Cisco – Basic Hands-On Lab

 

Overview & Purpose

This configuration includes setting the hostname, enabling SSH, configuring interfaces, setting up DHCP, and ensuring internet access and inter-LAN communication.

Objectives

1. Will understand the basic of Cisco configuration 

2. Self-taught before production hands-on.

LAB Topology

Here is the lab topology

Step 1: Access the Router

Connect to your Cisco router via console or any other method and enter global configuration mode:

Router> enable

Router# configure terminal

Step 2: Set the Hostname

Set the router hostname to RTR-01:

Router(config)# hostname RTR-01

Step 3: Configure SSH and Secure Login

Enable SSH for secure remote access and configure the login credentials:

RTR-01(config)# ip domain-name example.com RTR-01(config)# crypto key generate rsa RTR-01(config)# username admin privilege 15 secret YourSecurePassword RTR-01(config)# line vty 0 4 RTR-01(config-line)# transport input ssh RTR-01(config-line)# login local RTR-01(config-line)# exit RTR-01(config)# ip ssh version 2 RTR-01(config)# enable secret MyPassword

Step 4: Configure Interfaces

Interface GigabitEthernet 0/0 (Connected to ISP)

Configure the interface to use DHCP for the ISP connection:

RTR-01(config)# interface GigabitEthernet0/0 RTR-01(config-if)# description Connected to the ISP RTR-01(config-if)# ip address dhcp RTR-01(config-if)# no shutdown RTR-01(config-if)# exit

Interface GigabitEthernet 0/1 (Connected to LAN 1)

Configure the interface for the 172.16.22.0/24 network:

RTR-01(config)# interface GigabitEthernet0/1 RTR-01(config-if)# description Connected to LAN 1 RTR-01(config-if)# ip address 172.16.22.1 255.255.255.0 RTR-01(config-if)# no shutdown RTR-01(config-if)# exit

Interface GigabitEthernet 0/2 (Connected to LAN 2)

Configure the interface for the 172.16.10.0/24 network:

RTR-01(config)# interface GigabitEthernet0/2 RTR-01(config-if)# description Connected to LAN 2 RTR-01(config-if)# ip address 172.16.10.1 255.255.255.0 RTR-01(config-if)# no shutdown RTR-01(config-if)# exit

Step 5: Configure DHCP for Both Networks

Set up DHCP pools for both LANs:

DHCP for LAN 1 (172.16.22.0/24)

RTR-01(config)# ip dhcp pool LAN1 RTR-01(dhcp-config)# network 172.16.22.0 255.255.255.0 RTR-01(dhcp-config)# default-router 172.16.22.1 RTR-01(dhcp-config)# dns-server 8.8.8.8 8.8.4.4 RTR-01(dhcp-config)# exit

DHCP for LAN 2 (172.16.10.0/24)

RTR-01(config)# ip dhcp pool LAN2 RTR-01(dhcp-config)# network 172.16.10.0 255.255.255.0 RTR-01(dhcp-config)# default-router 172.16.10.1 RTR-01(dhcp-config)# dns-server 8.8.8.8 8.8.4.4 RTR-01(dhcp-config)# exit

Step 6: Enable NAT for Internet Access

Configure NAT to allow clients on both LANs to access the internet:

RTR-01(config)# access-list 1 permit 172.16.22.0 0.0.0.255 RTR-01(config)# access-list 1 permit 172.16.10.0 0.0.0.255 RTR-01(config)# interface GigabitEthernet0/0 RTR-01(config-if)# ip nat outside RTR-01(config-if)# exit RTR-01(config)# interface GigabitEthernet0/1 RTR-01(config-if)# ip nat inside RTR-01(config-if)# exit RTR-01(config)# interface GigabitEthernet0/2 RTR-01(config-if)# ip nat inside RTR-01(config-if)# exit RTR-01(config)# ip nat inside source list 1 interface GigabitEthernet0/0 overload

Step 7: Enable Inter-LAN Communication

By default, the router will allow communication between the two LANs since they are directly connected to the router. No additional configuration is required unless you want to restrict traffic (e.g., using ACLs). 

Now set both clients IP as dhcp by running the following command:

ip dhcp

The clients should fetch the IP address from the dhcp server of its own network dhcp pool server.

Step 8: Save the Configuration

Save the configuration on the router to ensure it persists after a reboot:

RTR-01(config)# end RTR-01# write memory

Step 9: Verify the Configuration

Check Interfaces

show ip interface brief

Check NAT translation

Ensure that the client IPs already on the NAT table 

show ip nat translations

Check DHCP Leases

This will show the connected DHCP IPs of every connected user. 

show ip dhcp binding

Clear IP DHCP Leases

This will clear all DHCP binding IP addresses, so next time the client reconnects and releases the IP, it will get a new IP.

clear ip dhcp binding * Or clear ip dhcp 172.16.22.3

Check Routing Table

Check the routing tables, just to ensure that the client can access to the Internet

show ip route

Test Internet Access

ping 8.8.8.8 source 172.16.22.1 ping 8.8.8.8 source 172.16.10.1

Congratulations for your first lab!