Build a Multi-Site Corporate Network

Design a 3-site network with DHCP relay, DNS, and web services.

Introduction

30 Second Summary

When you connect to a network at work, your laptop automatically gets an address, finds websites by name, and loads internal company pages. Behind the scenes, multiple network services coordinate across routers and switches to make that seamless experience possible.

In this project, you will build a multi-site corporate network in Cisco Packet Tracer that connects a headquarters with two branch offices. You will configure DHCP for automatic IP addressing, DNS for domain name resolution, and static routing for site-to-site connectivity.

What You'll Build

A 3-site enterprise network with centralized DHCP, DNS, and web services hosted at headquarters, accessible from all branch offices via statically routed WAN links.

By the end of this project, you'll have:

A 3-router, 3-switch topology with proper IP addressing across 5 subnets (3 LANs and 2 WAN links) connected by static routes.
A centralized DHCP server distributing IP addresses to PCs at all sites using relay agents.
A DNS server and web server enabling all PCs to browse an internal company website by domain name.
Secret Mission: Extend the network with a 4th branch office and scale routing, DHCP, and DNS to reach it.

Are there any prerequisites?

No prior networking experience is required. This guide walks you through installing Cisco Packet Tracer (free) and covers all CLI basics as you go.

Before We Start

To build your multi-site corporate network, you need a tool that lets you simulate routers, switches, and servers without buying physical hardware.

Cisco Packet Tracer is a free network simulator built by Cisco for exactly this purpose. In this step, you'll install it on your Linux machine and get comfortable with its interface.

In this step, get ready to:

Install Cisco Packet Tracer on your Linux machine.
Verify the workspace loads and you can place network devices.
Practice using the router CLI.

Install Cisco Packet Tracer

Packet Tracer requires a free Cisco Skills for All account for both downloading the installer and logging in to the application.

Open your browser and go to https://skillsforall.com.
Click Sign Up and create a free account.
Once logged in, navigate to the Resource Hub at https://skillsforall.com/resources/lab-downloads.
Download the Packet Tracer 8.2.2 installer for Ubuntu 64-bit (the .deb file).

Check whether you already have Packet Tracer installed by running this in your terminal:

which packettracer

✔️ I see a file path and my version is 8.2.2 or later

If which returned a path (like /usr/local/bin/packettracer), Packet Tracer is already on your machine.

Launch Packet Tracer by running packettracer in your terminal.
Click Help in the top menu bar, then click About.
Confirm the version shows 8.2.2 or later.

If you see 8.2.2 or later, close Packet Tracer and continue to the next substep. If you see an older version, close it and follow the instructions in the third tab to upgrade.

ⓧ I see a path but my version is older than 8.2.2

You have Packet Tracer installed, but an older version. Installing the new .deb file replaces the old version automatically.

Close Packet Tracer if it is currently running.
Open your terminal and navigate to the folder where you downloaded the .deb file (usually ~/Downloads).
Install the new version by running:

sudo apt-get install ./CiscoPacketTracer_822_Ubuntu_64bit.deb

During installation, a License Agreement prompt appears. Use the Tab key to navigate to Accept and press Enter.
Once complete, launch Packet Tracer by running:

packettracer

Install command failed?

Make sure you are in the same directory as the .deb file. Run ls and confirm you see CiscoPacketTracer_822_Ubuntu_64bit.deb in the output.
If you see a dependency error, run sudo apt-get -f install to fix missing dependencies, then retry the install command.
Help me troubleshoot this Packet Tracer installation issue

ⓧ No output or command not found

Packet Tracer is not installed yet. Follow these steps to install it from scratch.

Open your terminal and navigate to the folder where you downloaded the .deb file (usually ~/Downloads).
Install Packet Tracer by running:

sudo apt-get install ./CiscoPacketTracer_822_Ubuntu_64bit.deb

What does this command do?

The apt-get install command installs the .deb package file and automatically resolves any missing dependencies that Packet Tracer needs to run.

During installation, a License Agreement prompt appears. Use the Tab key to navigate to Accept and press Enter.
Once complete, launch Packet Tracer by running:

packettracer

Install command failed?

Make sure you are in the same directory as the .deb file. Run ls and confirm you see CiscoPacketTracer_822_Ubuntu_64bit.deb in the output.
If you see a dependency error, run sudo apt-get -f install to fix missing dependencies, then retry the install command.
Confirm you are running Ubuntu 20.04 or 22.04 (64-bit). Packet Tracer 8.2.2 requires one of these versions.
Help me troubleshoot this Packet Tracer installation issue

Verify your installation works

With Packet Tracer open, you should see a blank workspace with a device panel along the bottom of the screen.

