2.4.1.5 Lab – Troubleshooting Basic PPP with Authentication (Instructor Version)
Instructor Note: Red font color or gray highlights indicate text that appears in the instructor copy only.
Topology
Addressing Table
| Device | Interface | IP Address | Subnet Mask | Default Gateway |
|---|---|---|---|---|
| R1 | G0/1 | 192.168.1.1 | 255.255.255.0 | N/A |
| S0/0/0 (DCE) | 192.168.12.1 | 255.255.255.252 | N/A | |
| S0/0/1 | 192.168.13.1 | 255.255.255.252 | N/A | |
| R2 | Lo0 | 209.165.200.225 | 255.255.255.252 | N/A |
| S0/0/0 | 192.168.12.2 | 255.255.255.252 | N/A | |
| S0/0/1 (DCE) | 192.168.23.1 | 255.255.255.252 | N/A | |
| R3 | G0/1 | 192.168.3.1 | 255.255.255.0 | N/A |
| S0/0/0 (DCE) | 192.168.13.2 | 255.255.255.252 | N/A | |
| S0/0/1 | 192.168.23.2 | 255.255.255.252 | N/A | |
| PC-A | NIC | 192.168.1.3 | 255.255.255.0 | 192.168.1.1 |
| PC-C | NIC | 192.168.3.3 | 255.255.255.0 | 192.168.3.1 |
Objectives
Part 1: Build the Network and Load Device Configurations
Part 2: Troubleshoot the Data Link Layer
Part 3: Troubleshoot the Network Layer
Background / Scenario
The routers at your company were configured by an inexperienced network engineer. Several errors in the configuration have resulted in connectivity issues. Your manager has asked you to troubleshoot and correct the configuration errors and document your work. Using your knowledge of PPP and standard testing methods, find and correct the errors. Ensure that all of the serial links use PPP CHAP authentication, and that all of the networks are reachable.
Note: The routers used with CCNA hands-on labs are Cisco 1941 Integrated Services Routers (ISRs) with Cisco IOS Release 15.2(4)M3 (universalk9 image). The switches used are Cisco Catalyst 2960s with Cisco IOS Release 15.0(2) (lanbasek9 image). Other routers, switches, and Cisco IOS versions can be used. Depending on the model and Cisco IOS version, the commands available and output produced might vary from what is shown in the labs. Refer to the Router Interface Summary Table at the end of this lab for the correct interface identifiers.
Note: Make sure that the routers and switches have been erased and have no startup configurations. If you are unsure, contact your instructor.
Instructor Note: Refer to the Instructor Lab Manual for the procedures to initialize and reload devices.
Required Resources
- 3 Routers (Cisco 1941 with Cisco IOS Release 15.2(4)M3 universal image or comparable)
- 2 Switches (Cisco 2960 with Cisco IOS Release 15.0(2) lanbasek9 image or comparable)
- 2 PCs (Windows with a terminal emulation program, such as Tera Term)
- Console cables to configure the Cisco IOS devices via the console ports
- Ethernet and serial cables as shown in the topology
Part 1: Build the Network and Load Device Configurations
In Part 1, you will set up the network topology, configure basic settings on the PC hosts, and load configurations on the routers.
Step 1: Cable the network as shown in the topology.
Step 2: Configure the PC hosts.
Step 3: Load router configurations.
Load the following configurations into the appropriate router. All routers have the same passwords. The privileged EXEC mode password is class. The password for console and vty access is cisco. All serial interfaces should be configured with PPP encapsulation and authenticated with CHAP using the password of chap123.
