Which port is used by Network Time Protocol?

Which port is used by Network Time Protocol?

• A. Network Time Protocol (NTP)
• B. Telnet Protocol
• C. Simple Mail Transfer Protocol (SMTP)
• D. Trivial File Transfer Protocol (TFTP)

Answer: (A)

Time synchronization in networks is handled by a protocol that uses UDP for fast, lightweight message exchange. The port used by Network Time Protocol is 123. NTP runs over UDP so clocks can be updated with small, frequent messages without the overhead of establishing a connection, and it relies on a hierarchy of time sources to gradually adjust the local clock. The standard port is 123, defined by IANA for NTP. Other common protocols use different ports: Telnet uses TCP port 23, SMTP uses TCP port 25, and TFTP uses UDP port 69. Those are not used for time synchronization.

Time synchronization in networks is handled by a protocol that uses UDP for fast, lightweight message exchange. The port used by Network Time Protocol is 123. NTP runs over UDP so clocks can be updated with small, frequent messages without the overhead of establishing a connection, and it relies on a hierarchy of time sources to gradually adjust the local clock. The standard port is 123, defined by IANA for NTP. Other common protocols use different ports: Telnet uses TCP port 23, SMTP uses TCP port 25, and TFTP uses UDP port 69. Those are not used for time synchronization.