Look at the bottom device panel. Confirm you can see the categories: Routers, Switches, End Devices, and Connections.
Click Routers in the bottom panel, then select a 2911 router from the device list.
Click anywhere on the workspace to place the router.
Click End Devices in the bottom panel, then select a PC.
Click the workspace to place the PC.
Select both devices by clicking and dragging a box around them.
Press the Delete key to remove them from the workspace.

Your workspace should now be empty again. This confirms you can place and remove devices successfully.

Don't see the device categories?

The device panel is at the very bottom of the Packet Tracer window. If your window is too small, try maximizing it.
If the panel appears but shows no devices, make sure you are logged in. Check the top-right corner for your account name.
Help me find the device categories in Packet Tracer

Practice the router CLI

Every router and switch in Packet Tracer has a CLI tab that simulates the real Cisco command-line interface. You'll use this constantly throughout the project to configure interfaces and routes.

Click Routers in the bottom panel, then navigate to Generic in the subcategory row.
Select Router-PT and place it on the workspace.
Double-click the router to open its configuration window.
Click the CLI tab.

You should see a Router> prompt. Practice entering the three main CLI modes by running these commands one at a time:

enable

What does this do?

The enable command moves you from User EXEC mode (Router>) into Privileged EXEC mode (Router#). This gives you access to all show and debug commands.

Your prompt should now show Router#. Enter global configuration mode by running:

configure terminal

What does this do?

The configure terminal command enters Global Configuration mode (Router(config)#). This is where you make changes to the router's settings like interfaces, routing, and hostnames.

Your prompt should now show Router(config)#. Exit back to Privileged EXEC mode by running:

end

What does this do?

The end command exits from any configuration mode straight back to Privileged EXEC mode (Router#). You'll use this after finishing configuration tasks.

Your prompt should be back to Router#.
Close the router configuration window by clicking the X in its top-right corner.
Click the router on the workspace to select it, then press Delete to remove it.

Your workspace is empty again. You now know the three CLI modes you'll use throughout this project.

CLI tab showing a blank screen?

Click inside the black CLI area and press Enter. Sometimes the CLI needs a keypress to activate.
If you still see nothing, close the router window, delete the router, place a new Router-PT, and try again.
Help me get the CLI working in Packet Tracer

Your environment is ready. Next up, you'll start building the network topology by placing routers, switches, and cables to connect your three corporate sites.

Build the Network Topology and Address the WAN Links

Your environment is set up and you have confirmed that Cisco Packet Tracer launches successfully. Now it is time to build the physical network and give each router interface an IP address.

A corporate network with multiple branch offices needs routers to connect each site, switches to connect local devices, and a carefully planned addressing scheme so traffic can flow between locations. In this step, you will place all the devices, cable them together, and assign IP addresses to every router interface.

In this step, get ready to:

Place 3 routers and 3 switches, then cable them together with the correct cable types.
Configure IP addresses on the WAN links between routers.
Configure IP addresses on the LAN interfaces connecting each router to its switch.

Place the routers, switches, and cables

Every network starts with the physical topology. You need 3 routers (one per site) and 3 switches (one per site) connected with the right cable types.

In the bottom device panel, click Routers (the router icon in the device category bar).
Select Generic from the subcategory, then drag a Router-PT onto the left side of the workspace.
Drag two more Router-PT devices onto the workspace, placing them in a horizontal line to the right of the first one.
Label them by clicking on each router's default text and renaming to: HQ-Router (left), Branch1-Router (center), Branch2-Router (right).
Click Switches in the device category bar, select Generic, and drag a Switch-PT below each router (3 switches total).
Click Connections in the device category bar (the lightning bolt icon).
Select Copper Straight-Through cable.
Click HQ-Router, choose FastEthernet0/0, then click the switch below it and choose FastEthernet0/1.
Repeat for Branch1-Router (FastEthernet0/0 to its switch FastEthernet0/1) and Branch2-Router (FastEthernet0/0 to its switch FastEthernet0/1).
Now select Copper Cross-Over cable from the Connections panel.
Click HQ-Router, choose FastEthernet0/1, then click Branch1-Router and choose FastEthernet0/1. This is WAN link 1.
Click Branch1-Router, choose FastEthernet1/0, then click Branch2-Router and choose FastEthernet0/1. This is WAN link 2.

Why two different cable types?

Copper Straight-Through cables connect devices of different types (router to switch, PC to switch). Copper Cross-Over cables connect devices of the same type (router to router).

In real enterprise networks, these connections would use fiber or dedicated WAN circuits. Packet Tracer uses cross-over Ethernet cables to simulate point-to-point WAN links between routers.

