CREST Practitioner Security Analyst (CPSA) Practice

What is the port number typically used by NTP for time synchronization?

1. 53

2. 123

3. 443

4. 80

The correct answer is: 123

The correct answer is significant because Network Time Protocol (NTP) is designed to synchronize the clocks of computers over a packet-switched, variable-latency data network. NTP operates using a specific port number, which is port 123. This choice is standardized across networks, making it essential for network configurations and firewall rules to allow traffic through this port for proper time synchronization. Using port 123 allows NTP servers to communicate effectively with clients to provide accurate time data, ensuring that systems across the network remain in sync. This is crucial for many network operations, security protocols, logging, and transaction coordination, where precise timing is vital. The other port numbers listed have distinct purposes. Port 53 is utilized for DNS (Domain Name System) services, enabling hostname resolution. Port 443 is standard for HTTPS traffic, facilitating secure web communications, while port 80 is used for regular HTTP web traffic. Each of these ports serves a different application, emphasizing the importance of using the correct port number for NTP to ensure it functions accurately and effectively in time synchronization tasks across networks.