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Question
Monday, March 19, 2018 8:18 PM
I have read a number of posts concerning best practices around DHCP Lease timing with DNS Scavenging.
I understand it is best practice to set the Scavenging Period (TimeStamp+No Refresh+Refresh) w/ the variable of the Scavenging Period set at the DNS server level to be LESS/SHORTER than the Lease Period on DHCP.
I know setting Scavenging Periods higher than Lease Periods when I have DHCP set to the clients update their own DNS is an issue.
My question is; are there ANY negatives to setting the DNS Scavenging period shorter than the Lease at all?
Example: Let's say my DHCP Lease was 45 Days and I set No Refresh at 7 Days, Refresh at 7 Days and Scavenge at 7 Days.
My DNS records would Scavenge every 14-21 Days while my DHCP Leases could last 45 Days. Meanwhile I have DHCP set to the clients update their own DNS as opposed to setting DHCP update DNS for clients. Anyone see any issues with this?
All replies (6)
Monday, March 19, 2018 8:46 PM âś…Answered
Hi
As far as i know there is no problem having the DNS scavenging shorther than DCHP lease.
In my environment we had huge stale records and we did all the clean up and we followed the thump rule it is running for the past 5 Yrs. i didn't find any problem so far.
Thanks
Syed.
Dont forget to mark as Answered if you found this post helpful.
Monday, March 19, 2018 8:21 PM
Hi,
Please refer this article which help you in understanding more on your requirments.
Thanks
Syed.
Dont forget to mark as Answered if you found this post helpful.
Monday, March 19, 2018 8:24 PM
I have read both before posting. They are both great at explaining why we set the DNS Scavenging period shorter than the Lease Period but don't state if there are any gotchas.
Monday, March 19, 2018 8:26 PM
Also, I find many people saying to set the lease and scavenging period as close as possible. If scavenging period needs to be before the Lease expires; why do people say as close as possible?
Monday, March 19, 2018 8:32 PM
Hi,
The thumb rule for scavenging of DNS is always less than DHCP lease scope. In your case 21 days is lesser than 42 which will work perfectly.
Thanks
Syed.
Dont forget to mark as Answered if you found this post helpful.
Monday, March 19, 2018 8:37 PM
Thanks Syed! But I am trying to determine, that while it IS best practice, are there any known problems with having the DNS Scavenging SHORTER than the DHCP Lease?