Which practice is recommended after a firewall policy change?

• A. Run vulnerability testing
• B. Wait days
• C. Do nothing
• D. Reboot device

Answer: (A)

After changing a firewall policy, validating the new rules is essential. Running vulnerability testing helps you verify that the updated configuration doesn’t introduce new security gaps and that the intended protections are actually in place. This testing checks that restricted services remain blocked, allowed services still function as expected, and there aren’t unintended openings created by rule ordering, NAT changes, or implicit denies. It provides immediate feedback and helps catch misconfigurations before they can be exploited or disrupt normal traffic.

Waiting days delays detection of issues and leaves potential exposures or outages unaddressed. Doing nothing ignores the change altogether, which is risky since the policy may not behave as intended. Rebooting the device is not a standard validation step for a policy change and can be disruptive; it doesn’t directly verify that the new rules enforce the desired security posture.