Router R1 Configuration:
hostname R1 enable secret class no ip domain lookup banner motd #Unauthorized Access is Prohibited!# username R2 password chap123 username R3 password chap123 interface g0/1 ip address 192.168.1.1 255.255.255.0 no shutdown interface s0/0/0 ip address 192.168.12.1 255.255.255.252 clock rate 128000 encapsulation ppp ppp authentication chap ! no shutdown interface s0/0/1 ip address 192.168.31.1 255.255.255.252 ! ip address 192.168.13.1 255.255.255.252 encapsulation ppp ppp authentication pap ! ppp authentication chap ! no shutdown exit router ospf 1 router-id 1.1.1.1 network 192.168.1.0 0.0.0.255 area 0 network 192.168.12.0 0.0.0.3 area 0 network 192.168.13.0 0.0.0.3 area 0 passive-interface g0/1 exit line con 0 password cisco logging synchronous login line vty 0 4 password cisco login
Router R2 Configuration:
hostname R2 enable secret class no ip domain lookup banner motd #Unauthorized Access is Prohibited!# username R1 password chap123 username r3 password chap123 ! username R3 password chap123 ! no username r3 password chap123 interface lo0 ip address 209.165.200.225 255.255.255.252 interface s0/0/0 ip address 192.168.12.2 255.255.255.252 encapsulation ppp ppp authentication chap no shutdown interface s0/0/1 ip address 192.168.23.1 255.255.255.252 clock rate 128000 ! encapsulation ppp ! ppp authentication chap no shutdown exit router ospf 1 router-id 2.2.2.2 network 192.168.12.0 0.0.0.3 area 0 network 192.168.23.0 0.0.0.3 area 0 default-information originate exit ip route 0.0.0.0 0.0.0.0 loopback0 line con 0 password cisco logging synchronous login line vty 0 4 password cisco login
Router R3 Configuration:
hostname R3 enable secret class no ip domain lookup banner motd #Unauthorized Access is Prohibited!# username R2 password chap123 username R3 password chap123 !no username R3 password chap123 !username R1 password chap123 interface g0/1 ip address 192.168.3.1 255.255.255.0 no shutdown interface s0/0/0 ip address 192.168.13.2 255.255.255.252 clock rate 128000 encapsulation ppp ppp authentication chap no shutdown interface s0/0/1 ip address 192.168.23.2 255.255.255.252 encapsulation ppp ppp authentication chap no shutdown exit router ospf 1 router-id 3.3.3.3 ! network 192.168.3.0 0.0.0.255 area 0 network 192.168.13.0 0.0.0.3 area 0 network 192.168.23.0 0.0.0.3 area 0 passive-interface g0/1 line con 0 password cisco logging synchronous login line vty 0 4 password cisco login
Step 4: Save your running configuration.
Part 2: Troubleshoot the Data Link Layer
In Part 2, you will use show commands to troubleshoot data link layer issues. Be sure to verify settings, such as clock rate, encapsulation, CHAP, and usernames/passwords.
Step 1: Examine the R1 configuration.
a. Use the show interfaces command to determine whether PPP has been established on both serial links.
R1# show interfaces s0/0/0
Serial0/0/0 is administratively down, line protocol is down
Hardware is GT96K Serial
Internet address is 192.168.12.1/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Closed, loopback not set
Keepalive set (10 sec)
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:04:41
Input queue: 0/75/0/0 (size/max/drops/flushes); 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, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=down DTR=up RTS=down CTS=down
R1# show interfaces s0/0/1
Serial0/0/1 is administratively down, line protocol is down
Hardware is GT96K Serial
Internet address is 192.168.31.1/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Closed, loopback not set
Keepalive set (10 sec)
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:09:10
Input queue: 0/75/0/0 (size/max/drops/flushes); 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, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=up DTR=down RTS=down CTS=down
From the show interfaces results for S0/0/0 and S0/0/1, what are possible issues with the PPP links?
____________________________________________________
The output indicates: Both S0/0/0 and S0/0/1 are shut down. PPP encapsulation has been applied to both S0/0/0 and S0/0/1 interfaces. Besides the fact that the serial interface are administratively down, there are still issues with the PPP configurations, such as mismatched authentication.
b. Use the debug ppp authentication command to view real-time PPP authentication output during troubleshooting.
R1# debug ppp authentication PPP authentication debugging is on
c. Use the show run interface s0/0/0 command to examine the settings on S0/0/0.
