1-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
Lab 12.2.1.1 EIGRPTroubleshooting
F0/0 192.168.0.1/24
S0/1 192.168.112.1/24S0/0 192.168.64.1/30
S0/0 192.168.64.2/30 S0/1 192.168.112.2/24
Fa0/0 192.168.72.1/24 Fa0/0 192.168.120.1/24
SanJose1
West asman East asman
Objective
Utilize a systematic approach to troubleshoot a simple network problem.
Scenario
You have been asked to check out the Westasman, SanJose1 and Eastasman
routers. It has been determined that workstations connected to the Westasman
router cannot communicate with users on the SanJose1 or Eastasman routers.
The workstations on the Eastasman router cannot communicate with either the
Westasman or SanJose1 workstations.
Lab Tasks
Build the network according to the diagram above and load the appropriate
‘broken’ configuration files to each router. Save the configurations and reload
each router. Clock rates have been applied to all serial interfaces.
Step 1
Define your problem.
Users report that they are unable to communicate with workstations on remote
networks. Users on the same network are able to communicate with each
other.
Step 2
Gather the Facts.
2-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
Based on the current information you have, all the evidence points to a WAN
link failure. You then login to the routers to gather more information about the
problem.
Issue the following commands to narrow down your possibilities.
The first thing to check is your connections.
SanJose1#show ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.0.1 YES manual up up
Serial0/0 192.168.112.1 YES manual up up
Serial0/1 192.168.64.2 YES manual up up
Eastasman#show ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.120.1 YES manual up up
Serial0/0 192.168.112.2 YES manual up up
BRI0/0 unassigned YES unset administratively down down
BRI0/0:1 unassigned YES unset administratively down down
BRI0/0:2 unassigned YES unset administratively down down
FastEthernet0/1 unassigned YES unset administratively down down
Serial0/1 unassigned YES unset administratively down down
Westasman#show ip interface brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.72.1 YES manual up up
Serial0/0 192.168.64.1 YES manual up up
BRI0/0 unassigned YES unset administratively down down
BRI0/0:1 unassigned YES unset administratively down down
BRI0/0:2 unassigned YES unset administratively down down
Serial0/1 unassigned YES unset administratively down down
Then check the routing table to see if you have the appropriate routes. Note –
in a very large network you can enter a network number to limit the display.
SanJose1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
192.168.64.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.64.0/30 is directly connected, Serial0/1
C 192.168.64.1/32 is directly connected, Serial0/1
192.168.112.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.112.0/24 is directly connected, Serial0/0
C 192.168.112.2/32 is directly connected, Serial0/0
C 192.168.0.0/24 is directly connected, FastEthernet0/0
Eastasman#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.120.0/24 is directly connected, FastEthernet0/0
192.168.112.0/24 is variably subnetted, 2 subnets, 2 masks
3-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
C 192.168.112.0/24 is directly connected, Serial0/0
C 192.168.112.1/32 is directly connected, Serial0/0
Westasman#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.72.0/24 is directly connected, FastEthernet0/0
192.168.64.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.64.0/30 is directly connected, Serial0/0
C 192.168.64.2/32 is directly connected, Serial0/0
EIGRP log-neighbor-changes is the best tool you have to diagnose un-
stable neighbor relationships. You may want to enable it on every router in your
network. The uptime value from show ip eigrp neighbors will tell you the
last time a neighbor relationship was reset (bounced), but not how often or why.
With log-neighbor-changes on and logging buffered, you keep not only a
history of when neighbors have been reset, but the reason why.
Logging buffered is also recommended because logging to a syslog server
is dependent on the network. For example, if the neighbor bouncing is between
the router losing neighbors and the syslog server, the messages could be lost.
It may be prudent to keep these types of messages locally on the router.
