This read-only 32-bit integer reports the time-to-live, in seconds, of a dynamic DNS host mapping entry, indicating how long the entry remains valid before it must be refreshed. Admins use it to judge how current a cached name-to-address mapping is and when it's due to expire and be re-resolved. For example, a TTL of 3600 means the device will treat that domain-to-IP mapping as valid for up to one hour before requiring a fresh lookup.