R1# show run interface s0/0/0 Building configuration... Current configuration : 143 bytes ! interface Serial0/0/0 ip address 192.168.12.1 255.255.255.252 encapsulation ppp shutdown ppp authentication chap clock rate 128000 end
Resolve all problems found for S0/0/0. Record the commands used to correct the configuration.
______________________________________________________
R1(config)# interface s0/0/0
R1(config-if)# no shutdown
After correcting the issue, what information does the debug output provide?
R1(config-if)# no shutdown *Jun 18 12:01:23.931: %LINK-3-UPDOWN: Interface Serial0/0/0, changed state to up *Jun 18 12:01:23.931: Se0/0/0 PPP: Using default call direction *Jun 18 12:01:23.931: Se0/0/0 PPP: Treating connection as a dedicated line *Jun 18 12:01:23.931: Se0/0/0 PPP: Session handle[F900005A] Session id[90] *Jun 18 12:01:23.943: Se0/0/0 CHAP: O CHALLENGE id 1 len 23 from "R1" *Jun 18 12:01:23.947: Se0/0/0 CHAP: I CHALLENGE id 1 len 23 from "R2" *Jun 18 12:01:23.947: Se0/0/0 PPP: Sent CHAP SENDAUTH Request *Jun #18 12:01:23.947: Se0/0/0 PPP: Received SENDAUTH Response PASS *Jun 18 12:01:23.947: Se0/0/0 CHAP: Using hostname from configured hostname *Jun 18 12:01:23.947: Se0/0/0 CHAP: Using password from AAA *Jun 18 12:01:23.947: Se0/0/0 CHAP: O RESPONSE id 1 len 23 from "R1" *Jun 18 12:01:23.947: Se0/0/0 CHAP: I RESPONSE id 1 len 23 from "R2" *Jun 18 12:01:23.951: Se0/0/0 PPP: Sent CHAP LOGIN Request *Jun 18 12:01:23.951: Se0/0/0 PPP: Received LOGIN Response PASS *Jun 18 12:01:23.951: Se0/0/0 CHAP: O SUCCESS id 1 len 4 *Jun 18 12:01:23.951: Se0/0/0 CHAP: I SUCCESS id 1 len 4
_____________________________________________________
The debug output shows a successful CHAP negotiation process. PPP has been established on the link connecting R1 S0/0/0 and R2 S0/0/0.
d. Use the show run interface s0/0/1 command to examine the settings on S0/0/1.
R1# show run interface s0/0/1
Building configuration…
Current configuration : 123 bytes
!
interface Serial0/0/1
ip address 192.168.31.1 255.255.255.252
encapsulation ppp
shutdown
ppp authentication pap
end
Resolve all problems found for S0/0/1. Record the commands used to correct the configuration.
_______________________________________________________
R1(config)# interface s0/0/1
R1(config-if)# ppp authentication chap
R1(config-if)# no shutdown
After correcting the issue, what information does the debug output provide?
*Jun 18 12:13:57.819: %LINK-3-UPDOWN: Interface Serial0/0/1, changed state to up *Jun 18 12:13:57.819: Se0/0/1 PPP: Using default call direction *Jun 18 12:13:57.819: Se0/0/1 PPP: Treating connection as a dedicated line *Jun 18 12:13:57.819: Se0/0/1 PPP: Session handle[F300005B] Session id[91] *Jun 18 12:13:57.831: Se0/0/1 CHAP: O CHALLENGE id 1 len 23 from "R1" *Jun 18 12:13:57.831: Se0/0/1 CHAP: I CHALLENGE id 1 len 23 from "R3" *Jun 18 12:13:57.831: Se0/0/1 PPP: Sent CHAP SENDAUTH Request *Jun 18 12:13:57.831: Se0/0/1 PPP: Received SENDAUTH Response PASS *Jun 18 12:13:57.831: Se0/0/1 CHAP: Using hostname from configured hostname *Jun 18 12:13:57.831: Se0/0/1 CHAP: Using password from AAA *Jun 18 12:13:57.831: Se0/0/1 CHAP: O RESPONSE id 1 len 23 from "R1" *Jun 18 12:14:01.819: Se0/0/1 PPP: Using default call direction *Jun 18 12:14:01.819: Se0/0/1 PPP: Treating connection as a dedicated line *Jun 18 12:14:01.819: Se0/0/1 PPP: Session handle[BC00005C] Session id[92] *Jun 18 12:14:01.831: Se0/0/1 CHAP: O CHALLENGE id 1 len 23 from "R1" *Jun 18 12:14:01.851: Se0/0/1 CHAP: I CHALLENGE id 1 len 23 from "R3" *Jun 18 12:14:01.851: Se0/0/1 PPP: Sent CHAP SENDAUTH Request *Jun 18 12:14:01.851: Se0/0/1 PPP: Sending AAA radius abort R1(config-if)# *Jun 18 12:14:04.860: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1, changed state to up *Jun 18 12:14:04.868: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1, changed state to down *Jun 18 12:14:06.856: Se0/0/1 PPP: Using default call direction
_____________________________________________________
The debug output shows an unsuccessful CHAP negotiation process and the interface is going up and down. More configuration errors exist for the link connecting R1 S0/0/1 and R3 S0/0/0.
