A friend asked me today: what are the pros and cons of chronyd and ntpd? I've used both for a while, but never actually sat down to think about this question. So here are some initial thoughts: ntpd (the older of the two implementations): has had...
NTP: a behind-the-scenes protocol As I've mentioned before, Network Time Protocol is one of those oft-ignored-but-nonetheless-essential subsystems which is largely unknown, except to a select few. Those who know it well generally fall into the...
Last week I was privileged to be sponsored by the Network Time Foundation to give a talk at AusNOG 2017. The slides are now available on the conference site (and here, too). The talk covers some of the operational issues which NTP has faced over...
I recently wanted to look at some packet captures on my NTP pool servers and find out if any NTP clients hitting my servers use extension fields or legacy MACs. Because the overall number of NTP packets is quite large, I didn't want to spool all...
Yesterday I updated NTPmon to include telegraf support; if you are interested in the code changes see github compare for details. It should be considered alpha-quality at this stage; it communicates with telegraf using the TCP or socket listener,...
I presented my talk based on the blog posts here at Linux.conf.au 2017; thanks to everyone who responded - your feedback is appreciated. Here are some links for anyone who's interested: Talk slides Youtube video Downloadable video There won't be...
In this post, I'm going to address some of the more common myths about NTP and how to avoid the mistakes which they produce. Some of these myths are grounded in fact, and in many cases it's fine to accept them if you don't need highly accurate...
(See the menu for other posts in this series.) Am I in sync? So now that we've configured NTP, how do we know it's working? As Limoncelli et. al. have said, "If you aren't monitoring it, you aren't managing it." There are several tools which...
(Part 1 one of this series gave the background and rationale, and part 2 covered the basics of how NTP works.) Getting NTP Depending on how you install Linux, you might already have a pretty workable NTP client, but for the tools we'll be working...
(Part 1 covered the background and rationale. Part 3 is about installation and configuration.) What is NTP? NTP (Network Time Protocol) is an Internet standard for time synchronisation covered by multiple RFCs. "NTP is [arguably] the longest...