You should now see link indicator lights on all cables. Orange dots mean the interfaces are not yet configured. They will turn green once you enable them in the next substeps.

Don't see a port option when connecting?

Make sure you selected the correct cable type before clicking the device. If a port is greyed out, it is already in use. Check that you are clicking on the correct router.

help me figure out why I cannot connect my routers in Packet Tracer

Configure the WAN link IP addresses

Each router interface needs an IP address so devices know where to send traffic. WAN links use /30 subnets, which provide exactly 2 usable addresses per link.

What is the IP addressing scheme?

Your network uses 5 subnets across 3 sites:

HQ LAN: 192.168.10.0/24
Branch1 LAN: 192.168.20.0/24
Branch2 LAN: 192.168.30.0/24
WAN1 (HQ to Branch1): 10.0.0.0/30
WAN2 (Branch1 to Branch2): 10.0.0.4/30

The /30 mask (255.255.255.252) on WAN links is standard practice for point-to-point connections because it wastes no addresses.

Click on HQ-Router and go to the CLI tab.
Configure the WAN interface by entering these commands:

enable
configure terminal
hostname HQ-Router
interface FastEthernet0/1
ip address 10.0.0.1 255.255.255.252
no shutdown
exit

What do these commands do?

enable enters privileged exec mode, giving you access to configuration commands.
configure terminal enters global configuration mode where you can change the router's settings.
hostname HQ-Router sets the router's name so you can identify it in the CLI prompt.
interface FastEthernet0/1 selects the WAN-facing port for configuration.
ip address 10.0.0.1 255.255.255.252 assigns the first usable IP from the 10.0.0.0/30 subnet.
no shutdown enables the interface. Cisco interfaces are off by default.

Close the HQ-Router window. Click on Branch1-Router and go to the CLI tab.
Configure both WAN interfaces by entering these commands:

enable
configure terminal
hostname Branch1-Router
interface FastEthernet0/1
ip address 10.0.0.2 255.255.255.252
no shutdown
exit
interface FastEthernet1/0
ip address 10.0.0.5 255.255.255.252
no shutdown
exit

Why does Branch1-Router have two WAN interfaces?

Branch1-Router sits in the middle of the chain. It connects to HQ-Router on one side (FastEthernet0/1) and to Branch2-Router on the other (FastEthernet1/0).

Each WAN link is a separate /30 subnet, so each interface gets its own address from its respective subnet.

Close the Branch1-Router window. Click on Branch2-Router and go to the CLI tab.
Configure the WAN interface by entering these commands:

enable
configure terminal
hostname Branch2-Router
interface FastEthernet0/1
ip address 10.0.0.6 255.255.255.252
no shutdown
exit

Verify the WAN links are up by typing end to return to privileged exec mode, then running this command:

end
show ip interface brief

You should see FastEthernet0/1 listed with IP 10.0.0.6 and a status of up. The WAN cable indicators should now show green on the connected router ports.

Interface still showing as down?

If the status column shows "administratively down", you missed the no shutdown command. Re-enter the interface and run it.

If it shows "down" (not administratively), the cable is not connected to that port. Delete the cable and reconnect using the correct port names.

help me troubleshoot why my router interface is showing as down in Packet Tracer

Configure the LAN interfaces on each router

Each router also needs an IP address on its LAN-facing interface. This address becomes the default gateway for all devices on that local network.

Click on HQ-Router and go to the CLI tab. Enter these commands to configure the LAN interface:

enable
configure terminal
interface FastEthernet0/0
ip address 192.168.10.1 255.255.255.0
no shutdown
exit

Click on Branch1-Router and go to the CLI tab. Enter these commands:

enable
configure terminal
interface FastEthernet0/0
ip address 192.168.20.1 255.255.255.0
no shutdown
exit

Click on Branch2-Router and go to the CLI tab. Enter these commands:

enable
configure terminal
interface FastEthernet0/0
ip address 192.168.30.1 255.255.255.0
no shutdown
exit

What do the LAN addresses mean?

Each router's FastEthernet0/0 connects to the local switch. The .1 address (e.g. 192.168.10.1) is the gateway that local PCs will use to reach other networks.

The /24 mask (255.255.255.0) gives each LAN 254 usable host addresses, which is plenty for an office.

Verify all interfaces on any router by running show ip interface brief from privileged exec mode.

All interfaces should show a status of up and protocol up. Every cable indicator on the workspace should now be green.

Some links still showing orange?

Orange indicators on switch-to-router links are normal for a few seconds while Spanning Tree Protocol converges. Wait 30 seconds and they should turn green.