e. Use the no debug ppp authentication or undebug all command to turn off the debug PPP output.
f. Use the show running-config | include username command to verify the correct username and password configurations.
R1# show running-config | include username username R2 password 0 chap123 username R3 password 0 chap123
Resolve all problems found. Record the commands used to correct the configuration.
______________________________________________________
No problems exist.
Step 2: Examine the R2 configuration.
a. Use the show interfaces command to determine if PPP has been established on both serial links.
R2# show interfaces s0/0/0
Serial0/0/0 is up, line protocol is up
Hardware is GT96K Serial
Internet address is 192.168.12.2/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:06, output 00:00:01, output hang never
Last clearing of "show interface" counters 00:18:22
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (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
53 packets input, 3055 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
52 packets output, 2772 bytes, 0 underruns
0 output errors, 0 collisions, 34 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
1 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
R2# show interfaces s0/0/1
Serial0/0/1 is up, line protocol is down
Hardware is GT96K Serial
Internet address is 192.168.23.1/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:11, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (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
230 packets input, 4370 bytes, 0 no buffer
Received 230 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
119 packets output, 3014 bytes, 0 underruns
0 output errors, 0 collisions, 42 interface resets
230 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
121 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Have all links been established? _______No
If the answer is no, which links need to be examined? What are the possible issues?
______________________________________________________
The link between R2 and R3 has not been established because S0/0/1 interface is configured with HDLC encapsulation. Beside the encapsulation issue, authentication mismatch can also prevent link establishment.
b. Use the show run interface command to examine links that have not been established.
R2# show run interface s0/0/1 Building configuration... Current configuration : 89 bytes ! interface Serial0/0/1 ip address 192.168.23.1 255.255.255.252 clock rate 128000 end
Resolve all problems found for the interfaces. Record the commands used to correct the configuration.
_______________________________________________________
R2(config)# interface s0/0/1
R2(config-if)# encapsulation ppp
R2(config-if)# ppp authentication chap
c. Use the show running-config | include username command to verify the correct username and password configurations.
R2# show running-config | include username username R1 password 0 chap123 username r3 password 0 chap123
Resolve all problems found. Record the commands used to correct the configuration.
_______________________________________________________
R2(config)# no username r3 password chap123
R2(config)# username R3 password chap123
d. Use the show ppp interface serial command for the serial interface that you are troubleshooting.
R2# show interfaces s0/0/1
Serial0/0/1 is up, line protocol is up
Hardware is GT96K Serial
Internet address is 192.168.23.1/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:07, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:25:09
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (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
506 packets input, 27348 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
507 packets output, 28030 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Has the link been established? ______Yes
Step 3: Examine the R3 configuration.
a. Use the show interfaces command to determine whether PPP has been established on both serial links.
