The Network Time Protocol is a protocol for synchronizing time across your network, this is especially important when utilizing Directory Services. There exists a number of time servers throughout the world that can be used to keep systems synced to each other. NTP utilizes UDP port 123. Through NTP enumeration you can gather information such as lists of hosts connected to NTP server, IP addresses, system names, and OSs running on the client system in a network. All this information can be enumerated by querying NTP server.