NS (NameServer) records identify the authoritative nameservers that hold the DNS zone for a domain. They're what the registry stores at the parent level, and what you control via your registrar's nameserver settings.
For modusdom.com, the NS records at the .com registry might say:
modusdom.com. NS ns1.modusdom.com.
modusdom.com. NS ns2.modusdom.com.When anyone wants to look up modusdom.com, their resolver asks the .com registry "who hosts DNS for this?" Verisign's servers reply with the NS records, and the resolver then asks the listed nameservers for the actual A, MX, TXT, etc. records.
NS records inside your zone vs. at the registry: there are technically two copies — one stored at the registry (the "parent zone" copy) and one inside your own DNS zone (the "in-bailiwick" copy). Both should match. The registry copy is what actually controls delegation; the in-zone copy exists for caching and consistency.
To switch nameservers (e.g., move from Modusdom DNS to Cloudflare), you change the NS records via your registrar's control panel — not by editing a zone file. The registrar updates the registry, propagation begins, and within a few hours queries route to the new nameservers.
