CCENT Question 104: Troubleshooting Ping Failure

Today’s question turns the #CCENT discussion around, from “what happens when it works” to “what might cause it to not work”. Like the previous three questions, it mixes layers 2 and 3, this time requiring some troubleshooting analysis. The question uses the same figure as the last few questions, with the idea that one single thing is broken in the network. What can you rule out, and what can you rule in?

The Scenario: Question 104

In this scenario, PC4 acts as a web server, with users sitting at PC1 and PC2. The figure shows IPv4 addressing information, and pseudo-MAC addresses (eg, PC1-MAC for PC1’s MAC address).  PC1 and PC2 will ping PC4’s IP address.

Figure 103: Network Used for Question 103

Question

An engineer has the documentation shown in the figure. All switch interfaces sit in VLAN 1. The user at PC1 claims that when they issue a ping 10.1.2.4 command, it works. However, when the user at PC2 issues the same command, it fails, (shows multiple periods.) Which of the following answers lists a possible cause of the current conditions? Note that multiple correct answers may exist. Also, note that the information in the figure may be incorrect (as noted in an answer).

a)     Misconfiguration of R1’s G0/0 IP address/mask to 10.1.1.254/25

b)     Port Security on SW4’s G0/2 interface

c)     A speed mismatch on one Ethernet link

d)     R1’s G0/0 interface being configured with the shutdown command