CompTIA: Advanced Security Practitioner (CASP) Exam Prep

Answer: C - The ports that must be opened on the firewall to allow FTP traffic are ports 20 and 21.

Key Takeaway: File Transfer Protocol (FTP) is a standard network protocol used to exchange and manipulate files over a TCP/IP based network, such as the Internet. FTP is built on client-server architecture and utilizes separate control and data connections between the client and server applications. FTP servers listen on the TCP port number 21. When the FTP server initiates the data connection to the FTP client, it binds the source port to port 20 on the FTP server.