Glitterati2006
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Reducing the No Refresh and Refresh Interval in Windows 2003 DNS
What will happen if I reduce the No Refresh and Refresh Interval in DNS? Our is currently set to 30. I would like to set it back to the default of 7 but I'm afraid of what will happen. We are getting some duplicate entries in DNS which is why I would like to adjust the interval.
You want to set your no-refresh and refresh intervals according to the length of your DHCP lease.
The No-Refresh interval is the time between when the record was created and the time it can be renewed/refreshed. Once the refresh interval expires you have the time of the Refresh interval to update your record before it becomes stale and is scavenged.
If your DHCP lease time is set to the default of 8 days the recommended no-refresh interval would be 3 days with a refresh interval of 5 days.
Also make sure you have DNS Aging turned on for both the zone and for the server (RC the Server name in DNS console and select "Set Aging/Scavenging for all Zones", then RC the Zone, Propoerties, Aging)
You can also allow DHCP to release the DNS record when the lease is deleted. RC the scope in DHCP console and select Properties, DNS Tab, Check "Disard A and PTR records when lease is deleted".
The No-Refresh interval is the time between when the record was created and the time it can be renewed/refreshed. Once the refresh interval expires you have the time of the Refresh interval to update your record before it becomes stale and is scavenged.
If your DHCP lease time is set to the default of 8 days the recommended no-refresh interval would be 3 days with a refresh interval of 5 days.
Also make sure you have DNS Aging turned on for both the zone and for the server (RC the Server name in DNS console and select "Set Aging/Scavenging for all Zones", then RC the Zone, Propoerties, Aging)
You can also allow DHCP to release the DNS record when the lease is deleted. RC the scope in DHCP console and select Properties, DNS Tab, Check "Disard A and PTR records when lease is deleted".
ASKER
Our DHCP lease is set to 8 days and DNS aging has been turned on for the zone and the server just like it should but for some reason our refresh/no refresh intervals are set to 30 days. I'm afraid if I change that to something much less (like the default of 7) it will scavenge records that it shouldn't. You're saying this is not the case?
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There is no "no refresh" interval, there is the Refresh, retry, Minimum TTL and Expire.
For refresh, this will mean that there will be more frequent check to see whether the record/zone changed increaseing DNS traffic. If this is an expiry record change, this will mean if the zone can no be accessed from the upstream server and the period configured has been exceeded, the zone is seen as expired/Invlaid and this server will respond with a no-such zone error.