A Cisco Packet Tracer network lab designed to simulate a segmented business network across IT, Finance, HR and Server departments.
The project demonstrates the configuration of VLANs, 802.1Q trunking, inter-VLAN routing, DHCP, DNS, Access Control Lists (ACLs) and network troubleshooting using Cisco networking technologies.
The network was designed around a central Cisco router and core switch, with separate access switches providing connectivity for the IT, Finance and HR departments.
Four VLANs were implemented to logically separate departmental traffic and server infrastructure:
| VLAN | Department | Network | Default Gateway |
|---|---|---|---|
| 10 | IT | 192.168.10.0/24 |
192.168.10.1 |
| 20 | Finance | 192.168.20.0/24 |
192.168.20.1 |
| 30 | HR | 192.168.30.0/24 |
192.168.30.1 |
| 40 | Servers | 192.168.40.0/24 |
192.168.40.1 |
DC01 was configured with the static address 192.168.40.10 and provides centralised DHCP and DNS services to the network.
- Cisco Packet Tracer
- Cisco IOS
- VLANs
- 802.1Q trunking
- Router-on-a-stick
- Inter-VLAN routing
- IPv4 addressing and subnetting
- DHCP
- DHCP relay
- DNS
- Extended Access Control Lists (ACLs)
- Network segmentation
- Network troubleshooting
Separate VLANs were configured for the IT, Finance, HR and Server networks, providing logical separation between departments.
Router-on-a-stick was configured on R1 using 802.1Q subinterfaces to provide communication between the four VLANs.
DC01 provides DHCP services for the IT, Finance and HR networks. DHCP relay was configured on R1 to forward requests between VLANs and the central DHCP server.
DC01 provides internal DNS services, including the dc01.home.lab record mapped to 192.168.40.10.
Extended ACLs were implemented to prevent direct communication between the Finance and HR networks while maintaining access to required server resources. The IT VLAN retains unrestricted administrative connectivity.
Three network faults were intentionally introduced, diagnosed and resolved:
- Incorrect VLAN assignment
- Incorrect default gateway
- DNS resolution failure
During implementation, an additional DHCP issue caused by the Finance and HR ACLs was identified and resolved by explicitly permitting DHCP traffic.
Detailed documentation for the complete implementation is available within the docs directory.
The project included practical troubleshooting across multiple areas of the network.
IT-PC02 was intentionally assigned to the incorrect VLAN, preventing communication with its default gateway. The issue was identified through Cisco IOS verification commands and resolved by restoring the switch port to VLAN 10.
FIN-PC01 was configured with an incorrect default gateway, preventing communication outside its local subnet. Restoring the correct gateway re-established connectivity to DC01.
HR-PC02 was configured with an incorrect DNS server. IP connectivity remained operational while hostname resolution failed, allowing the issue to be isolated specifically to DNS.
During testing, the Finance and HR ACLs initially prevented clients from obtaining DHCP leases because DHCP traffic from devices without an assigned IP address was not accounted for. The ACLs were corrected to explicitly permit DHCP traffic before applying the remaining access control rules.
cisco-network-infrastructure-lab/
│
├── README.md
├── LICENSE
│
├── docs/
│ ├── 01-lab-environment.md
│ ├── 02-network-infrastructure.md
│ ├── 03-vlan-configuration.md
│ ├── 04-inter-vlan-routing.md
│ ├── 05-dhcp-configuration.md
│ ├── 06-dns-configuration.md
│ ├── 07-network-security.md
│ ├── 08-connectivity-testing.md
│ ├── 09-troubleshooting.md
│ └── 10-lessons-learned.md
│
├── packet-tracer/
│ └── Lab.pkt
│
└── screenshots/
├── 01 - Initial Network Topology.png
├── 02 - Physical Network Connections.png
├── ...
└── 17 - DNS Troubleshooting Resolution.png