DNS+DHCP. What is the correct way to set time intervals to clean up obsolete records?

Question

Domain Name System

Good afternoon.
There is a DHCP and DNS server on Windows Server. What is the correct way to set time intervals to clean up obsolete records?
There is a situation when two A records (dynamic) exist for one IP address.
Current settings:
DHCP Lease - 1 day
DNS Server (Purge Period) - 7 days
Zone (Block Interval) - 4 days
Zone (Refresh Interval) - 4 days
Thanks in advance

Answer 1

In short, here's an example: You have issued a dhcp address for x days. From the point of view of DHCP, the address will live for x days, of which x/2 days it will remain unchanged, after the expiration of the first x/2 days of life (half of the lease term), the client himself begins to contact the dhcp server for a lease extension - if the client managed to apply before the end of the full term of the lease - the lease is extended.
What happens on the DNS side - dhcp issued an address, and immediately registered a record in DNS - dhcp DOES NOT worry about the life of the record in DNS, its business is to lease addresses, and telling DNS about new leases and renewal of old ones - deleting records in DNS is its own business DNS. The term of lease of the address in dhcp does not affect the lifetime of the resource record in DNS. DNS record lifetime is affected by blocking and refresh intervals. The blocking interval is the period during which the entry cannot be updated, it can only be completely deleted. The update interval is the interval during which the record is waiting to be updated (you can update the creation date, and then the blocking period will start a new countdown), i.e. that dhcp will come and say - "the patient is alive, I will renew" - this happens as soon as the "patient" turned to DHCP after the expiration of half the lease, and the record has not yet managed to get into the DNS for cleaning, even if the blocking and updating periods have expired, but it still exists - it will have its creation date updated, and the terms will be counted from the new date. If both the blocking period and the period for updating the record on the DNS have passed, then the next time the cleaning is started, the record will be deleted.
Those. it is desirable to keep the period of blocking and updating the record equal to the time of licking - i.e. in your case, 12 hours each. And let's say the cleaning period is every hour. This will increase the load on the server, but save you the headache of duplicate entries. The more often the cleaning takes place, the less chance there will be of duplication. But there will also be an increase in the load on the DNS in direct proportion (if there are not many records, it is not critical).

Answer 2

https://habr.com/post/281410/
It is not surprising if you have an IP issued for 1 day, and cleaning occurs once a week.