An unauthorized zone transfer is a threat to what type of server?

An unauthorized zone transfer is a threat to what type of server?

• Exchange
• DNS
• VMWare
• Database 

EXPLANATION

The data contained in a DNS zone may be sensitive from an operational security aspect. This is because information such as server hostnames may become public knowledge, which can be used to discover information about an organization and even provide a larger attack surface. (Wikipedia)

SOURCE

https://en.wikipedia.org/wiki/DNS_zone_transfer#Exposure_of_data