Network Time Protocol (NTP) provides a time server that all clients on a network can query to keep their system clocks in sync. It is critical to keep each computer on a network referencing the same time, for several reasons.
Several subsystems rely on having correct time, such as Kerberos, which uses synchronized time to prevent [...]

Another way to keep a primary or secondary DNS server secure is to restrict zone transfers to authorized sources only. By default, the “Allows zone transfer” checkbox is enabled for each zone created, which means that anyone who can issue queries against a server can also request a copy of the entire zone file. This [...]