Which protocol allows all devices to synchronize to a central time service?

The protocol that facilitates synchronization of all devices to a central time service is Network Time Protocol (NTP). NTP is designed specifically to synchronize the clocks of computers over packet-switched data networks. It operates using a hierarchical system of time sources referred to as strata, with higher strata providing more accurate time than lower ones.

NTP ensures that all devices in a network can achieve consistent and accurate time, which is critical for various applications, including logging events, orchestrating distributed systems, and maintaining security protocols that rely on precise timestamps. By using NTP, systems can communicate effectively, maintain logs that are synchronized, and perform operations that are time-sensitive without discrepancies that might arise due to clock drift.

The other protocols listed serve different purposes. DNS (Domain Name System) is used for resolving domain names to IP addresses, FTP (File Transfer Protocol) focuses on transferring files between a client and a server, and HTTP (Hypertext Transfer Protocol) is used for transferring hypertext requests and information on the web. None of these protocols are intended for synchronizing time among devices.