Port 37TIME Protocol

The TIME protocol is a simple network service used to synchronize computer clocks by providing the current time in a standardized format. Designed primarily for legacy systems, it transmits the number of seconds elapsed since midnight on January 1, 1900. While functional, TIME is largely superseded by more sophisticated protocols like NTP and is seldom used in modern networks..

transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
2/10

safe

lookups
6,293

rank 802 of 993 · top 81%

Technical Details

what runs on :37

The TIME protocol, defined in RFC 868, is a basic network service intended to provide a machine-readable timestamp. When a client connects, the server responds with a 32-bit unsigned integer representing the number of seconds that have elapsed since 00:00 (midnight) on January 1, 1900, GMT. This facilitates simple synchronization of the client's clock with that of the server.

It operates over both TCP and UDP on port 37. For TCP, the client initiates a connection and reads the 4-byte time response from the server before closing the connection. With UDP, the client sends a datagram, and the server responds with the timestamp in a 4-byte UDP packet.

Due to its minimal implementation, TIME lacks features such as error correction, latency compensation, or authentication. Consequently, modern systems favor Network Time Protocol (NTP), which provides greater accuracy and resilience.

Security Information

exposure of :37

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

network services averages 3.9 across 604 ports — this one sits 1.9 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common Vulnerabilities:

  • Susceptible to spoofing attacks since there is no authentication.
  • Vulnerable to man-in-the-middle (MITM) attacks altering timestamps.
  • Because it can be used as an amplifier in UDP-based DDoS attacks, exposure may be exploited by attackers.
  • Potential information leakage revealing network clock settings, which can aid attackers in timing further attacks.

Common Mitigations:

  • Disable the TIME protocol service unless explicitly required, favoring more secure alternatives like NTP with authentication.
  • Implement access controls and limit which hosts can query the service.
  • Employ firewall rules to block port 37 from untrusted networks.
  • Use network monitoring to detect abnormal traffic patterns aimed at port 37.
  • Maintain up-to-date network security infrastructure to reduce exposure.

the 8 most looked-up other ports in network services — 604 ports carry that label.

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted