Every DNS answer includes a TTL (Time To Live). This tells recipients how long to cache the answer.
Caching happens at multiple levels:
- Your browser caches DNS lookups
- Your OS maintains a DNS cache
- Your home router may cache
- Your ISP's resolver definitely caches
High TTLs ( seconds = day) reduce DNS traffic but slow down changes. Low TTLs ( seconds = minutes) allow faster changes but increase query load.