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BeginnerPublished 2026-07-03

EIGRP Wildcard Masks: Enabling the Right Interfaces

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Build a two-router, two-LAN EIGRP domain and practice precise wildcard-masked network statements so only the intended interfaces participate. R1 has an extra LAN on Ethernet0/2 (172.16.99.0/24) that must be excluded from EIGRP. Validate with show commands and end-host pings that the correct LANs are exchanged and the excluded LAN is not advertised.

Track
Est. time
45 minutes
Difficulty
Beginner
Topics

Learning objectives

  • Enable classic EIGRP with a consistent AS (200) and classless operation (no auto-summary).
  • Use precise wildcard-masked network statements to include specific interfaces and exclude others.
  • Verify participating EIGRP interfaces and advertised networks with show ip eigrp interfaces and show ip protocols.
  • Confirm that only intended routes appear in neighbors' routing tables (show ip route eigrp) and with host pings.

Troubleshooting focus

  • If no neighbor forms on the transit, confirm both routers use the same EIGRP AS (200) and the correct wildcard covers 10.0.23.0/30.
  • If an unintended interface shows in show ip eigrp interfaces, tighten or remove an overly-broad network statement.
  • If a LAN route is missing on the neighbor, ensure the correct LAN network statement is present and that no ACLs block EIGRP (not used here).
  • If host pings fail but EIGRP looks good, check host IP/gateway and router LAN interfaces for correct addressing and link state.

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How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
  • Grading reads your saved configuration. Export the lab from CML after you have configured it, and make sure anything you set is in the running-config — a change that only exists in a terminal session never reaches the grader.
  • You can submit as many times as you like. Your best score stands, and each attempt tells you which checks passed so you can work the gaps.
  • Scored something you believe is correct? Use Report an issue on this page — that is exactly how the grading fixes in the changelog got found.

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