I plan to move the external ns zone outside the country, 3 entries at the domain registrar will indicate external addresses(outside the country) and 1 entries will indicate my local ns(inside the country). When querying the registrar, he gives out the results randomly, that is 4 records are swapped.
Questions:
Let's say one NS server will always be in the disabled state, in this case, if a request to domain registrer returns a response, where the disabled NS is the first in the list, what will be the result of the client?.
I assume that the next NS will be requested, and so on in turn. If it true, can you please tell me the RFC number where this behavior is documented (I don’t know how to correctly make a request in google).
Wikipedia has quite a useful list with all RFC's https://en.wikipedia.org/wiki/Domain_Name_System#RFC_documents
As an intro into the original intended behavior of the DNS spec this is probably the section you're after: https://datatracker.ietf.org/doc/html/rfc1034#section-5.3.3
As for what will be the result for queries sent to a disabled name server:
I would expect a difference in behaviour when the name server is powered off (resulting in a connection time-out) , compared to the server being powered on, running a DNS server but not responding for your domain i.e the server returns a valid DNS response with a DNS error code such as
REFUSED,SERVFAILorNXDOMAIN.The latter error will be returned to the client, but the first scenario should result in the query being asked by the resolver to (one of) the other authoritative name servers for your domain.As Patrick commented : what will then actually happen (in edge cases and failure scenarios) depends on the specific software and version.