CREST Practitioner Security Analyst (CPSA) Practice

The protocol that is associated with port 500 (UDP) is ISAKMP, which stands for Internet Security Association and Key Management Protocol. ISAKMP is primarily used for establishing security associations and cryptographic keys in the context of Internet Protocol Security (IPsec). It is a foundational component of VPN (Virtual Private Network) technologies, allowing for secure communications over potentially insecure networks. ISAKMP operates over UDP on port 500 to facilitate the exchange of security information for the negotiation of security associations. This allows devices to agree on how to protect data being transmitted between them, ensuring confidentiality, integrity, and authenticity. Other protocols listed in the options, such as HTTP, FTP, and SMTP, serve different functions. HTTP (Hypertext Transfer Protocol) is used for web traffic and operates over port 80 (TCP). FTP (File Transfer Protocol) is used for file transfers and typically operates over ports 21 (control) and 20 (data, TCP). SMTP (Simple Mail Transfer Protocol) is utilized for sending emails and usually operates over port 25 (TCP). This context highlights why ISAKMP is the correct association for port 500 (UDP).