2.3.2.3 Packet Tracer - Troubleshooting Static Routes Instructions Answers

Packet Tracer - Troubleshooting Static Routes

(Instructor Version)

Instructor Note: Red font color or Gray highlights indicate text that appears in the instructor copy only.

Topology

Addressing Table

Device	Interface	IPv4 Address	Subnet Mask	Default Gateway
R1	G0/0	172.31.1.1	255.255.255.128	N/A
R1	S0/0/0	172.31.1.194	255.255.255.252	N/A
R2	G0/0	172.31.0.1	255.255.255.0	N/A
	S0/0/0	172.31.1.193	255.255.255.252	N/A
	S0/0/1	172.31.1.197	255.255.255.252	N/A
R3	G0/0	172.31.1.129	255.255.255.192	N/A
R3	S0/0/1	172.31.1.198	255.255.255.252	N/A
PC1	NIC	172.31.1.126	255.255.255.128	172.31.1.1
PC2	NIC	172.31.0.254	255.255.255.0	172.31.0.1
Server	NIC	172.31.1.190	255.255.255.192	172.31.1.129

Objectives

Part 1: Locate the Problem
Part 2: Determine the Solution
Part 3: Implement the Solution
Part 4: Verify That the Issue Is Resolved

Background

In this activity, the user of PC1 reports that they cannot access resources on the server. Locate the problem, decide on an appropriate solution and resolve the issue.

Part 1: Locate the Problem

PC1 cannot access files on the server. Locate the problem using the appropriate show commands on all routers and any troubleshooting commands on the PCs that you have learned from previous chapters.

What are some of the troubleshooting commands on routers and PCs that can be used to identify the source of the problem?
show ip route, show running-config, traceroute, tracert, and ping

R1# show ip route 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP

     172.31.0.0/16 is variably subnetted, 7 subnets, 5 masks
S       172.31.0.0/24 is directly connected, Serial0/0/0
C       172.31.1.0/25 is directly connected, GigabitEthernet0/0
L       172.31.1.1/32 is directly connected, GigabitEthernet0/0
S       172.31.1.128/26 is directly connected, Serial0/0/0
C       172.31.1.192/30 is directly connected, Serial0/0/0
L       172.31.1.194/32 is directly connected, Serial0/0/0
S       172.31.1.196/30 is directly connected, Serial0/0/0

R2# show ip route 
<output omitted>
S       172.31.1.0/25 [1/0] via 172.31.1.198
S       172.31.1.128/26 [1/0] via 172.31.1.194

R3# show ip route 
S       172.31.0.0/24 is directly connected, Serial0/0/1
C       172.31.1.128/26 is directly connected, GigabitEthernet0/0
L       172.31.1.129/32 is directly connected, GigabitEthernet0/0
S       172.31.1.192/30 is directly connected, Serial0/0/1
C       172.31.1.196/30 is directly connected, Serial0/0/1
L       172.31.1.198/32 is directly connected, Serial0/0/1

Part 2: Determine the Solution

After you have located the problem that is preventing PC1 from accessing files on the server, fill in the table below.

Problem	Solution
The static routes on R2 are both using the incorrect next-hop address.	Remove the static routes and replace them with the correct next-hop router address.
There is no route listed in R3 for the R1 LAN.	Add a static route on R3 to the R1 LAN.

Part 3: Implement the Solution

a. If there are any misconfigured static routes, you must remove them before the correct ones can be added to the configuration.

R2(config)# no ip route 172.31.1.0 255.255.255.128 172.31.1.198
R2(config)# no ip route 172.31.1.128 255.255.255.192 172.31.1.194
R2(config)# ip route 172.31.1.0 255.255.255.128 172.31.1.194
R2(config)# ip route 172.31.1.128 255.255.255.192 172.31.1.198

b. Add any missing static routes by configuring directly attached routes.

R3(config)# ip route 172.31.1.0 255.255.255.128 Serial0/0/1

Part 4: Verify That the Issue Is Resolved

a. Ping from PC1 to the server.

b. Open a web connection to the server. After you correctly identify and implement the correct solution to the problem, you will receive a message in the web browser when you connect to the server.

Suggested Scoring Rubric

Activity Section	Possible Points	Earned Points
Part 1: Locate the Problem	2
Part 2: Determine the Solution	8
Packet Tracer Score	90
Total Score	100

Device Configs - Final

ROUTER R2

! ==============================================================
!--- 2.3.2.3 Packet Tracer - Troubleshooting Static Routes
!--- ANSWER SCRIPT FOR ROUTER R2
!--- Usage: copy this whole file and paste it into the R2 terminal (start at the R2> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Part 3a: Remove the misconfigured static routes and add the correct ones.
! --------------------------------------------------------------

!--- Remove the R1 LAN route that wrongly points to R3 (172.31.1.198).
no ip route 172.31.1.0 255.255.255.128 172.31.1.198

!--- Remove the R3 LAN route that wrongly points to R1 (172.31.1.194).
no ip route 172.31.1.128 255.255.255.192 172.31.1.194

!--- R1 LAN 172.31.1.0/25 - correct next hop is R1 S0/0/0 (172.31.1.194).
ip route 172.31.1.0 255.255.255.128 172.31.1.194

!--- R3 LAN 172.31.1.128/26 - correct next hop is R3 S0/0/1 (172.31.1.198).
ip route 172.31.1.128 255.255.255.192 172.31.1.198

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip route static      -> S 172.31.1.0/25 via 172.31.1.194, S 172.31.1.128/26 via 172.31.1.198
!---   ping 172.31.1.1           -> R2 reaches R1 G0/0
!---   ping 172.31.1.129         -> R2 reaches R3 G0/0
!--- Note: the wrong routes must be removed with "no ip route" first;
!--- otherwise both the wrong and the correct next hop stay in the table
!--- and traffic is load-balanced across them, so pings fail intermittently.
! ==============================================================

ROUTER R3

! ==============================================================
!--- 2.3.2.3 Packet Tracer - Troubleshooting Static Routes
!--- ANSWER SCRIPT FOR ROUTER R3
!--- Usage: copy this whole file and paste it into the R3 terminal (start at the R3> prompt). Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Part 3b: Add the missing static route as a directly attached route.
! --------------------------------------------------------------

!--- R1 LAN 172.31.1.0/25 - directly attached static route out Serial0/0/1.
ip route 172.31.1.0 255.255.255.128 Serial0/0/1

end

! --------------------------------------------------------------
!--- Save the configuration to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config


! ==============================================================
!--- Verification:
!---   show ip route static          -> S 172.31.1.0/25 is directly connected, Serial0/0/1
!---   (on PC1) ping 172.31.1.190    -> PC1 reaches the Server
!---   (on PC1) Web Browser http://172.31.1.190 -> the success message appears (Part 4b)
! ==============================================================

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