1) TTL stands for “Time to Live.” It is one of the settings on your DNS setup, and it refers to the amount of time a router or server will store the the IP address information in your DNS record.
2) This has an effect if you change your DNS record. IF you have a very high TTL, some servers will wait the full time before re-checking where requests should be sent. This may lengthen the amount of time domain name propagation lasts.
3) TTL is measured in seconds. The traditional value is 86400, which is 24 hours.
