I have domain.com, and it's currently served by ns1/ns2.oldisp.com. I need to change the authoritative nameservers to ns1/ns2.newisp.com.
Please tell me if my understanding of this is correct:
Every domain has NS records which are authoritative for the domain in question.
domain.com. IN NS ns1.oldisp.com.
Every domain also has an authoritative nameserver that can be set via the registrar. My registrar says: "Changes to your name servers are sent to the registry immediately. However, it takes 24-48 hours for the changes to fully take effect."
When a client asks for my domain, it will ask the root servers for the authoritative domain server for .com. That will give them a.gtld-servers.net (for example), and then it will ask that server for the authoritative server for domain.com, e.g. ns1.oldisp.com. That's provided, and away we go....
I want the switch to happen quickly, so how do I tell the authoritative server for .com (e.g. a.gtld-servers.net ) to lower the TTL on my domain.com record, so clients don't cache which nameservers are authoritative (and thus keep ns1.oldisp.com around for 24-48 hours)? Is that even possible?