I am currently migrating a DNS zone from one DNS server provider to another. I am trying to estimate how long it will take for the change to propagate, and to understand what the delay might be if I chose to rollback mid-stream.
Previously, I thought I could do:
dig example.com ns
To see what the remaining TTL on the NS record was, but now I understand that this NS record is the NS record for subdomains in the zone, and not the NS record that emanates from the root servers, which is the one that ultimately determines to which name server the query will be sent.
I tested this by setting up a test record in the zone in each of the providers:
Provider1 test.example.com 10.0.0.1 Provider2 test.example.com 192.168.0.1
For both providers, the TTL on the NS records in 0, while the NS records at the TLD Registrar level point to the name servers of Provider1.
When I change the NS records in the zone at Provider1, I can see this reflected in NS queries almost immediately (using 'dig example.com ns').
However, when I send a query for an A record, ie
it always returns
regardless of what the NS records in the zone at Provider 1 are set to.
On this basis, I've concluded that the NS records within the zone file are irrelevant to the migration, and that only the name servers records at the TLD level are important.
However, I can't get a read on how long it is likely for a change there to propagate, either forward or back.
Is it possible to query what TTL are am working with for records emanating from the TLD root servers?