Which service is essential for providing time synchronization across servers in a mixed environment?

The essential service for providing time synchronization across servers in a mixed environment is Network Time Protocol (NTP). NTP is designed specifically for synchronizing the clocks of computers over a network, ensuring that all devices maintain the same time accuracy. This is crucial in environments where timestamps of logs, file updates, transactions, and scheduled tasks need to be consistent across different servers and systems.

Accurate time synchronization helps prevent issues related to time discrepancies, such as improper logging of events or failure in scheduled tasks. In mixed environments where different operating systems may be in play, NTP facilitates uniformity by allowing all systems to synchronize their clocks with a reliable time source, which is often provided by dedicated NTP servers or even GPS devices.

While Domain Name System (DNS) is important for resolving domain names to IP addresses, and Dynamic Host Configuration Protocol (DHCP) is responsible for automating the assignment of IP addresses to devices, neither of these protocols deals with timekeeping. File Transfer Protocol (FTP) is used for transferring files over the network and is also unrelated to time synchronization. Therefore, NTP stands out as the critical service specifically aimed at providing accurate time synchronization across various servers in a mixed environment.