CCNA Foundations: Standard ACLs — Filter Traffic by Source

Today's daily lab

Build a compact two-router, three-host topology. Implement a numbered standard ACL on the destination router to permit Client-A and deny Client-B from reaching a protected server based solely on source subnet. Verify from the end hosts that permitted traffic succeeds and denied traffic fails, and practice correct ACL placement and direction.

Learning objectives

• Author a numbered standard ACL (1–99) that matches traffic by source network only
• Place a standard ACL on the interface closest to the destination in the correct direction
• Verify ACL behavior from end hosts and interpret counters
• Differentiate standard vs. extended ACL use cases and placement

Troubleshooting focus

• Verify every link's interface status and IP addressing (`show ip interface brief`) and correct any interface that is down or misaddressed.
• Confirm each device's running configuration matches the lab objective, and bring any interface, route, or service that is not in its expected state back to health.
• Trace end-to-end reachability with ping/traceroute and isolate the first hop where forwarding fails.