If a link stays orange, click the router and run show ip interface brief to confirm FastEthernet0/0 shows "up / up". If it shows "administratively down", enter the interface and run no shutdown.

help me troubleshoot why my router-to-switch links are still orange in Packet Tracer

✔️ Awesome, I've got everything!

Great. Double check you have green indicators on all cables and that each router has a hostname set.

ⓧ I'd like to double check the full configuration

Run show ip interface brief on each router. Here is what you should see:

HQ-Router:

Interface          IP-Address      OK? Method Status    Protocol
FastEthernet0/0    192.168.10.1    YES manual up        up
FastEthernet0/1    10.0.0.1        YES manual up        up

Branch1-Router:

Interface          IP-Address      OK? Method Status    Protocol
FastEthernet0/0    192.168.20.1    YES manual up        up
FastEthernet0/1    10.0.0.2        YES manual up        up
FastEthernet1/0    10.0.0.5        YES manual up        up

Branch2-Router:

Interface          IP-Address      OK? Method Status    Protocol
FastEthernet0/0    192.168.30.1    YES manual up        up
FastEthernet0/1    10.0.0.6        YES manual up        up

Your physical topology is built and every interface has an IP address. Next up, you will configure static routes so that traffic can actually flow between the three sites.

Configure Static Routing for Full Connectivity

Your routers have IP addresses on every interface, but they only know about the networks directly attached to them. HQ-Router has no idea that 192.168.20.0/24 or 192.168.30.0/24 exist at the branch offices.

In this step, you will add static routes to each router so every subnet can reach every other subnet. Once routing is complete, traffic can flow end-to-end across all five subnets in your network.

In this step, get ready to:

Add static routes on HQ-Router to reach both branch LANs and the second WAN link.
Add static routes on Branch1-Router to reach HQ and Branch2 LANs.
Add static routes on Branch2-Router to reach HQ LAN, Branch1 LAN, and the first WAN link.

Add static routes to HQ-Router

HQ-Router is directly connected to the 10.0.0.0/30 WAN link and the 192.168.10.0/24 LAN. It has no knowledge of the Branch1 LAN, Branch2 LAN, or the second WAN link between Branch1 and Branch2. You need to tell it where to send packets destined for those networks.

Click HQ-Router in your workspace and go to the CLI tab.
Enter the following commands to add three static routes:

enable
configure terminal
ip route 192.168.20.0 255.255.255.0 10.0.0.2
ip route 192.168.30.0 255.255.255.0 10.0.0.2
ip route 10.0.0.4 255.255.255.252 10.0.0.2
end

What do these routes do?

Each ip route command tells the router: "To reach this destination network, forward packets to this next-hop IP address."

The first route sends traffic for the Branch1 LAN (192.168.20.0/24) to 10.0.0.2, which is Branch1-Router's WAN interface.
The second route sends traffic for the Branch2 LAN (192.168.30.0/24) to the same next hop. Branch1-Router will forward it onward to Branch2.
The third route handles the WAN2 link (10.0.0.4/30) between Branch1 and Branch2, so HQ can reach those interfaces too.

Verify the routes were added by running this command:

show ip route

You should see three lines starting with S (for static) pointing to 192.168.20.0, 192.168.30.0, and 10.0.0.4 in the routing table.

Don't see lines starting with S?

Make sure you typed end after the route commands to exit configuration mode. You must be in privileged exec mode (the HQ-Router# prompt) to run show ip route.
Double check you used the correct subnet masks. LAN routes use 255.255.255.0 and the WAN route uses 255.255.255.252.
Confirm the next-hop address 10.0.0.2 is reachable. Run ping 10.0.0.2 from HQ-Router. If it fails, the WAN interface on Branch1-Router may not be up.

Why aren't my static routes showing up on HQ-Router?

Add static routes to Branch1-Router

Branch1-Router sits in the middle of the chain. It is directly connected to both WAN links, so it already knows about 10.0.0.0/30 and 10.0.0.4/30. It only needs routes to the two LANs it is not directly connected to.

Click Branch1-Router and go to the CLI tab.
Enter the following commands to add two static routes:

enable
configure terminal
ip route 192.168.10.0 255.255.255.0 10.0.0.1
ip route 192.168.30.0 255.255.255.0 10.0.0.6
end

Why does Branch1-Router use two different next hops?

Branch1-Router has a router on each side. To reach the HQ LAN, it forwards packets left toward 10.0.0.1 (HQ-Router). To reach the Branch2 LAN, it forwards packets right toward 10.0.0.6 (Branch2-Router).

