While time servers keep networked devices synchronized, they don’t recognize daylight saving shifts. As several experts noted in our recent "Daylight saving changes: No Y2K, but there could be headaches" story, a time server will do nothing to solve daylight-saving snafus.

To help clear up the issue, Network World Senior Editor Jennifer Mears spoke with Paul Skoog, a product marketing manager at Symmetricom, which sells time and frequency products and services, including network time servers. Here’s an edited transcript of their conversation:

What are network time servers, what do they do and what is their role in the network?

Time servers are clocks that reside on the network, either on the Internet or inside your firewall, that provide time to servers, workstations, routers, etc. on the LAN. The time provided by a time server is always UTC [Coordinated Universal Time], is usually traceable back to a national time source such as NIST [National Institute of Standards and Technology}or USNO [the U.S. Naval Observatory], and supports the Network Time Protocol (NTP). UTC has no time zone and is related to atomic time and the earth’s spin rate. Probably the most popular source of precise UTC time is via the GPS satellite system. With a GPS-referenced network time server on your network, you have a clock that’s accurate down to the sub-microsecond level, as well as being reliable and secure.

To actually synchronize the time on your network, you need to configure servers and workstations to get their time from the time server by way of an NTP daemon in the operating system or an NTP time client. This will synchronize the client machine typically to a few milliseconds to UTC internally. Most people don’t realize this. It’s the user of the operating system that configures the local time zone for that machine. The beauty of UTC and time servers is that they can all be synchronized very closely to one another, independent of time zones, because time zones happen locally on your computer.

Can you update your time server so that it is in compliance with the daylight-saving change for your local network?

No, NTP time servers are time-zone agnostic. They serve only UTC time. Say you put a time client on your computer and configure it to get time from a time server. It can be any time server on the planet, could be one that I sell you, could be one that the government provides out on the Internet. Your time client will synchronize to that time server and it will always be to UTC time. Locally, your operating system, such as a Microsoft OS, keeps track of time according to UTC. But it makes an adjustment when it displays the time or for time stamps, because you told your computer that you are located in a certain time zone. What the operating system now does is get UTC time from the time server and then adjusts it according to your time zone and daylight saving rules. But internally, hidden from you, you’re synchronizing to the time server using UTC time.