Goldfish Networks wordmark
IntermediatePublished 2026-07-03

CCNA EIGRP: Passive Interfaces

Bundle lab

Build and verify EIGRP on a small routed topology while marking the user-facing LAN interface as passive. You will advertise the LAN into EIGRP without forming an adjacency on that segment, preventing rogue neighbors and reducing control-plane noise. Focus on deterministic EIGRP configuration, wildcard-based network inclusion, and verification using show commands.

Track
Est. time
35 minutes
Difficulty
Intermediate
Topics

Learning objectives

  • Enable EIGRP (AS 100) with classless behavior using 'no auto-summary'.
  • Advertise only the intended subnets via precise EIGRP wildcard statements.
  • Apply 'passive-interface' on the LAN so no EIGRP neighbors form on user segments.
  • Keep the router-to-router transit active so adjacency forms normally.
  • Verify with 'show ip protocols', 'show ip eigrp interfaces', 'show ip eigrp neighbors', and 'show ip route eigrp'.
  • Explain why passive interfaces harden the edge and reduce unnecessary hellos.

Troubleshooting focus

  • AS number mismatch across routers prevents EIGRP adjacency.
  • Missing or incorrect 'network' wildcard on the transit prevents neighbor formation.
  • Marking the transit as passive stops EIGRP hellos and breaks adjacency.
  • Omitting the LAN network statement stops its advertisement even if the interface is passive.
  • Shut or mis-addressed interfaces prevent control-plane formation regardless of routing config.

Topology

Subscribe to preview this lab's topology.

See plans

Related labs

More hands-on Cisco Modeling Labs practice on the same track and topics.

Study this topic

Free guides, a command cheat sheet, and graded practice for this lab's topic.

Learn EIGRP

Grade your work

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.

Create a free account to submit your lab for grading.

Create a free account
Found a problem with this lab?

Please sign in to report a problem — tying it to your attempts lets us reproduce and fix it faster.