Networking - MCQ Practice Questions

Which of the following statements about the OSI model is correct?

An organization implements end-to-end encryption for all data transfers. At which OSI layer is this encryption most commonly implemented?

What is the primary difference between a hub and a switch in terms of OSI layers?

A firewall configured to block all traffic on port 443 is operating at which OSI layer?

A network administrator observes that devices on different subnets cannot communicate despite being connected to the same router. The devices have valid IP addresses and can ping the router. At which OSI layer should the administrator focus troubleshooting, and what is the most likely issue?