This is the key difference from HQ-Router, which sends everything through a single next hop. Branch1-Router must choose the correct direction for each destination.

Verify by running:

show ip route

You should see two static routes marked with S pointing to 192.168.10.0 and 192.168.30.0.

Routes missing or showing wrong next hop?

Verify the next-hop IPs carefully. The route to HQ uses 10.0.0.1 (the other end of WAN1) and the route to Branch2 uses 10.0.0.6 (the other end of WAN2).
If you accidentally typed the wrong next hop, re-enter the correct ip route command from configuration mode. Then remove the incorrect route with no ip route followed by the wrong command's parameters.

Help me fix my static routes on Branch1-Router.

Add static routes to Branch2-Router

Branch2-Router is at the far end of the chain. All traffic heading toward HQ or Branch1 must go through Branch1-Router, so every route on Branch2-Router points to the same next hop.

Click Branch2-Router and go to the CLI tab.
Enter the following commands to add three static routes:

enable
configure terminal
ip route 192.168.10.0 255.255.255.0 10.0.0.5
ip route 192.168.20.0 255.255.255.0 10.0.0.5
ip route 10.0.0.0 255.255.255.252 10.0.0.5
end

Why does every route use the same next hop?

Branch2-Router only has one path out of its network. Whether traffic is heading to HQ LAN, Branch1 LAN, or the first WAN link, the only way to get there is through 10.0.0.5 (Branch1-Router's WAN2 interface).

This is the same pattern you saw on HQ-Router. Routers at the edges of a chain always funnel traffic through their single neighbor.

Verify the routes are present by running:

show ip route

You should see three static routes marked with S in the output.

Now test end-to-end connectivity. From Branch2-Router, ping HQ-Router's LAN interface to prove traffic can cross all three routers:

ping 192.168.10.1

You should see replies coming back successfully. This confirms that packets travel from Branch2-Router through Branch1-Router to reach HQ-Router's LAN interface and back again.

Ping fails or times out?

Go back to each router and run show ip route. Every router must have routes to ALL subnets it is not directly connected to. A missing route on any router in the path will cause the ping to fail.
The first ping attempt sometimes shows a timeout on the first packet because of ARP resolution. Try the ping a second time before troubleshooting.
Verify that all interfaces are still up. Run show ip interface brief on each router and confirm every interface shows up in both the Status and Protocol columns.

My ping from Branch2-Router to 192.168.10.1 is failing. Help me troubleshoot.

✔️ Awesome, I've got everything!

Great. Make sure you see successful ping replies from Branch2-Router to 192.168.10.1 before moving on.

ⓧ I'd like to double check the full configuration

Here are all the static routes that should be on each router. Compare these against your show ip route output on each device.

HQ-Router static routes:

ip route 192.168.20.0 255.255.255.0 10.0.0.2
ip route 192.168.30.0 255.255.255.0 10.0.0.2
ip route 10.0.0.4 255.255.255.252 10.0.0.2

Branch1-Router static routes:

ip route 192.168.10.0 255.255.255.0 10.0.0.1
ip route 192.168.30.0 255.255.255.0 10.0.0.6

Branch2-Router static routes:

ip route 192.168.10.0 255.255.255.0 10.0.0.5
ip route 192.168.20.0 255.255.255.0 10.0.0.5
ip route 10.0.0.0 255.255.255.252 10.0.0.5

Your network now has full routing connectivity across all five subnets. Next up, you will set up a centralized DHCP server at HQ and configure relay so PCs at every site can automatically receive IP addresses.

Set Up DHCP Server with Relay Across All Sites

Your routers now know how to reach every subnet in the network thanks to static routing. The next challenge is giving each device an IP address without manually configuring them one by one.

In this step, you'll set up a centralized DHCP server at headquarters that automatically hands out IP addresses to devices at all three sites. To make this work across different subnets, you'll configure DHCP relay on the branch routers.

In this step, get ready to:

Place and configure a DHCP server at HQ with address pools for all 3 LANs.
Configure DHCP relay on branch routers to forward requests to HQ.
Place PCs at each site and verify they receive IP addresses automatically.

Place and configure the DHCP server at HQ

Every device on the network needs an IP address, a default gateway, and a DNS server address. Instead of typing these into each PC manually, a DHCP server automatically distributes this information to any device that asks.

From the bottom device panel, click End Devices (the icon with a monitor and phone).
Drag a Server-PT onto the workspace near HQ-Switch.
Label it DHCP-Server by clicking the text label below the device.
Connect DHCP-Server to HQ-Switch using a Copper Straight-Through cable (click Connections in the bottom panel, then select the solid black line).
Click the DHCP-Server's FastEthernet0 port, then click any available port on HQ-Switch.

