What protocol synchronizes the clocks of networked computers?

• A. NTP
• B. SNTP
• C. LDAP
• D. NFS

Answer: (A)

Clocks across networked devices stay in sync so logs line up and time-based security checks stay valid. The standard way to do this is with the Network Time Protocol. It works by reaching out to time sources and using a hierarchical structure of servers called strata, with upstream servers providing reference time and downstream servers discipline their local clocks toward those references. When a device asks for time, it exchanges timestamp information to estimate both the offset between its clock and the reference clock and the round-trip delay caused by the network. Based on that data, the local clock is gradually adjusted rather than jumping abruptly, keeping all systems aligned even as network conditions change. A simpler variant exists, but it sacrifices some precision and robustness. LDAP is for directory services, and NFS is for sharing files over a network, so neither is about synchronizing time.