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Understand the two TTL settings of SOA record

SOA TTL

Minimum (default) TTL controls the resource records in DNS zone.

How about set up the TTL as follows:

SOA TTL2

 

TTL

iMac1-PC and PC1 have Windows 7 OS installed. I use only IPv4 address by unbounding IPV6 from "Local Area Connection" adapter. and

Netsh interface 6to4 set state disabled

netsh interface isatap set state disabled

netsh interface teredo set state disabled

So, iMac1-PC host will have only one address (191.121.12.5) automatically registered in dongle.com zone and PC1 has 191.121.12.6 address automatically registered.

From PC1,

IPCONFIG /flushdns

IPCONFIG /displaydns

PING iMac1-PC

Right away, run IPCONFIG /displaydns

The Time To Live value is always below 1200. The Minimum (default) TTL value has no effect. Why?

How about to manually create a record TestMe with 191.121.12.5? You will find the Minimum (default) TTL applies to it.

To find out why, I convert the Active Directory Integrated zone to a standard primary zone type. Open the dongle.com.dns file.

TTL3

I don't have a clue what services will use the TTL value of SOA itself.

When a secondary zone or stub zone cannot communicate with its primary zone for the time defined in EXPIRE BOX, the secondary zone should discard its data.