What does TTL (Time To Live) mean for DNS records?

TTL controls DNS caching duration:

Measured in seconds. TTL of 3600 = cache for 1 hour.

How it works:

Resolver queries authoritative server

Receives record with TTL value

Caches result for TTL seconds

After TTL expires, queries again

Lower TTL (300-600):

Changes propagate faster

More DNS queries (higher load)

Good during planned changes

Higher TTL (3600-86400):

Better caching, fewer queries

Changes propagate slower

Good for stable records

Balance between update speed and query efficiency.

Expiration date on cached information. Short expiry means frequent checks for updates.