Networking Fundamentals · lesson 12 of 17 · 15 min

Firewalls and ACLs

summary: Firewalls and access control lists decide which traffic is allowed or denied. Start with the required service, source, destination, and port, then use the narrowest rule that supports the need.

question: Which firewall rule follows least privilege?

options:

• Allow all inbound traffic
• Allow only the required service from approved sources
• Disable logging
• Allow every port temporarily

correct: Allow only the required service from approved sources

explanation: Narrow, documented rules reduce exposure while preserving the required service.

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