R3# show interfaces s0/0/0
Serial0/0/0 is up, line protocol is down
Hardware is GT96K Serial
Internet address is 192.168.13.2/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Closed, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:01, output 00:00:01, output hang never
Last clearing of "show interface" counters 00:55:56
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
5 minute input rate 0 bits/sec, 3 packets/sec
5 minute output rate 0 bits/sec, 2 packets/sec
3540 packets input, 70800 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
3274 packets output, 60079 bytes, 0 underruns
0 output errors, 0 collisions, 821 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
1573 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
R3# show interfaces s0/0/1
Serial0/0/1 is up, line protocol is up
Hardware is GT96K Serial
Internet address is 192.168.23.2/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:07, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:51:19
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (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
711 packets input, 35022 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
847 packets output, 36444 bytes, 0 underruns
0 output errors, 0 collisions, 73 interface resets
141 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
96 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Have all links been established? ________No
If the answer is no, which links need to be examined? What are the possible issues?
_______________________________________________________
The serial link between R1 and R3 has not been established. Serial0/0/0 is configured with PPP encapsulation, and the interface is enabled. Therefore, the possible issue is authentication mismatch.
b. Using the show run interface command to examine on any serial link that has not been established.
R3# show run interface s0/0/0 Building configuration... Current configuration : 134 bytes ! interface Serial0/0/0 ip address 192.168.13.2 255.255.255.252 encapsulation ppp ppp authentication chap clock rate 2000000 end
Resolve all problems found on the interfaces. Record the commands used to correct the configuration.
_______________________________________________________
No problems exist with the S0/0/0 configuration.
c. Use the show running-config | include username command to verify the correct username and password configurations.
R3# show run | include username username R2 password 0 chap123 username R3 password 0 chap123
Resolve all problems found. Record the commands used to correct the configuration.
_____________________________________________________
R3(config)# no username R3 password chap123
R3(config)# username R1 password chap123
d. Use the show interface command to verify that serial links have been established.
R3# show interface s0/0/0
Serial0/0/0 is up, line protocol is up
Hardware is GT96K Serial
Internet address is 192.168.13.2/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
CRC checking enabled
Last input 00:00:20, output 00:00:03, output hang never
Last clearing of "show interface" counters 01:03:35
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (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
4392 packets input, 88310 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
3974 packets output, 74268 bytes, 0 underruns
0 output errors, 0 collisions, 994 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
1919 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
e. Have all PPP links been established?________Yes
f. Can PC-A ping Lo0? _______Yes
g. Can PC-A ping PC-C? ________No
Note: It may be necessary to disable the PC firewall for pings between the PCs to succeed.
Part 3: Troubleshoot the Network Layer
In Part 3, you will verify that Layer 3 connectivity is established on all interfaces by examining IPv4 and OSPF configurations.
Step 1: Verify that the interfaces listed in the Addressing Table are active and configured with the correct IP address information.
Issue the show ip interface brief command on all routers to verify that the interfaces are in an up/up state.
R1# show ip interface brief
Interface IP-Address OK? Method Status Protocol
Embedded-Service-Engine0/0 unassigned YES unset administratively down down
GigabitEthernet0/0 unassigned YES unset administratively down down
GigabitEthernet0/1 192.168.1.1 YES manual up up
Serial0/0/0 192.168.12.1 YES manual up up
Serial0/0/1 192.168.31.1 YES manual up up
R2# show ip interface brief
Interface IP-Address OK? Method Status Protocol
Embedded-Service-Engine0/0 unassigned YES unset administratively down down
GigabitEthernet0/0 unassigned YES unset administratively down down
GigabitEthernet0/1 unassigned YES unset administratively down down
Serial0/0/0 192.168.12.2 YES manual up up
Serial0/0/1 192.168.23.1 YES manual up up
Loopback0 209.165.200.225 YES manual up up
R3# show ip interface brief
Interface IP-Address OK? Method Status Protocol
Embedded-Service-Engine0/0 unassigned YES unset administratively down down
GigabitEthernet0/0 unassigned YES unset administratively down down
GigabitEthernet0/1 192.168.3.1 YES manual up up
Serial0/0/0 192.168.13.2 YES manual up up
Serial0/0/1 192.168.23.2 YES manual up up
Resolve all problems found. Record the commands used to correct the configuration.
