Internet UDP port 123 is primarily used by the Network Time Protocol (NTP), a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. This protocol is used to synchronize all participating computers to within a few milliseconds of Coordinated Universal Time (UTC). Examples of software that use this protocol include NTPd and Chrony, which are commonly used in Unix-like operating systems for time synchronization.
UDP port 123 is primarily used for Network Time Protocol (NTP) services. In the past, hackers have exploited this port for conducting Distributed Denial of Service (DDoS) attacks. They use a method called NTP amplification, where a small forged request is sent to the NTP server, causing it to send a large response to the victim's IP address. This overwhelms the victim's network with unwanted traffic, leading to a denial of service. This type of attack is particularly effective due to the amplification factor, where a small request can generate a significantly larger response.
