TTL

TTL (Time To Live) is a numeric value, measured in seconds, that tells DNS resolvers and caches how long they can reuse a record before requesting a fresh copy from the authoritative nameserver.

When a resolver first queries a nameserver for an A record, CNAME, MX record, or any other DNS record, it receives both the answer and its TTL. The resolver caches that answer and serves it to subsequent queries without contacting the authoritative server again—until the TTL countdown reaches zero, at which point the cache entry expires.

Different caches (ISP resolvers, operating systems, browsers) each store the same record independently and decrement its TTL from the moment they cached it, so the effective time a record remains cached varies by location.

Example TTL values:

• 3600 (1 hour) — standard for stable records like A records
• 300 (5 minutes) — used before planned changes to allow quick propagation
• 86400 (24 hours) — common for less-frequently-changed records

You set TTL when you create or edit a DNS record in your provider's control panel. Lower TTLs increase DNS query traffic but enable faster DNS propagation when you make changes; higher TTLs reduce queries but mean changes take longer to roll out globally.

Use InfraNest's DNS lookup tool to see the TTL of any live record.

TipDrop the TTL to around 300 seconds a day before a planned change, then raise it again afterwards to reduce resolver load.