It may also be useful to increase the size of the buffer log in order to capture a
greater duration of error messages. You would hate to lose the EIGRP
neighbor messages because of flapping links filling the buffer log. If your
routers have enough memory to hold the log file, change the buffer log size us-
ing the command logging buffered {value} in configuration mode.
SanJose1(config)#router eigrp 123
SanJose1(config-router)#eigrp log-neighbor-changes
SanJose1(config-router)#exit
SanJose1(config)#logging buffered 4096
02:09:15: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.64.1 (Serial0/1) is up:
new adjacency
02:09:16: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.64.1 (Serial0/1) is down:
holding time expired
02:09:16: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.112.2 (Serial0/0) is up:
new adjacency
02:09:17: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.112.2 (Serial0/0) is down:
holding time expired
02:09:24: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.64.1 (Serial0/1) is up:
new adjacency
02:09:25: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.64.1 (Serial0/1) is down:
holding time expired
02:09:25: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.112.2 (Serial0/0) is up:
new adjacency
02:09:26: %DUAL-5-NBRCHANGE: IP-EIGRP 123: Neighbor 192.168.112.2 (Serial0/0) is down:
holding time expired
Step 3
Consider the possibilities. Use the information you have and your knowledge of
Cisco products to isolate the problem.
4-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
Neighbor relationships are flapping. Possible configuration error within the rout-
ing protocol. Check routing information.
Step 4
Create an action plan.
Confirm the configuration of the EIGRP routing protocol. Change configurations
as necessary.
Step 5
Implement the action plan.
Confirm the configuration of eigrp 123 on the routers. Note – the following
command can be used to parse the output of the running configuration.
SanJose1#show run | begin router eigrp
router eigrp 123
network 192.168.0.0
network 192.168.64.0 0.0.0.3
network 192.168.112.0
no auto-summary
eigrp log-neighbor-changes
!
ip classless
no ip http server
!
banner motd ^CCLab 12-1^C
!
line con 0
password 7 030752180500
login
transport input none
line aux 0
line vty 0 4
password 7 070C285F4D06
login
!
no scheduler allocate
end
Eastasman#show run | begin router eigrp
router eigrp 123
network 192.168.112.0
network 192.168.120.0
no auto-summary
!
ip classless
no ip http server
!
banner motd ^CCLab 12-1^C
!
line con 0
password 7 110A1016141D
login
transport input none
line aux 0
line vty 0 4
password 7 14141B180F0B
login
!
!
5-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
no scheduler allocate
end
Westasman#show run | begin router eigrp
router eigrp 123
network 192.168.64.0 0.0.0.3
network 192.168.72.0
no auto-summary
!
ip classless
no ip http server
!
banner motd ^CCLab 12-1^C
!
line con 0
exec-timeout 0 0
password cisco
login
transport input none
line aux 0
line vty 0 4
password cisco
login
!
!
no scheduler allocate
end
Everything looks fine here.
Now check the hello-interval and hold-time on each interface. Note – on core
routers with long configurations, parsing output will always help to reduce the
information displayed.
SanJose1#show run interface s0/0
Building configuration
Current configuration : 179 bytes
!
interface Serial0/0
ip address 192.168.112.1 255.255.255.0
ip hello-interval eigrp 123 10
ip hold-time eigrp 123 1
encapsulation ppp
no ip mroute-cache
no fair-queue
end
SanJose1#show run interface s0/1
Building configuration
Current configuration : 145 bytes
!
interface Serial0/1
ip address 192.168.64.2 255.255.255.252
ip hello-interval eigrp 123 10
ip hold-time eigrp 123 1
encapsulation ppp
end
Westasman#show run interface s0/0
Building configuration
Current configuration:
!
interface Serial0/0
ip address 192.168.64.1 255.255.255.252
6-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
no ip directed-broadcast
ip hello-interval eigrp 123 180
ip hold-time eigrp 123 540
encapsulation ppp
no ip mroute-cache
no fair-queue
clockrate 56000
end
Eastasman#show run interface s0/0
Building configuration
Current configuration:
!
interface Serial0/0
ip address 192.168.112.2 255.255.255.0
no ip directed-broadcast
ip hello-interval eigrp 123 180
ip hold-time eigrp 123 540
encapsulation ppp
no ip mroute-cache
no fair-queue
clockrate 56000
end
Based on your knowledge of EIGRP, you know that the hello-interval and the
hold-time for the SanJose1 router is incorrectly configured. A general rule is to
set the hello-interval to 180 seconds on slow WAN links and the hold-time to 3
times the hello-interval, which would be 540 seconds.
