How resolution actually works.
WHAT THE HIERARCHY IS
Root servers, knowing where each top-level domain is served Top-level domain servers, knowing where each domain is served Authoritative servers, holding the actual records
WHAT A RESOLVER DOES
Performs the full sequence on behalf of a client, and caches the result.
WHAT A STUB RESOLVER IS
The minimal client on a device, which asks a recursive resolver.
WHAT RECURSIVE MEANS
Following the chain to completion, rather than returning a referral.
WHAT AUTHORITATIVE MEANS
Holding the actual data for a zone, rather than a cached copy.
WHY THAT DISTINCTION MATTERS
A resolver problem and an authoritative problem look similar and require different action.
WHAT A ZONE IS
A portion of the namespace administered as a unit.
WHAT DELEGATION IS
A parent zone pointing to the servers authoritative for a child.
WHAT GLUE RECORDS ARE
Address records for nameservers within the zone they serve, held by the parent.
WHY THEY ARE NECESSARY
Without them, resolving the nameserver's name would require querying the nameserver itself.
WHAT TO CHECK WHEN RESOLUTION FAILS
Whether the delegation is correct at the parent, and whether glue is present and accurate.
