Whoever controls a zone can hand over any branch that hangs from it. Delegating means writing two records in your zone (an NS and its glue) and no longer answering for anything below.
Shows how the DNS name space is split into zones through delegation, using the chain IANA, Red.es, UAH and departments. In "Step by step" the tree is coloured by zone and the zone files (SOA, NS, A) change with each delegation, with an optional pause to predict. In "Your turn" the student acts as each zone owner, creates domains and hosts, hands over branches by giving a server name and address, and sees when the glue record is mandatory. Clicking a name shows the chain of referrals leading to its authoritative server. It distinguishes a domain from a zone.
Concepts: zone delegation, zone, NS record, glue record, authoritative server, zone file, referral, domain versus zone.
Network Architecture I, Session 2.1 · Enrique de la Hoz, University of Alcalá · License CC BY-SA 4.0 · Source and catalogue on GitHub · DOI 10.5281/zenodo.23285664