Cisco Packet Tracer

  • This project was aimed at simulating a small office network consisting of four VLANs in Cisco Packet Tracer to gain a better understanding of networking concepts, specifically the following:

    • DHCP Configuration

    • Inter-VLAN Routing

    • Network Address Translation (NAT)

    • Switch Configuration

    • Cisco Packet Tracer

    • End Devices: 5 PCs (PC0, PC1, PC2, PC3, PC4), 2 IP Phones (IP Phone 0, IP Phone 1), 1 Server (Google Server), 1 Wireless Laptop

    • Network Devices: 3 Switches (Core Switch, Access Switch 1, Access Switch 2), 2 Routers (ISP Router, Internet Backbone)

    • Cables: Copper Straight-Through Cables, Single Mode Fiber Cable

    • Switch Configuration: VLANs were successfully created on each switch to divide a physical network into multiple virtual or logical networks

    • Successful Inter-VLAN Routing: PCs in different VLANs and sub-interfaces were able to ping and receive replies from each other

    • DHCP Assignment: After configuring DHCP pools on the ISP Router to enable automatic assignment of IP addresses, all the devices succeeded in fully making use of this deployment

    • NAT Employment: The implementation of NAT demonstrated the devices’ ability to use a single public IP to access the Internet and control traffic, as represented by the Internet Backbone and Google Server

    • The introduction of VLANs and Inter-VLAN Routing adds the convenience of less hardware, space, and cost, as it provides a logical avenue for a single hardware device to be split into several networks while being able to contact devices across divisions

    • Just a single misconfiguration can cause a breakdown in communication such as IP address (DHCP) conflicts from not excluding static addresses

Core Switch Configuration

  • After connecting all the devices, click the core switch, go to CLI, and enter the en and conf t commands to change the device hostname from Multilayer Switch 0 to Core Switch using the hostname command: hostname CoreSwitch

  • Create VLANs for regular office staff, HR, IT, and Voice by running the vlan and name commands for each VLAN, respectively. For example, vlan 10 followed by name Office

  • Configure trunk ports for each access switch; for example, int gi1/0/1, switchport mode trunk, switchport trunk allowed vlan all, then type wr

internet backbone and google Server configuration

  • Click on Internet Backbone, go to CLI, enter global configuration mode, type int loopback 0, then ip address 8.8.8.8 255.255.255.255 to simulate the public internet

  • Go to the ISP Router; in the terminal, run ip route 0.0.0.0 0.0.0.0 8.8.8.8 to handle the internet traffic default pathway

  • Google Server and assign a public static IP address by going to Desktop, then IP Configuration, check that the ip address is 8.8.8.8

  • Go to Services, select HTTPS DNS, turn it on, type in the specific web address such as, ://google.com, enter the server’s IP address, and select Add

access Switch 1 Configuration

  • On Switch0, enter global configuration mode, change the hostname to Access Switch 1, and create VLANs 10, 20, and 40

  • Configure the switch port (uplink) connected to the core switch to trunk mode by running the following commands consecutively: int gi0/1, switchport mode trunk, switchport trunk allowed vlan 10, 20, 40

  • For the computers on VLAN 10, assign access and voice ports via int range fa0/1-5, switchport mode access, switchport access vlan 10, switchport voice vlan 40

  • For the HR computers on VLAN 20, assign access and voice ports by using int range fa0/6-10, switchport mode access, switchport access vlan 20, switchport voice vlan 40, and wr

access Switch 2 Configuration

  • Click Switch1, change the name to Access Switch 2, and create VLAN 30 for IT

  • Configure the uplink as a trunk, assign access and voice ports to VLAN 30, and save the configuration

ISP Router Configuration for dhcp and inter-vlan routing

  • On Access Switch 2, configure a trunk port for the ISP Router using the port connected to the router from the core switch: int g1/0/3, switchport mode trunk, switchport trunk allowed vlan all

  • On Router-0, change the hostname to ISP Router and create sub-interfaces for each VLAN, e.g.: int gi0/0.10, encapsulation dot1Q 10, ip address 192.168.10.1 255.255.255.0, exit

  • Enable the router’s interface connected to the core switch by typing int gi0/0, no shut, and save the configuration

  • Exclude static sub-interface IP addresses: e.g., ip dhcp excluded-address 192.168.10.1

  • Configure DHCP pools: ip dhcp pool Office_Pool, network 192.168.10.0 255.255.255.0, default-router 192.168.10.1, exit

Access point and Laptop configuration

  • Click on Access Point0, go to the Config tab, navigate to Port 1, set a network name (VLAN10-WiFi), and enter a WPA2-PSK passphrase

  • Go to Access Switch 2, and in CLI connect the switch port connected to the access point by creating VLAN 10 and entering: en, conf t, int fa0/3, switchport mode access, switchport access vlan 10, no shut, exit, and wr

  • Click on the laptop and select the Config tab, turn off the laptop, and replace the existing wired module with the wireless (WPC300N) module

  • Turn the laptop on, select the Desktop tab, open PC Wireless, and connect it

NAT and ACCESS LIst configuration

  • Configure Network Address Translation (NAT) on the ISP Router by defining the outside and inside interfaces: e.g. it gi0/1, ip nat outside, exit & int gi0/0.10, ip nat inside, exit

  • Create an access list for the internal subnets: e.g., access-list 1 permit 192.168.10.0 0.0.0.255

  • Enable NAT Overload or PAT: ip nat inside source list 1 int gi0/1 overload, exit, wr

  • Check the DHCP assignment on each PC, ping among PCs to check connectivity, and ping the server to test external connections