What DNS is and how authoritative nameservers work

DNS — the Domain Name System — is the internet's address book. It translates human names like example.com into the IP addresses machines actually connect to.

When someone visits your site, their resolver (usually run by their ISP) works up the chain: it asks the root, which points to the TLD registry (e.g. .com), which points to your domain's authoritative nameservers — Transcom's three servers. Those servers hold the master copy of your zone (all your records) and give the definitive answer.

Two ideas matter throughout:

• Authoritative vs caching — our nameservers are authoritative: they hold the truth. Resolvers cache answers for a while to be fast.
• TTL (time to live) — each record carries a TTL saying how long resolvers may cache it. A short TTL means changes are seen quickly; a long TTL means fewer lookups but slower updates.

Understanding this explains why a DNS change is instant on our side but can take a little while to be visible everywhere.