How a name becomes an IP — and where each step can fail.
DNS Basics: how a name becomes an ip
move the first decision closer to the user
Lower TTL increases query load on authoritative.
DNS is a hierarchical, cached name resolution system. A client resolver asks recursive resolvers, which walk the hierarchy until an authoritative server returns the answer; the answer is cached at every step for the TTL.
TTL chooses tradeoff: short TTL (60s) for fast failover, long TTL (1h+) for cache hit ratio and lower load.
DNS propagation isn't a network thing; it's caches and TTLs everywhere disagreeing.
Anycast is used by every major resolver and authoritative service to bring DNS within tens of ms globally.
Lower TTL before a planned IP migration.