________________________________________________________
R1(config)# interface s0/0/1
R1(config-if)# ip address 192.168.13.1 255.255.255.252
Step 2: Verify OSPF Routing
Issue the show ip protocols command to verify that OSPF is running and that all networks are advertised.
R1# show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.1.0 0.0.0.255 area 0
192.168.12.0 0.0.0.3 area 0
192.168.13.0 0.0.0.3 area 0
Passive Interface(s):
GigabitEthernet0/1
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 110 00:01:46
2.2.2.2 110 00:01:46
Distance: (default is 110)
R2# show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 2.2.2.2
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.12.0 0.0.0.3 area 0
192.168.23.0 0.0.0.3 area 0
209.165.200.224 0.0.0.3 area 0
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 110 00:03:53
1.1.1.1 110 00:07:45
Distance: (default is 110)
R3# show ip protocols
*** IP Routing is NSF aware ***
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 3.3.3.3
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.13.0 0.0.0.3 area 0
192.168.23.0 0.0.0.3 area 0
Passive Interface(s):
GigabitEthernet0/1
Routing Information Sources:
Gateway Distance Last Update
1.1.1.1 110 00:07:14
2.2.2.2 110 00:07:14
Distance: (default is 110)
Resolve all problems found. Record the commands used to correct the configuration.
_____________________________________________________
R3(config)# router ospf 1
R3(config-router)# network 192.168.3.0 0.0.0.255 area 0
Can PC-A ping PC-C? _____Yes
If connectivity does not exist between all hosts, then continue troubleshooting to resolve any remaining issues.
Note: It may be necessary to disable the PC firewall for pings between the PCs to succeed.
Router Interface Summary Table
| Router Interface Summary | ||||
|---|---|---|---|---|
| Router Model | Ethernet Interface #1 | Ethernet Interface #2 | Serial Interface #1 | Serial Interface #2 |
| 1800 | Fast Ethernet 0/0 (F0/0) | Fast Ethernet 0/1 (F0/1) | Serial 0/0/0 (S0/0/0) | Serial 0/0/1 (S0/0/1) |
| 1900 | Gigabit Ethernet 0/0 (G0/0) | Gigabit Ethernet 0/1 (G0/1) | Serial 0/0/0 (S0/0/0) | Serial 0/0/1 (S0/0/1) |
| 2801 | Fast Ethernet 0/0 (F0/0) | Fast Ethernet 0/1 (F0/1) | Serial 0/1/0 (S0/1/0) | Serial 0/1/1 (S0/1/1) |
| 2811 | Fast Ethernet 0/0 (F0/0) | Fast Ethernet 0/1 (F0/1) | Serial 0/0/0 (S0/0/0) | Serial 0/0/1 (S0/0/1) |
| 2900 | Gigabit Ethernet 0/0 (G0/0) | Gigabit Ethernet 0/1 (G0/1) | Serial 0/0/0 (S0/0/0) | Serial 0/0/1 (S0/0/1) |
| Note: To find out how the router is configured, look at the interfaces to identify the type of router and how many interfaces the router has. There is no way to effectively list all the combinations of configurations for each router class. This table includes identifiers for the possible combinations of Ethernet and Serial interfaces in the device. The table does not include any other type of interface, even though a specific router may contain one. An example of this might be an ISDN BRI interface. The string in parenthesis is the legal abbreviation that can be used in Cisco IOS commands to represent the interface. | ||||
Device Configs – Final
Router R1
R1#show run Building configuration... Current configuration : 1821 bytes ! version 15.2 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R1 ! boot-start-marker boot-end-marker ! enable secret 4 06YFDUHH61wAE/kLkDq9BGho1QM5EnRtoyr8cHAUg.2 ! no aaa new-model memory-size iomem 15 ! ip cef ! no ip domain lookup no ipv6 cef multilink bundle-name authenticated ! username R2 password 0 chap123 username R3 password 0 chap123 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 no ip address shutdown duplex auto speed auto ! interface GigabitEthernet0/1 ip address 