If you want to understand a simple network, this is an example of an Inter-VLAN with a DHCP server using Packet Tracer.

On my way to learning networking and obtaining a certification, I need to understand and master basic concepts. That’s why I’m looking for lab exercises and examples online to fill that knowledge gap.

Software Required :

• We only need CISCO Packet Tracer

Step by Step Configuration Process

Step 1: Add Devices to the Workspace:

• Open CPT

• Select from End Devices and drag the devices you want onto the workspace

• Add PC’s and a Server ( you can select how many pc’s you want, but next you have to configure)

• From Network devices, drag a Switch (2960) and a Router (2911)

Step 2: Connect devices physically

• Click in the cable and connect devices ( Straight through cable)

• Take in consideration interfaces

  Router (GigabitEthernet 0/0) to the Switch (FastEthernet 0/1).

  Each PC to the Switch.

  The Server to the Switch.

Step 3: Configure VLANs on the Switch

• Click on the switch to open the configuration panel and select the CLI ( Command Line Interface)

• To create VLANs we use the following steps :

    Switch>enable                                     #start switch config 
    Switch#configure terminal
    Switch(config)#
    Switch(config)#vlan 10                           #Enter VLAN you want to create
    Switch(config-vlan)#name Sales                   #Enter VLAN name 
    Switch(config-vlan)#vlan 20
    Switch(config-vlan)#name IT
    Switch(config-vlan)#vlan 30
    Switch(config-vlan)#name HR
  

  • Now we have to assign VLANs to ports

  • Assign the PC’s to the respective VLANs

        Switch(config)#interface range FastEthernet 0/2-5
        Switch(config-if)#switchport mode access
        Switch(config-if)#switchport access vlan 10
        Switch(config-if)#exit
        Switch(config)#interface range FastEthernet 0/6-10
        Switch(config-if)#switchport mode access
        Switch(config-if)#switchport access vlan 20
        Switch(config-if)#exit
        Switch(config)#interface range FastEthernet 0/11-15
        Switch(config-if)#switchport mode access
        Switch(config-if)#switchport access vlan 30
        Switch(config-if)#exit
    

Having the interfaces is time to config the Trunk port on the Router.

Configure TRUNK port for the Router

We have to configure the ports connected to the Router as Trunk ports

A trunk port on a router or switch is a network port configured to carry traffic for multiple VLANs over a single physical connection. It uses VLAN tagging, typically through the IEEE 802.1Q standard, to distinguish between the different VLANs as data travels across the network. Trunk ports are commonly used to connect switches to each other or to routers in setups where multiple VLANs need to be managed across devices, enabling efficient use of cabling and organized network segmentation.

Switch(config)#interface FastEthernet 0/1
Switch(config-if)#switchport mode trunk
Switch(config-if)#switchport trunk allowed vlan all

Step 4: Configure the Router for Inter-VLAN Routing

Click on the Router and go to configuration window and CLI to enter the configuration mode

Router>enable
Router#configure terminal
Router(config)#

Configure Sub-Interfaces for Each VLAN:

• For each VLAN,create a sub-interface with the VLAN ID and assign an IP addresses (gateway for each VLAN):

Router(config)#interface GigabitEthernet0/0.10                    #Check interface
Router(config-if)#encapsulation dot1Q 10
Router(config-if)#ip address 192.168.10.1 255.255.255.0           #Always check addresses
Router(config-if)#exit

               ** check yoou are in the other config and out of before one **

Router(config)#interface GigabitEthernet0/0.20
Router(config-if)#encapsulation dot1Q 20
Router(config-if)#ip address 192.168.20.1 255.255.255.0
Router(config-if)#exit

               "check yoou are in the other config and out of before one"
Router(config)#interface GigabitEthernet0/0.30
Router(config-if)#encapsulation dot1Q 30
Router(config-if)#ip address 192.168.30.1 255.255.255.0
Router(config-if)#exit

                                  ** Enable Interface **
Router(config)#interface GigabitEthernet0/0
Router(config-if)#no shutdown                                    # Do not forget this step

                                  ** Save the configuration **
Router(config-if)# do wr

Step 5: Configure the DHCP Server

In this section we’re gonna config the DHCP Server

1. Click in the server, go to configuration window, and config tab to assign Static IP Address to the server.

• Select FastEthernet0 on the left, and set the IP address to 192.168.10.2 and subnet mask to 255.255.255.0, also set Default Gateway as 192.168.0.1.

2. Enable the DHCP on the server.

   • Go to the Services and DHCP, enable DHCP server toggling “ON”

   • Configure DHCP Pool for each subnet in question

• Click on ADD after each pool to save the settings

Step 6: Configure DHCP Relay on the Router

We need to go back to the Router CLI and enter to the configuration mode terminal

Configure IP Helper on each VLAN sub-interface:

For VLAN 20:

Router(config)#interface GigabitEthernet0/0.20
Router(config-subif)#ip helper-address 192.168.10.2
Router(config-subif)#exit

For VLAN 30:

Router(config)#interface GigabitEthernet0/0.30
Router(config-subif)#ip helper-address 192.168.10.2
Router(config-subif)#exit

Step 7: Configure PCs to Obtain IP Addresses via DHCP

We need to configured each PC, go to DESKTOP tab, IP CONFIGURATION and select DHCP

Each PC should received an IP address from the correct subnet range based on the previous configured VLANs

Network Diagram

Verify configuration

In a PC go to CLI and type ipconfig /all to verify the assigned IP address

You also can test connectivity using ping to other PC ect…