Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a Server with a statically set IP address of

It has a Dynamic DNS entry matching its computer name to its IP

Every hour on the hour it changes its DNS entry to a random IP address in my subnet.

What in the world is going on here? The IP is statically set on the NIC. DNS just feels like changing its entry ever hour.

When I checked the timestamp I also noticed that just about all my DNS entries are updated every hour.

enter image description here

My DHCP lease time is set to 6 hours for both the 10.200 zone and 10.54 zone.

The 10.200 zone has all IP addresses excluded from the range. Reservations only.

Any help would be greatly appreciated. Thanks!

share|improve this question
I have added additional information to my question. – Ruisu Oct 14 '11 at 20:46
up vote 1 down vote accepted

DNS A records register\refresh updates are stamped ROUNDED DOWN to the nearest hour - you're seeing normal behaviour

share|improve this answer

According to your other question you have a DHCP server running. So someone has set the lease time to one hour.

share|improve this answer
Do you really think every client would recieve the lease at exactly the same time? See the 'on the hour' point, and that all of clients are exactly at the same time to the second. It seems extremely unlikely to me that this is 'normal' renewals for a 1 hour lease. – Zoredache Oct 14 '11 at 19:23
@Zoredache No, not really. But who told you that the timestamp column is the date where the lease was given out? – mailq Oct 14 '11 at 19:25
Since your answer is about the lease time, I am assuming standard Windows Dynamic DNS behavior on the client & DHCP server. It tries to update, when a DHCP request has been received. It seems very unlikely that every client machine would in sync. – Zoredache Oct 14 '11 at 19:42
So it is not every machine updating on the hour. Approx 20 or so. Then, another group of 20 the next hour and so on. It just DNS entry that is having the issue of changing the IP address for no reason. – Ruisu Oct 14 '11 at 20:43

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.