192.168.1.1 255.255.255.0 duplex auto speed auto ! interface Serial0/0/0 ip address 192.168.12.1 255.255.255.252 encapsulation ppp ppp authentication chap clock rate 128000 ! interface Serial0/0/1 ip address 192.168.13.1 255.255.255.252 encapsulation ppp ppp authentication chap ! router ospf 1 router-id 1.1.1.1 passive-interface GigabitEthernet0/1 network 192.168.1.0 0.0.0.255 area 0 network 192.168.12.0 0.0.0.3 area 0 network 192.168.13.0 0.0.0.3 area 0 ! ip forward-protocol nd ! no ip http server no ip http secure-server ! control-plane ! banner motd ^CUnauthorized Access is Prohibited!^C ! line con 0 password cisco logging synchronous login line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line vty 0 4 password cisco login transport input all ! scheduler allocate 20000 1000 ! end
Router R2
R2#show run Building configuration... Current configuration : 1866 bytes ! version 15.2 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R2 ! boot-start-marker boot-end-marker ! enable secret 4 06YFDUHH61wAE/kLkDq9BGho1QM5EnRtoyr8cHAUg.2 ! no aaa new-model memory-size iomem 15 ! ip cef ! no ip domain lookup no ipv6 cef multilink bundle-name authenticated ! username R1 password 0 chap123 username R3 password 0 chap123 ! interface Loopback0 ip address 209.165.200.225 255.255.255.252 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 no ip address shutdown duplex auto speed auto ! interface GigabitEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 ip address 192.168.12.2 255.255.255.252 encapsulation ppp ppp authentication chap ! interface Serial0/0/1 ip address 192.168.23.1 255.255.255.252 encapsulation ppp ppp authentication chap clock rate 128000 ! router ospf 1 router-id 2.2.2.2 network 192.168.12.0 0.0.0.3 area 0 network 192.168.23.0 0.0.0.3 area 0 default-information originate ! ip forward-protocol nd ! no ip http server no ip http secure-server ! ip route 0.0.0.0 0.0.0.0 Loopback0 ! control-plane ! banner motd ^CUnauthorized Access is Prohibited!^C ! line con 0 password cisco logging synchronous login line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line vty 0 4 password cisco login transport input all ! scheduler allocate 20000 1000 ! end
Router R3
R3#show run Building configuration... Current configuration : 1888 bytes ! version 15.2 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R3 ! boot-start-marker boot-end-marker ! enable secret 4 06YFDUHH61wAE/kLkDq9BGho1QM5EnRtoyr8cHAUg.2 ! no aaa new-model memory-size iomem 15 ! ip cef ! no ip domain lookup no ipv6 cef ! multilink bundle-name authenticated ! username R2 password 0 chap123 username R1 password 0 chap123 ! interface Embedded-Service-Engine0/0 no ip address shutdown ! interface GigabitEthernet0/0 no ip address shutdown duplex auto speed auto ! interface GigabitEthernet0/1 ip address 192.168.3.1 255.255.255.0 duplex auto speed auto ! interface Serial0/0/0 ip address 192.168.13.2 255.255.255.252 encapsulation ppp ppp authentication chap clock rate 128000 ! interface Serial0/0/1 ip address 192.168.23.2 255.255.255.252 encapsulation ppp ppp authentication chap ! router ospf 1 router-id 3.3.3.3 passive-interface GigabitEthernet0/1 network 192.168.3.0 0.0.0.255 area 0 network 192.168.13.0 0.0.0.3 area 0 network 192.168.23.0 0.0.0.3 area 0 ! ip forward-protocol nd ! no ip http server no ip http secure-server ! control-plane ! banner motd ^CUnauthorized Access is Prohibited!^C ! line con 0 password cisco logging synchronous login line aux 0 line 2 no activation-character no exec transport preferred none transport input all transport output pad telnet rlogin lapb-ta mop udptn v120 ssh stopbits 1 line vty 0 4 password cisco login transport input all ! scheduler allocate 20000 1000 ! end