Issue the following commands to remedy the situation.
SanJose1(config)#interface s0/0
SanJose1(config-if)#ip hello-interval eigrp 123 180
SanJose1(config-if)#ip hold-time eigrp 123 540
SanJose1(config)#interface s0/1
SanJose1(config-if)#ip hello-interval eigrp 123 180
SanJose1(config-if)#ip hold-time eigrp 123 540
Step 6
Observe the Results of the action plan.
Login to each router. Check if the routing tables are being populated properly.
Also, perform an extended ping from end to end.
Issue the show ip route command:
SanJose1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
D 192.168.72.0/24 [90/20514560] via 192.168.64.1, 00:01:00, Serial0/1
D 192.168.120.0/24 [90/20514560] via 192.168.112.2, 00:00:18, Serial0/0
192.168.64.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.64.0/30 is directly connected, Serial0/1
C 192.168.64.1/32 is directly connected, Serial0/1
192.168.112.0/24 is variably subnetted, 2 subnets, 2 masks
7-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
C 192.168.112.0/24 is directly connected, Serial0/0
C 192.168.112.2/32 is directly connected, Serial0/0
C 192.168.0.0/24 is directly connected, FastEthernet0/0
Westasman#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
C 192.168.72.0/24 is directly connected, FastEthernet0/0
D 192.168.120.0/24 [90/21026560] via 192.168.64.2, 00:01:01, Serial0/0
192.168.64.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.64.0/30 is directly connected, Serial0/0
C 192.168.64.2/32 is directly connected, Serial0/0
192.168.112.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.112.0/24 [90/21024000] via 192.168.64.2, 00:02:31, Serial0/0
D 192.168.112.2/32 [90/21024000] via 192.168.64.2, 00:02:31, Serial0/0
D 192.168.0.0/24 [90/20514560] via 192.168.64.2, 00:02:31, Serial0/0
Eastasman#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
D 192.168.72.0/24 [90/21026560] via 192.168.112.1, 00:01:35, Serial0/0
C 192.168.120.0/24 is directly connected, FastEthernet0/0
192.168.64.0/24 is variably subnetted, 2 subnets, 2 masks
D 192.168.64.0/30 [90/21024000] via 192.168.112.1, 00:01:35, Serial0/0
D 192.168.64.1/32 [90/21024000] via 192.168.112.1, 00:01:35, Serial0/0
192.168.112.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.112.0/24 is directly connected, Serial0/0
C 192.168.112.1/32 is directly connected, Serial0/0
D 192.168.0.0/24 [90/20514560] via 192.168.112.1, 00:01:35, Serial0/0
Issue an extended ping command to test end-to-end connectivity:
Eastasman#ping
Protocol [ip]: ip
Target IP address: 192.168.72.1
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: 192.168.120.1
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.72.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 72/77/96 ms
8-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
Step 7
Document your work.
.
1-8 Semester 8 Internetwork Troubleshooting v1.0 - Lab 12.2.1.1 Copyright 2001, Cisco Systems, Inc.
Lab 12.2.1.1 EIGRP Troubleshooting
F0/0 192.168.0.1/24
S0/1. | begin router eigrp
router eigrp 123
network 192.168.0.0
network 192.168.64.0 0.0.0.3
network 192.168.112.0
no auto-summary
eigrp log-neighbor-changes