Final answer:
The statement is true; firewalls limit access by port or protocol to protect internal networks from unauthorized access and potential security threats.
Step-by-step explanation:
The statement is true: firewalls are traditionally configured to limit access by port or protocol, from some or all external systems. A firewall acts as a barrier between your internal network and external networks, such as the internet. It is designed to prevent unauthorized access to or from the internal network by filtering incoming and outgoing traffic based on a predetermined set of security rules.
By restricting access through specific ports and protocols, the firewall can block certain types of traffic, effectively protecting the network from a wide range of security threats, including hackers, malware, and other malicious activities.
An external force is defined as a force generated outside the system of interest that acts on an object inside the system. Therefore, it is correct to say that an external force acts on an object inside the system.