Daytime

The DAYTIME service, operating on port 13, is a protocol used to provide the current date and time to clients. It is primarily used for synchronization and logging purposes. This service is simple and typically returns the date and time in a human-readable format.

What is Daytime

The DAYTIME service, defined in RFC 867, is a protocol that operates on port 13 and is used to provide the current date and time to clients. This service is one of the oldest Internet protocols and was originally designed to help synchronize time across different systems. The DAYTIME service typically returns the date and time in a human-readable format, making it easy for users and systems to interpret.

Historically, the DAYTIME service was widely used in the early days of the Internet when more sophisticated time synchronization protocols like NTP (Network Time Protocol) were not yet developed. It provided a simple and effective way to ensure that systems had the correct time, which was crucial for logging events and coordinating activities across different machines.

Today, the DAYTIME service is largely obsolete and has been replaced by more accurate and secure time synchronization protocols such as NTP. However, it is still sometimes used in legacy systems or for educational purposes to demonstrate basic client-server interactions. Despite its simplicity, the DAYTIME service serves as an important historical milestone in the development of network protocols.

Daytime runs on TCP and UDP port 13 and is official IANA port.

Security risk

If port 13 is open and the DAYTIME service is running, it could be exploited by attackers to gather information about the system's time settings. This could potentially be used in conjunction with other vulnerabilities to launch more sophisticated attacks. Additionally, the service could be used in denial-of-service attacks if it is not properly secured.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 13. Use StackChanges to monitor if the Daytime port is closed and stays closed. StackChanges will send an alert if port 13 is open again.