaves out so much. I started to write...
GoboLinux - A Breath Of Fresh Air?
My very first reaction to GoboLinux was negative. The underlying idea of taming the Unix/Linux file system hierarchy with symbolic links isn't new: heck, SCO did that way back with their 3.2v4.0 release, and for exactly...
The Influence Of Unix On NT
For several years now I've been looking for something Bill Gates said. Unfortunately I had misremembered the actual words, and every time I found someone who thought they remembered it, they had the wrong...
More Reasons To Love Unix/Linux
I did a lot of clean-up work at this website over the long Thanksgiving weekend. This was all due to radically changing the layout. Some of that was quick and simple do do, but for older pages I needed to do some...
The 15 Commands Essential for Unix
Learning UNIX is a seemingly daunting task, there are thousands of commands out there, each with hundreds of options. But in reality you only need to know a few of them. I use unix quite a bit, usually either on ...
Reconsidering The Value Of OSS Indemnification
With Microsoft agreeing not to sue Novell SLES Support Subscription customers for patent infringement issues, maybe it's time to reconsider the value of OSS indemnification? I've stated previously that...
Vi in a Nutshell
The unix text editor vi probably has more features than Microsoft Word yet I've only been using about 5 of them. Recently I've been learning a bit more about it. I now know some of the more handy features thanks to...
|
|
|
02.13.07
Configuring A Linux NTP Server
 By
Dave Evans
Network Time Protocol (NTP) provides algorithms and defines messages for the synchronisation of time clients to an accurate time reference.
This article discusses how to configure a Linux NTP Time Server to synchronise time with an Internet based public NTP Server.
NTP server systems fall into two categories: primary reference servers and secondary reference servers. Primary reference servers use an external timing reference to provide time, such as GPS or radio clocks. Secondary reference servers synchronise with primary reference NTP servers and offer slightly reduced accuracy. Primary reference servers are designated stratum 1 servers, while secondary servers have a stratum greater than 1.
The NTP Distribution
The NTP source code is freely available from the Network Time Protocol web site. The current version available for download is 4.2.4. NTP is available for the Linux operating systems with ports available for Windows NT. Once the source code is downloaded, it should be configured, compiled and installed on the host machine. Many Linux operating systems, such as RedHat, offer NTP RPM packages.
Configuring NTP
The 'ntp.conf' file is main source of configuration information for a NTP server installation. Amongst other things, it contains a list of reference clocks that the installation is to synchronise. A list of NTP server references is specified with the 'server' configuration command thus:
server time-a.nist.gov # NIST, Gaithersburg, Maryland NTP server server time-c.timefreq.bldrdoc.gov # NIST, Boulder, Colorado NTP server
Controlling the NTP Server Daemon
Once configured, the NTP daemon can be started, stopped and restarted using the commands: 'ntpd start'; 'ntpd stop' and 'ntpd restart'. The NTP server daemon can be queried using the 'ntpq -p' command. The ntpq command queries the NTP server for synchronisation status and provides a list of servers with synchronisation information for each server.
NTP Access Control
Access to the NTP server can be restricted using the 'restrict' directive in the ntp.conf file. You can restrict all access to the NTP server with:
restrict default ignore
Continue reading this article.
About the Author:
Dave Evans develops Linux NTP Server synchronisation systems to ensure accurate time on PC's and computer networks. Find out more about Linux NTP Time Server systems at: http://www.timetools.co.uk/ntp-servers/ntp-server-s5000.htm
|
