Intermediate level · Module 4: Router Configuration and Static Routing · Lesson 3 of 3
Inter-VLAN Routing
Allow controlled communication between VLANs.
In this lesson you will
- Configure router-on-a-stick
- Restrict traffic between VLANs
Key concepts
subinterfacesrouter-on-a-sticklayer 3 switchesaccess control lists
The lesson
Router-on-a-stick uses one physical router interface with subinterfaces, one per VLAN, over a trunk link.
Layer 3 switches route between VLANs internally and are common in larger networks.
Use access control lists (ACLs) to allow only needed traffic — for example, guests reach only the internet.
Step by step
- Configure subinterfaces.
- Set VLAN gateways.
- Test routing between VLANs.
- Add an ACL for the guest VLAN.
Practice activity
Configure inter-VLAN routing with a guest restriction.
Expected result: Routing between VLANs with guests restricted.
Check your understanding
-
What is router-on-a-stick?
Show answer
One router interface with a subinterface per VLAN over a trunk.
-
What controls which VLANs can talk?
Show answer
Access control lists.
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