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Basic Cisco Router Configuration Guide

This tutorial covers the essentials of configuring a Cisco router for a CCNA-level routing and switching environment. It includes initial setup, interface configuration, and setting up routing protocols.

Accessing the Router

  1. Connect to the Router: Use a console cable to connect your computer to the router's console port. Use terminal emulation software (like PuTTY or Tera Term) to access the router's command line interface (CLI).

  2. Enter Global Configuration Mode: After accessing the CLI, enter the global configuration mode to make changes to the router's configuration:

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

Basic Configuration

  1. Set Hostname: Assign a hostname to the router for easy identification:
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Router(config)# hostname MyRouter
MyRouter(config)#

  1. Secure Access: Configure a secret password to secure privileged EXEC mode access:

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    MyRouter(config)# enable secret mySecretPassword

Optionally, set a password for console access:

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MyRouter(config)# line console 0
MyRouter(config-line)# password consolePassword
MyRouter(config-line)# login
MyRouter(config-line)# exit
  1. Configure Interfaces: Assign IP addresses to the router's interfaces and bring them up:
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MyRouter(config)# interface GigabitEthernet0/0
MyRouter(config-if)# ip address 192.168.1.1 255.255.255.0
MyRouter(config-if)# no shutdown
MyRouter(config-if)# exit

Repeat these steps for other interfaces as needed, adjusting the interface identifiers and IP addresses according to your network design.

  1. Save Configuration: To save your configuration to the startup configuration file:
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MyRouter(config)# exit
MyRouter# copy running-config startup-config

Setting Up Routing

  1. Static Routing: For a simple network, you can set up static routing by specifying a destination network and the next-hop address or exit interface:
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MyRouter(config)# ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/1

This command sets a default route, directing all unknown traffic to the next hop specified by the GigabitEthernet0/1 interface.

  1. Dynamic Routing:

EIGRP Configuration

Enable EIGRP:

Specify the EIGRP autonomous system number. This number must match across all routers in the EIGRP domain.


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RouterA(config)# router eigrp 1
Advertise Networks:

Use the network command to specify which networks to advertise via EIGRP.

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RouterA(config-router)# network 192.168.1.0 0.0.0.255
RouterA(config-router)# network 10.1.1.0 0.0.0.255
Optional: Configure EIGRP for IPv6 (if required):

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RouterA(config)# ipv6 router eigrp 1
RouterA(config-rtr)# eigrp router-id 1.1.1.1
RouterA(config-rtr)# no shutdown
RouterA(config)# interface GigabitEthernet0/0
RouterA(config-if)# ipv6 eigrp 1
OSPF Configuration

  • Enable OSPF:

  • Define the OSPF process ID and router ID.

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RouterA(config)# router ospf 1
RouterA(config-router)# router-id 1.1.1.1
Advertise Networks:

Use the network command to advertise networks, specifying the area.

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RouterA(config-router)# network 192.168.1.0 0.0.0.255 area 0
RouterA(config-router)# network 10.1.1.0 0.0.0.255 area 0
Optional: Configure OSPF for IPv6 (if required):

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RouterA(config)# ipv6 router ospf 1
RouterA(config-rtr)# router-id 1.1.1.1
RouterA(config)# interface GigabitEthernet0/0
RouterA(config-if)# ipv6 ospf 1 area 0
Verifying Configuration

After configuring the router, use various show commands to verify the setup and the operation of the dynamic routing protocols. For EIGRP:

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RouterA# show ip eigrp neighbors
RouterA# show ip eigrp topology
For OSPF:

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RouterA# show ip ospf neighbor
RouterA# show ip route ospf

Best Practices

  • Security: Always change default passwords and consider implementing additional security features such as ACLs (Access Control Lists).
  • Backup Configuration: Regularly backup your router's configuration to avoid data loss.
  • Firmware Updates: Keep your router's firmware up to date to ensure you have the latest features and security patches.

This guide provides a foundation for configuring a Cisco router in a CCNA routing and switching context. For more detailed configurations and advanced features, refer to Cisco's official documentation and CCNA study resources.