Comparing NTP implementations
The Original Guy (OG), or reference implementation, of the NTP world is ntpd
. It was created way back in the 1980s and served us well for a long time. You can use it on client machines to keep their time synchronized, or you can set it up as a time server. However, it does have several shortcomings, including numerous security problems that were found during a code audit in 2017.
The chrony
implementation, which can also be used as either a client or a server, was created from scratch to fix the shortcomings of ntpd
. Unlike ntpd
, chrony
has the following features:
- It works well on computers that have unstable network connections or that get turned off for long periods.
- It works better with virtual machines.
- It can adjust itself better when the speed of the hardware clock oscillator fluctuates due to a temperature change.
- It can achieve sub-microsecond accuracy by using hardware timestamping and a hardware reference clock.