IPv4 Address Configuration, Verification, and Troubleshooting on Cisco Routers

Objective

Learn and understand how to configure and troubleshoot IPv4 addresses on Cisco routers.

Purpose

Configuring IPv4 addressing is a fundamental task for any Cisco engineer. You must also be prepared to troubleshoot incorrectly configured IPv4 addresses using appropriate show commands.

Lab Topology

Use the following topology to complete this lab exercise:

Router Setup 1

Task 1: Configure Hostnames

Objective: Set hostnames on routers R1 and R3 as per the topology.

Configuration Steps:

Router#config t
Enter configuration commands, one per line. End with CTRL/Z.
Router(config)#hostname R1

Router#config t
Enter configuration commands, one per line. End with CTRL/Z.
Router(config)#hostname R3
R3(config)#

Task 2: Configure Serial and Loopback Interfaces

Objective: Configure R1 S0/0/0 (DCE) to provide a clock of clock rate 250 Kbps to R3 and set IP addresses on Serial and Loopback interfaces.

Configuration Steps:

R1(config)#interface s0/0/0
R1(config-if)#ip address 172.16.1.1 255.255.255.192
R1(config-if)#clock rate 250000
R1(config-if)#no shutdown
R1(config-if)#end

R1#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]

R3(config)#interface s0/0/0
R3(config-if)#ip address 172.16.1.2 255.255.255.192
R3(config-if)#no shutdown
R3(config-if)#exit

R3(config)#interface lo10
R3(config-if)#ip address 10.10.10.3 255.255.255.128

R3(config)#interface lo20
R3(config-if)#ip address 10.20.20.3 255.255.255.240

R3(config)#interface lo30
R3(config-if)#ip address 10.30.30.3 255.255.255.248

R3#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]

Task 3: Verify Configuration

Objective: Use appropriate show commands to verify IP configurations and interface statuses.

Verification Commands:

R3#show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0     unassigned      YES unset  administratively down down
GigabitEthernet0/1     unassigned      YES unset  administratively down down
GigabitEthernet0/2     unassigned      YES unset  administratively down down
Serial0/0/0            172.16.1.2      YES manual up                    up
Serial0/0/1            unassigned      YES unset  administratively down down
Loopback10             10.10.10.3      YES manual up                    up
Loopback20             10.20.20.3      YES manual up                    up
Loopback30             10.30.30.3      YES manual up                    up
Vlan1                  unassigned      YES unset  administratively down down

R3#show interface s0/0/0
Serial0/0/0 is up, line protocol is up (connected)
  Hardware is HD64570
  Internet address is 172.16.1.2/26
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/0/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 1158 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

R3#

Cisco Packet Tracer file:
Load and open the .pkt Lab file in Cisco Packet Tracer from here: IPv4_Address_Configuration.pkt