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DNS Aging and Scavenging
I have read a few posts on this, but i need to be clear on some things.
In DNS forward lookup zones, zone "ABC" has duplicate IP addresses resolving to different computer names. Obviously these are stale records.
Our DHCP lease is set to 12 hours.
What should Aging and Scavenging be set to for that zone? I can increase the DHCP lease time if needed. Do i check the "Scavenge Stale recourse records" checkbox?
How long will it take before these stale records get deleted?
In DNS forward lookup zones, zone "ABC" has duplicate IP addresses resolving to different computer names. Obviously these are stale records.
Our DHCP lease is set to 12 hours.
What should Aging and Scavenging be set to for that zone? I can increase the DHCP lease time if needed. Do i check the "Scavenge Stale recourse records" checkbox?
How long will it take before these stale records get deleted?
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Per Chris-Dent's request, reposting the link from the other (duplicate) question:
http://blogs.technet.com/networking/archive/2008/03/19/don-t-be-afraid-of-dns-scavenging-just-be-patient.aspx
Good info on the scavenging process and the intervals in that blog post.
http://blogs.technet.com/networking/archive/2008/03/19/don-t-be-afraid-of-dns-scavenging-just-be-patient.aspx
Good info on the scavenging process and the intervals in that blog post.
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ASKER
It was not checked. Any difference between days? Since this has never been scanned i assume i will have to wait 7 days? Any harm if i choose 1 day?
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No, I can't see that there would be any harm in setting the period to one day. If you do so, any old records (whose no-refresh and refresh intervals have passed) should disappear 24 hours after you click OK or Apply. After that initial scavenge, you can set the period back to 7 days...or I suppose you could leave it at one if you choose.
ASKER
Does this mean 56 entires were cleared up?
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There were 54 stale records scavenged from your server, but I don't completely understand nodes vs. records, to be honest. I've had trouble finding a detailed explanation of exactly what a node is. What I've read says that a node represents a name in DNS, and each node contains all of the records associated with that name. That makes sense, I suppose, but I don't see why you'd have more nodes scavenged than records. That implies that there were nodes inside your DNS with no associated records. This isn't outside the realm of possibility, but I don't know exactly how it could come about.
Regardless of all that, scavenging completed successfully on your server.
Regardless of all that, scavenging completed successfully on your server.
Just wanted to add a note on the above.
While the Aging intervals can be reduced in the GUI to a few short hours, you should never set the Refresh Interval lower than 24 hours. Systems with static IP addresses, including your Domain Controllers and any other servers, will be dynamically registering records and performing a Refresh once every 24 hours.
Therefore, setting a Refresh Interval lower than 24 hours will result in the removal of valid records for your servers, and a lot of hassle for you.
I agree with PaciB's conclusion, increasing the DHCP lease would be preferable if you can. If you'd like an example, my settings are these:
DHCP Lease: 16 days
No-Refresh: 4 days
Refresh: 4 days
Automatic Scavenging: Once every day
The total aging time matches up to the DHCP Renewal interval (50% of lease, 8 days).
Chris