Round Robin Network Time Protocol

A little bit of online technology I’ve been using for the last couple of months is the pool.NTP service provided at (surprisingly) NTP is used to keep your local system clocks synchronised by using some of the bigger, more accurate clocks such as atomic or radio clocks.

Traditionally you would add three or four server names/IP addresses to your NTP configuration file and the time would be pulled down and used, the downside to this included the need to ensure the remote servers were still available and the issue of being a burden as the teeming hordes of NTP clients hit the same servers again and again.

The servers get around this problem by using round-robin DNS to make both the client configuration easy and reduce the strain on the servers themselves. In the config file instead of adding different servers you add the same entry each time, in my case I add ‘’, if you try pinging this name then each couple of tries you will receive the response from a different IP address. While this may not seem very helpful from the client side (you still have to add the config entries anyway, unless you use Debian :)) from a server operators perspective it helps spread the traffic, instead of the first few listed servers getting hit by everyone the round robin helps distribute the load.

If you’ve read this far then you probably run your own ntp client or server. If you use a client then change the config to use the pooled NTP, if you run a server then please consider adding yourself to the available servers.