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Free CCNA | VLANs (Part 3) | Day 18 | CCNA 200-301 Complete Course

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Published on Nov 25, 2025 This response is partially generated with the help of AI. It may contain inaccuracies.

Table of Contents

Introduction

This tutorial provides a comprehensive guide on inter-VLAN routing using Layer 3 switches, based on the content from the CCNA 200-301 course. Understanding VLANs and their configuration is essential for network management and optimization. This guide will walk you through the steps necessary to configure a native VLAN on a router, analyze network traffic with Wireshark, and set up inter-VLAN routing through Switch Virtual Interfaces (SVIs).

Step 1: Configure Native VLAN on a Router

To set up a native VLAN on a router, follow these steps:

Access the Router Configuration
- Connect to the router using a console cable.
- Enter privileged EXEC mode by typing enable.
- Access global configuration mode with configure terminal.
Identify the Interface
- Determine which interface you will configure as the native VLAN (e.g., GigabitEthernet0/1).
Set the Native VLAN
- Enter the interface configuration mode:
```
interface GigabitEthernet0/1
```
- Assign the native VLAN:
```
switchport access vlan [VLAN_ID]
```
- Replace [VLAN_ID] with the appropriate VLAN number.
Save Configuration
- Exit the interface configuration mode:
```
exit
```
- Save the running configuration to startup configuration:
```
write memory
```

Step 2: Analyze Traffic with Wireshark

Wireshark is a powerful tool for analyzing network packets. Here's how to use it to analyze traffic between switches and routers:

Capture Traffic
- Start Wireshark and choose the appropriate network interface to capture traffic.
- Apply a filter to focus on VLAN traffic, for example:
```
vlan
```
Examine Traffic from SW2 to R1
- Start the capture while generating traffic between SW2 and R1.
- Look for packets related to the native VLAN.
Examine Traffic from R1 to SW2
- Perform similar analysis for traffic going from R1 back to SW2.
- Check for any anomalies or issues in the packet flow.

Step 3: Configure Inter-VLAN Routing via SVI

Setting up inter-VLAN routing involves configuring Switch Virtual Interfaces (SVIs). Follow these steps:

Enable IP Routing
- Access the switch configuration mode:
```
configure terminal
```
- Enable IP routing:
```
ip routing
```
Configure SVIs for Each VLAN
- For each VLAN, create an SVI:
```
interface vlan [VLAN_ID]
ip address [IP_ADDRESS] [SUBNET_MASK]
no shutdown
```
- Replace [VLAN_ID], [IP_ADDRESS], and [SUBNET_MASK] with the respective values for each VLAN.
Verify SVI Status
- Ensure the SVIs are in an 'up/up' state. To check the status, use:
```
show ip interface brief
```
Test Routing Between VLANs
- Use ping commands from devices in different VLANs to verify that inter-VLAN routing is functional.

Conclusion

In this tutorial, you learned how to configure a native VLAN on a router, analyze traffic using Wireshark, and set up inter-VLAN routing with Switch Virtual Interfaces. Understanding these concepts is vital for effective network management. Next steps include practicing these configurations in a lab environment or using simulation software like Cisco Packet Tracer to reinforce your learning.

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