VLAN Configuration

Intermediate Networking
Cisco IOSip linkvconfigtcpdump

Objective

Hands-on practice with vlan configuration in a network lab environment.

Tools & Technologies

  • Cisco IOS
  • ip link
  • vconfig
  • tcpdump

Key Commands

vlan 10
switchport access vlan 10
ip link add link eth0 name eth0.10 type vlan id 10
ip addr add 10.10.0.1/24 dev eth0.10

Lab Steps

01
Create VLANs

Create VLANs on a managed switch and assign access ports.

02
Trunk Ports

Configure trunk ports to carry multiple VLANs between switches.

03
Linux VLAN Interface

Create 802.1Q VLAN subinterfaces on Linux for inter-VLAN testing.

04
Verify Isolation

Verify traffic isolation between VLANs using ping and tcpdump.

Challenges Encountered

  • Native VLAN mismatch causes trunk issues
  • Forgetting to add VLANs to trunk ports blocks traffic

Key Takeaways

  • VLANs provide Layer 2 segmentation without physical separation
  • Always document VLAN IDs and their purposes