 An older common TTL value for DNS was 86400 seconds, which is 24 hours.A TTL value of 86400 would mean that, if a DNS record was changed on the authoritative nameserver, DNS servers around the world could still be showing the old value from their cache for up to 24 hours after the change.Newer DNS methods that are part of a disaster recovery (DR) system may have some records deliberately set extremely low on TTL.