Time to live is used for computer data including DNS servers. It is nothing but time on the period of time or number of iterations or transmissions in computer and computer network technology that a unit of data (e.g. a packet) can experience before it should be discarded. Usually TTL value is 86400 seconds, which is 24 hours.
Last time check by DNStable.
MX stands for "Mail eXchanger".
Autonomous System - owner of IP addresses and unit of routing policy of the Internet
Name Server (NS) Record: Describes a name server for the domain that permits DNS lookups within several zones. The host name of the primary DNS server for the zone.
The e-mail address of the person responsible for the zone. The standard for this is the "hostmaster" alias - such as "firstname.lastname@example.org" (hostmaster.example.com in a field). In a hostmaster field @ symbol always replace by dot.
Used by secondary DNS servers to check if the zone has changed. If the serial number is higher than what the secondary server has, a zone transfer will be initiated. Often serial number is performed like date: yyyymmddnn (where nn - is a index number in current day).
How often secondary DNS servers should check if changes are made to the zone.
How often secondary DNS server should retry checking if changes are made - if the first refresh fails.
How long the zone will be valid after a refresh. Secondary servers will discard the zone if no refresh could be made within this interval.
On Same Host. Indicate, how many domain DNS A record mapped to same IP address.