CREST CPSA Certification Exam | High-Yield Questions
and Correct Answers , Detailed Rationales,
Networking, Web Security, Penetration Testing &
Comprehensive Study Guide | Expert Guarantee Pass
and 100% Verified Answers | Latest Exam and Newest
Version!!!!
Which transport layer protocol guarantees reliable delivery by using
acknowledgments, sequencing, and error checking?
A. UDP
B. IP
C. TCP
D. ICMP
Correct Answer: C. TCP
Rationale
Transmission Control Protocol (TCP) is a connection-oriented protocol that
establishes a session before transmitting data. It ensures reliable
communication through acknowledgments, retransmissions, sequencing, and
flow control.
Why the others are incorrect:
• A. UDP is connectionless and does not guarantee delivery.
• B. IP handles addressing and routing, not reliability.
• D. ICMP is used for diagnostics and error reporting.
Question 2
,A penetration tester needs to identify the protocol that is connectionless and
designed for speed rather than reliability. Which protocol should they select?
A. TCP
B. UDP
C. SSH
D. FTP
Correct Answer: B. UDP
Rationale
User Datagram Protocol (UDP) sends data without establishing a connection or
waiting for acknowledgments.
Characteristics include:
• Faster transmission
• Lower overhead
• No guaranteed delivery
• No retransmissions
Common UDP applications include:
• DNS
• VoIP
• Video streaming
• Online gaming
Question 3
Which protocol operates on Port 21 by default?
A. SSH
B. FTP
C. SMTP
D. DNS
,Correct Answer: B. FTP
Rationale
File Transfer Protocol (FTP) uses:
• Port 21 → Control channel
• Port 20 → Data channel (Active FTP)
FTP transfers files but sends usernames, passwords, and data in plaintext.
Security professionals frequently recommend replacing FTP with SFTP or FTPS.
Question 4
A security analyst discovers users are remotely administering Linux servers
over an encrypted connection using Port 22. Which protocol is being used?
A. Telnet
B. FTP
C. SSH
D. SMTP
Correct Answer: C. SSH
Rationale
Secure Shell (SSH)
Default Port:
22
Functions:
• Secure remote login
• Secure command execution
• File transfers (SCP/SFTP)
• Encrypted administration
Unlike Telnet, SSH encrypts all communications.
, Question 5
Which protocol should be avoided because it transmits usernames and
passwords in plaintext?
A. SSH
B. HTTPS
C. Telnet
D. DNSSEC
Correct Answer: C. Telnet
Rationale
Telnet (Port 23)
Characteristics:
• Remote terminal access
• No encryption
• Credentials visible in packet captures
Modern environments replace Telnet with SSH.
Question 6
A mail server receives outgoing email messages from client computers using
which protocol?
A. POP3
B. IMAP
C. SMTP
D. FTP
Correct Answer: C. SMTP
Rationale
Simple Mail Transfer Protocol (SMTP)
Default Port:
and Correct Answers , Detailed Rationales,
Networking, Web Security, Penetration Testing &
Comprehensive Study Guide | Expert Guarantee Pass
and 100% Verified Answers | Latest Exam and Newest
Version!!!!
Which transport layer protocol guarantees reliable delivery by using
acknowledgments, sequencing, and error checking?
A. UDP
B. IP
C. TCP
D. ICMP
Correct Answer: C. TCP
Rationale
Transmission Control Protocol (TCP) is a connection-oriented protocol that
establishes a session before transmitting data. It ensures reliable
communication through acknowledgments, retransmissions, sequencing, and
flow control.
Why the others are incorrect:
• A. UDP is connectionless and does not guarantee delivery.
• B. IP handles addressing and routing, not reliability.
• D. ICMP is used for diagnostics and error reporting.
Question 2
,A penetration tester needs to identify the protocol that is connectionless and
designed for speed rather than reliability. Which protocol should they select?
A. TCP
B. UDP
C. SSH
D. FTP
Correct Answer: B. UDP
Rationale
User Datagram Protocol (UDP) sends data without establishing a connection or
waiting for acknowledgments.
Characteristics include:
• Faster transmission
• Lower overhead
• No guaranteed delivery
• No retransmissions
Common UDP applications include:
• DNS
• VoIP
• Video streaming
• Online gaming
Question 3
Which protocol operates on Port 21 by default?
A. SSH
B. FTP
C. SMTP
D. DNS
,Correct Answer: B. FTP
Rationale
File Transfer Protocol (FTP) uses:
• Port 21 → Control channel
• Port 20 → Data channel (Active FTP)
FTP transfers files but sends usernames, passwords, and data in plaintext.
Security professionals frequently recommend replacing FTP with SFTP or FTPS.
Question 4
A security analyst discovers users are remotely administering Linux servers
over an encrypted connection using Port 22. Which protocol is being used?
A. Telnet
B. FTP
C. SSH
D. SMTP
Correct Answer: C. SSH
Rationale
Secure Shell (SSH)
Default Port:
22
Functions:
• Secure remote login
• Secure command execution
• File transfers (SCP/SFTP)
• Encrypted administration
Unlike Telnet, SSH encrypts all communications.
, Question 5
Which protocol should be avoided because it transmits usernames and
passwords in plaintext?
A. SSH
B. HTTPS
C. Telnet
D. DNSSEC
Correct Answer: C. Telnet
Rationale
Telnet (Port 23)
Characteristics:
• Remote terminal access
• No encryption
• Credentials visible in packet captures
Modern environments replace Telnet with SSH.
Question 6
A mail server receives outgoing email messages from client computers using
which protocol?
A. POP3
B. IMAP
C. SMTP
D. FTP
Correct Answer: C. SMTP
Rationale
Simple Mail Transfer Protocol (SMTP)
Default Port:
