The document discusses secure MAC address learning methods for port security, identifying the 'restrict method' as not being secure. It states that 'sticky', 'dynamic', and 'static' methods are secure. Therefore, option b (restrict method) is the correct answer as it lacks security.

1. Which is not a secure MAC address learning for port security?
A. Sticky method
B. Restrict method
C. Dynamic method
D. Static method
Solution
B is correct. Restrict is not a secure MAC address learning method.
A, C, and D are incorrect. They are all secure MAC address learning methods for port security.