Router Configuration Basics

Introduction to Cisco Routers

A Cisco router directs traffic between networks, like a traffic cop for your data. The Command Line Interface (CLI) is your tool to configure, monitor, and troubleshoot it—faster and more powerful than any GUI.

15 Basic Commands

1. show version

Shows software version and hardware info.

Cisco IOS Software, Version 15.1(4)M4
Router uptime is 2 days, 3 hours

2. show ip interface brief

Summarizes interface status and IPs.

Interface    IP-Address     Status    Protocol
Gi0/0        192.168.1.1    up        up
Gi0/1        unassigned     down      down

3. configure terminal

Enters configuration mode.

Router# configure terminal
Router(config)#

4. interface <interface-name>

Configures a specific interface.

Router(config)# interface GigabitEthernet0/0
Router(config-if)#

5. ip address <ip> <mask>

Sets an IP address.

Router(config-if)# ip address 192.168.1.1 255.255.255.0

6. no shutdown

Activates an interface.

Router(config-if)# no shutdown
%LINK-5-CHANGED: Interface Gi0/0, changed state to up

7. show running-config

Displays current configuration.

interface GigabitEthernet0/0
 ip address 192.168.1.1 255.255.255.0

8. show ip route

Shows the routing table.

C    192.168.1.0/24 is directly connected, Gi0/0

9. ping <ip-address>

Tests connectivity.

Router# ping 192.168.1.2
!!!!! Success rate is 100 percent (5/5)

10. traceroute <ip-address>

Traces the path to a destination.

Router# traceroute 192.168.1.2
1 192.168.1.2 1 msec

11. enable

Enters privileged mode.

Router> enable
Router#

12. reload

Reboots the router.

Router# reload
Proceed with reload? [confirm]

13. show interfaces

Details interface stats.

GigabitEthernet0/0 is up, line protocol is up
  Internet address is 192.168.1.1/24

14. show arp

Shows ARP table.

Internet  192.168.1.1  -   0012.3456.789a  Gi0/0

15. write memory

Saves configuration.

Router# write memory
Building configuration... [OK]