CompTIA Updated N10-009 Exam Questions and Answers by dolcie

•Since this issue occurred after a configuration change on a Layer 3 switch, the most likely cause is misconfigured ACLs (Access Control Lists).

•ACLs control which traffic is allowed or denied, so an incorrect ACL may be blocking access to the file server.

•Why not the other options?

•Switching loop (B): A switching loop occurs at Layer 2 (not Layer 3) and causes network-wide broadcast storms, not just loss of access to a file server.

•Duplicate IP addresses (C): This would cause connectivity issues for the devices with the conflict, but not necessarily prevent all users from accessing the file server.

•Wrong default route (D): The default route is used for traffic leaving the local network. If users are unable to access an internal file server, this is unlikely to be the issue.

Comprehensive and Detailed Explanation (paraphrased, aligned to N10-009):

In a spine–leaf architecture, endpoints (including servers, firewalls, and WAN/edge routers) connect to leaf switches. Leaf switches then uplink to spine switches; spine switches do not have endpoints connected directly to them. Therefore, a WAN router (an external/edge device) should connect to the leaf layer—often specifically to a “border leaf” that handles external connectivity.

Why not B. Core or D. Spine? In spine–leaf, “core” isn’t a formal layer, and spines are designed only to interconnect leafs, not to terminate endpoints.

Why not A. Access? “Access” is a term from the traditional three-tier model (access–distribution–core). In modern spine–leaf language, the analogous layer for endpoint attachment is the leaf.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — Data center and campus architectures (spine–leaf vs. three-tier), roles of leaf/spine, WAN/edge connectivity points.

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