ISA/IEC 62443 Cybersecurity Fundamentals Specialist — Question 20

Why is OPC Classic considered firewall unfriendly?

Answer options

• A. OPC Classic uses DCOM, which dynamically assigns any port between 1024 and 65535.
• B. OPC Classic is allowed to use only port 80.
• C. OPC Classic works with control devices from different manufacturers.
• D. OPC Classic is an obsolete communication standard.

Correct answer: A

Explanation

The correct answer is A because OPC Classic employs DCOM, which can open a wide range of ports, complicating firewall configurations. Options B, C, and D are incorrect as they do not accurately represent the technical limitations and characteristics of OPC Classic regarding firewall compatibility.