Now assign the server a static IP address so other devices can always find it at the same address.

Click DHCP-Server to open its configuration window.
Go to the Desktop tab.
Click IP Configuration.
Select Static and enter the following values:
IP Address: 192.168.10.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.10.1

Why a static IP for the server?

DHCP servers must have a fixed address because every device on the network needs to know where to send its IP address request. If the server's own address changed, nothing could find it.

Next, configure the DHCP service with three pools, one for each site's subnet.

In the DHCP-Server configuration window, click the Services tab.
Click DHCP in the left sidebar.
Make sure the Service toggle at the top is set to ON.

You'll see a default pool called serverPool already listed. You'll modify this into your first pool for the HQ LAN.

In the Pool Name field, change it to HQ-Pool.
Set Default Gateway to 192.168.10.1.
Set DNS Server to 192.168.10.3.
Set Start IP Address to 192.168.10.100.
Set Subnet Mask to 255.255.255.0.
Click Save.

Now add a second pool for the Branch1 LAN.

In the Pool Name field, type Branch1-Pool.
Set Default Gateway to 192.168.20.1.
Set DNS Server to 192.168.10.3.
Set Start IP Address to 192.168.20.100.
Set Subnet Mask to 255.255.255.0.
Click Add.

Add the third pool for the Branch2 LAN.

In the Pool Name field, type Branch2-Pool.
Set Default Gateway to 192.168.30.1.
Set DNS Server to 192.168.10.3.
Set Start IP Address to 192.168.30.100.
Set Subnet Mask to 255.255.255.0.
Click Add.

What do these 3 pools do?

Each pool tells the DHCP server which range of IP addresses to hand out, along with the correct gateway and DNS server for that specific subnet.

The DHCP server matches incoming requests to the right pool based on the subnet the request came from. This way, a PC at Branch1 gets a 192.168.20.x address with the correct gateway, not an HQ address.

You should see all three pools listed in the table at the bottom of the DHCP service panel.

Don't see all 3 pools?

Make sure you clicked Save for the first pool (HQ-Pool) and Add for the Branch1-Pool and Branch2-Pool. If a pool is missing, re-enter its values and click Add again.

help me fix my DHCP pool configuration in Packet Tracer

Configure DHCP relay on the branch routers

The DHCP server sits on the HQ subnet (192.168.10.0/24). PCs at Branch1 and Branch2 are on different subnets, and DHCP requests are broadcast messages that don't cross routers by default.

What is DHCP relay?

When a PC first boots, it shouts "I need an IP address!" as a broadcast. Routers normally block broadcasts from leaving the local subnet.

The ip helper-address command tells the router to intercept DHCP broadcasts and forward them as unicast packets to the DHCP server's IP address. This is called DHCP relay.

Configure DHCP relay on Branch1-Router by entering these commands in its CLI tab:

enable
configure terminal
interface FastEthernet0/0
ip helper-address 192.168.10.2
end

What does this command do?

The ip helper-address 192.168.10.2 command is placed on FastEthernet0/0 because that's the interface facing the Branch1 LAN. Any DHCP broadcast arriving on this interface gets forwarded to the DHCP server at 192.168.10.2.

Configure DHCP relay on Branch2-Router by entering these commands in its CLI tab:

enable
configure terminal
interface FastEthernet0/0
ip helper-address 192.168.10.2
end

Both branch routers will now relay DHCP requests from their local PCs to the centralized DHCP server at HQ.

Worried you typed it on the wrong interface?

The ip helper-address must go on the LAN-facing interface (FastEthernet0/0 on both branch routers). If you accidentally placed it on a WAN interface, enter that interface's config and run no ip helper-address 192.168.10.2 to remove it, then apply it to FastEthernet0/0 instead.

help me verify my ip helper-address is on the correct interface

Place PCs and verify DHCP assignment

Now place PCs at each site and confirm they automatically receive the correct IP configuration from the DHCP server.

From End Devices in the bottom panel, drag 2 PC-PT devices near HQ-Switch.
Connect each PC to HQ-Switch using a Copper Straight-Through cable.
Drag 2 PC-PT devices near Branch1-Switch and connect them with Copper Straight-Through cables.
Drag 2 PC-PT devices near Branch2-Switch and connect them with Copper Straight-Through cables.

You should now have 6 PCs total across your network. Configure each one to use DHCP.

Click a PC at HQ to open its configuration window.
Go to Desktop > IP Configuration.
Select DHCP.
Wait a few seconds for the IP address fields to populate automatically.
Repeat for all 6 PCs.

What should I see?

