When in a Zone window you have the option to Hide/Show the TTL column for that window. To hide or show the TTL columns, select the appropriate choice in the Zone menu. TTL is the Time to Live for that record, the maximum period the record recommends that other servers cache it. If you’d like to enter individual TTL records, show the TTL column, and enter the data. Otherwise it is usually more convenient to hide the TTL column.

All records may be commented, you may hide or show the comments field. Data in a comments field does not affect record functionality