After selecting DHCP, each PC should automatically receive an IP address, subnet mask, default gateway, and DNS server. The values depend on which site the PC is at:

HQ PCs: addresses starting at 192.168.10.100, gateway 192.168.10.1.
Branch1 PCs: addresses starting at 192.168.20.100, gateway 192.168.20.1.
Branch2 PCs: addresses starting at 192.168.30.100, gateway 192.168.30.1.

Verify the assigned addresses by clicking a PC, going to Desktop > Command Prompt, and running:

ipconfig

You should see the correct IP address, subnet mask, and default gateway for that PC's site.

Branch PCs showing 0.0.0.0 or not getting an address?

This usually means the DHCP relay isn't working. Check these common causes:

Verify ip helper-address 192.168.10.2 is on FastEthernet0/0 of the branch router (not a WAN interface).
Confirm the DHCP server's static IP is 192.168.10.2 and its default gateway is 192.168.10.1.
Make sure the static routes from the previous step are still in place. The DHCP server needs a route back to the branch subnets for its replies to arrive.
Try toggling the PC's IP Configuration between Static and DHCP to trigger a fresh request.

help me troubleshoot why my branch PCs aren't getting DHCP addresses

Your centralized DHCP server is now distributing IP addresses to all three sites automatically. Next up, you'll add DNS and a web server so every PC can browse an internal company website by name.

Configure DNS and Web Server for Internal Domain Resolution

Your network is fully connected and every PC automatically gets its IP address from the centralized DHCP server. But right now, if someone at Branch2 wants to access a resource at HQ, they would need to know the exact IP address.

In a real corporate network, employees type domain names like www.corp.com instead of memorizing IP addresses. In this step, you will set up a DNS server to translate names into IPs, and a web server to host the company homepage.

In this step, get ready to:

Set up a DNS server with an A record for the internal company domain.
Configure a web server hosting a custom company homepage.
Verify that PCs at all 3 sites can browse the company website by domain name.

Place the DNS-Web-Server and configure DNS

A DNS server translates human-readable domain names into IP addresses. You will place a new server at HQ that handles both DNS and web hosting on the same device.

From the bottom device panel, go to End Devices > End Devices.
Drag a Server-PT onto the workspace near your HQ network (next to the DHCP-Server).
Click the label below the new server and rename it to DNS-Web-Server.
Connect DNS-Web-Server to HQ-Switch using a Copper Straight-Through cable.

Now give the server a static IP address so other devices can always find it.

Click the DNS-Web-Server to open its configuration window.
Go to the Desktop tab, then click IP Configuration.
Select Static and enter the following values:
IP Address: 192.168.10.3.
Subnet Mask: 255.255.255.0.
Default Gateway: 192.168.10.1.

Why 192.168.10.3?

Your DHCP server already uses 192.168.10.2, so the DNS-Web-Server takes the next available address. This is also the DNS server IP you configured in the DHCP pools earlier, so all PCs already know to query this address for name resolution.

Now configure the DNS service with an A record that maps your company domain name to this server's IP.

In the DNS-Web-Server configuration window, click the Services tab.
Select DNS from the left-hand service list.
Make sure the DNS service is turned ON.
In the Name field, enter www.corp.com.
Set the Type to A Record.
In the Address field, enter 192.168.10.3.
Click Add.

You should see the new A record appear in the DNS records list below.

What is an A record?

An A record (Address record) is the most fundamental type of DNS entry. It maps a domain name directly to an IPv4 address.

When a PC asks "what is the IP for www.corp.com?", the DNS server looks up its A records and responds with 192.168.10.3. The PC then connects directly to that IP.

Don't see the DNS service option?

Make sure you clicked on the DNS-Web-Server device (not the DHCP-Server). Also confirm you are on the Services tab, not the Desktop or Config tab.

Help me troubleshoot my DNS service setup in Packet Tracer.

Configure the web server on the same device

The DNS server now knows that www.corp.com points to 192.168.10.3. You need something actually running at that address to serve a web page. The Server-PT device in Packet Tracer can run multiple services at once, so you will enable HTTP on the same device.

Still in the DNS-Web-Server's Services tab, select HTTP from the left-hand service list.
Confirm the HTTP service is turned ON (it should be on by default).
In the file list, click on index.html to open it in the editor.
Select all the existing default text and replace it with:

<html>
<head><title>Corp HQ</title></head>
<body>
<h1>Welcome to Corp HQ - Internal Company Portal</h1>
<p>You have successfully reached the corporate web server.</p>
</body>
</html>

Click Save to store the new homepage.

What does the web server do?

When a PC's web browser connects to 192.168.10.3 on port 80 (the default HTTP port), the server responds with the contents of index.html. This is the same basic process that serves every website on the internet.

Test DNS and web access from every site

The real test of your entire network is whether a PC at a remote branch can type a domain name and see a web page from HQ. This single action exercises every service you have configured: DHCP, DNS, static routing, and HTTP.

Click on one of your Branch2 PCs (Branch2-PC1 or Branch2-PC2) to open its configuration window.
Go to the Desktop tab, then click Web Browser.
In the URL bar, type www.corp.com and click Go.

You should see your custom homepage displaying "Welcome to Corp HQ - Internal Company Portal".

What just happened behind the scenes?

A lot happened in that single page load. The PC at Branch2 already received its IP address and DNS server address from DHCP (via relay through Branch2-Router to the DHCP server at HQ).

When you typed www.corp.com, the PC sent a DNS query to 192.168.10.3. That query traveled through Branch2-Router, across the WAN links via static routes, and reached the DNS server at HQ. The DNS server replied with the IP address. The PC then connected to the web server at that same IP and loaded the page.

Now verify the other sites can browse the same page.

Open the Web Browser on a PC at HQ (HQ-PC1 or HQ-PC2). Type www.corp.com and click Go.
Open the Web Browser on a PC at Branch1 (Branch1-PC1 or Branch1-PC2). Type www.corp.com and click Go.

Both should display the same custom company homepage.

Finally, verify DNS resolution directly using the command prompt.

On any PC, go to Desktop > Command Prompt.
Run the following command to verify DNS resolution:

nslookup www.corp.com

You should see the DNS server respond with the address 192.168.10.3. This confirms DNS resolution is working correctly.

Page won't load or DNS times out?

Run ipconfig on the PC and check that the DNS Server shows 192.168.10.3. If it shows a different address or is blank, re-release and renew the DHCP lease by toggling the PC's IP Configuration from DHCP to Static and back to DHCP.

Also verify that the DNS-Web-Server has the correct gateway (192.168.10.1) and that the cable connecting it to HQ-Switch shows green link lights on both ends.

Help me troubleshoot why my PCs cannot browse www.corp.com in Packet Tracer.

Secret mission

Add a 4th Branch Office

Your 3-site network is running smoothly. But what happens when the company opens a new branch? In this secret mission, you'll add a 4th site to the network, extend routing tables across all routers, and prove the new office gets full DHCP, DNS, and web access from day one.

Clean Up Your Resources

This project runs entirely inside Cisco Packet Tracer's local simulator. There are no cloud resources, no paid services, and no ongoing costs.

Decide whether to keep your simulation file for future reference or remove it from your machine.

Resources you used:

Cisco Packet Tracer application (installed locally).
Your saved Packet Tracer simulation file (.pkt).

Keep everything running

No action needed. Choose this if you plan to keep experimenting with your network topology or want to revisit the lab later.

Save your workspace by clicking File then Save As in Packet Tracer.
Choose a location you can find later (like your Desktop) and name the file something memorable like corporate-network.pkt.
Cisco Packet Tracer stays installed on your machine and is free to use for future labs.

Pause - I'll come back to this later

Save your work and close Packet Tracer to free up system memory. Your file stays on disk for when you return.

Save your workspace by clicking File then Save in Packet Tracer.
Close Cisco Packet Tracer.

Delete - I don't want to use this again

Remove all project files and optionally uninstall Cisco Packet Tracer from your system.

Close Cisco Packet Tracer if it is still open.
Delete your .pkt simulation file by running this command (replace the path with where you saved your file):

rm ~/Desktop/corporate-network.pkt

To uninstall Cisco Packet Tracer from your system, run:

sudo apt-get remove packettracer
sudo apt-get autoremove

What does this do?

The first command removes the packettracer package from your system. The second command cleans up any leftover dependencies that were only needed by Packet Tracer.

Nice Work!

You just built a multi-site corporate network from scratch. Three offices, five subnets, centralized services, and end-to-end connectivity across it all.

You've learned how to:

Design and configure a multi-subnet IP addressing scheme using /24 subnets for LANs and /30 subnets for point-to-point WAN links, then implement static routing so every device can reach every other device across all sites.
Set up a centralized DHCP server with ip helper-address relay on branch routers, distributing IP addresses automatically to clients across three remote subnets.
Configure a DNS server with an A record and an HTTP web server, then verify full service delivery by browsing an internal company website by domain name from remote branch PCs.
Secret Mission: Extended the network with a 4th branch office, proving you can scale the architecture by adding new subnets, updating routing tables, and extending DHCP and DNS services.

Ready to quiz yourself?