CCNA Activities - Interpreting Ping and Traceroute Output

Topology Diagram

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Objectives

• Distinguish the difference between successful and unsuccessful ping attempts.
• Distinguish the difference between successful and unsuccessful traceroute attempts.

Background / Preparation
In this activity, you will test end-to-end connectivity using ping and traceroute. At the end of this activity, you will be able to distinguish the difference between successful and unsuccessful ping and traceroute attempts.
Note: Before beginning this activity, make sure that the network is converged. To converge the network quickly, switch between Simulation mode and Real-time mode until all the link lights turn green.

Step 1: Test connectivity using ping from a host computer and a router.
a. Click N-Host, click the Desktop tab, and then click Command Prompt. From the Command Prompt window, ping the Cisco server at www.cisco.com.
Packet Tracer PC Command Line 1.0
PC>ping www.cisco.com
Pinging 64.100.1.185 with 32 bytes of data:

Request timed out.
Reply from 64.100.1.185: bytes=32 time=185ms TTL=123
Reply from 64.100.1.185: bytes=32 time=281ms TTL=123
Reply from 64.100.1.185: bytes=32 time=287ms TTL=123

Ping statistics for 64.100.1.185:
    Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
Approximate round trip times in milli-seconds:
    Minimum = 185ms, Maximum = 287ms, Average = 251ms

PC>

b. From the output, you can see that N-Host was able to obtain an IP address for the Cisco server. The IP address was obtained using (DNS). Also notice that the first ping failed. This failure is most likely due to lack of ARP convergence between the source and destination. If you repeat the ping, you will notice that all pings succeed.

c. From the Command Prompt window on N-Host, ping E-Host at 192.168.4.10. The pings fail. If you do not want to wait for all four unsuccessful ping attempts, press Ctrl+C to abort the command, as shown below.

PC>ping 192.168.4.10
Pinging 192.168.4.10 with 32 bytes of data:
Request timed out.
Request timed out.

Ping statistics for 192.168.4.10:
Packets: Sent = 3, Received = 0, Lost = 3 (100% loss),
Control-C
^C
PC>

d. Click the N-Branch router, and then click the CLI tab. Press Enter to get the router prompt. From the router prompt, pings the Cisco server at www.cisco.com.

N-Branch>ping www.cisco.com
Translating "www.cisco.com"...domain server (64.100.1.242)
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 64.100.1.185, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 210/211/213 ms

N-Branch>

e. As you can see, the ping output on a router is different from a PC host. Notice that the N-Branch router resolved the domain name to the same IP address that N-Host used to send its pings. Also notice that the first ping fails, which is indicated by a period (.), and that the next four pings succeed, as shown with an exclamation point (!).

f. From the CLI tab on N-Branch, ping E-Host at 192.168.4.10. Again, the pings fail. To not wait for all the failures,
press Ctrl+C.
N-Branch>ping 192.168.4.10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.4.10, timeout is 2 seconds: ...
Success rate is 0 percent (0/4)

N-Branch>

Step 2: Test connectivity using traceroute from a host computer and a router.

a. Click N-Host, click the Desktop tab, and then click Command Prompt. From the Command Prompt window, trace the route to the Cisco server at www.cisco.com.

PC>tracert www.cisco.com

Tracing route to 64.100.1.185 over a maximum of 30 hops:

  1   92 ms     77 ms     86 ms     192.168.1.1
  2   91 ms     164 ms    84 ms     64.100.1.101
  3   135 ms    168 ms    151 ms    64.100.1.6
  4   185 ms    261 ms    161 ms    64.100.1.34
  5   257 ms    280 ms    224 ms    64.100.1.62
  6   310 ms    375 ms    298 ms    64.100.1.185

Trace complete.

PC>

b. The above output shows that you can successfully trace a route all the way to the Cisco server at 64.100.1.185. Each hop in the path is a router responding three times to trace messages from N-Host. The trace continues until the destination for the trace (64.100.1.185) responds three times.

c. From the Command Prompt window on N-Host, trace a route to E-Host at 192.168.4.10. The trace fails, but notice that the tracert command traces up to 30 hops. If you do not want to wait for all 30 attempts to time out, press Ctrl+C.

PC>tracert 192.168.4.10

Tracing route to 192.168.4.10 over a maximum of 30 hops:

  1   103 ms    45 ms     91 ms     192.168.1.1
  2   56 ms     110 ms    125 ms    64.100.1.101
  3   174 ms    195 ms    134 ms    64.100.1.6
  4   246 ms    183 ms    179 ms    64.100.1.34
  5   217 ms    285 ms    226 ms    64.100.1.62
  6   246 ms    276 ms    245 ms    64.100.1.154
  7   *         *         *         Request timed out.
  8   *         *         *         Request timed out.
  9   *         *         *         Request timed out.
  10  

Control-C
^C
PC>

The tracert command can be helpful in finding the potential source of a problem. The last device to respond was 64.100.1.154, so you would start troubleshooting by determining which device is configured with the IP address 64.100.1.154. The source of the problem might not be that device, but the trace has given you a starting point, whereas a ping simply tells you that the destination is either reachable or unreachable.

d. Click the N-Branch router, and then click the CLI tab. Press Enter to get the router prompt. From the router prompt, trace the route to the Cisco server at www.cisco.com.

N-Branch>traceroute www.cisco.com
Translating "www.cisco.com"...domain server (64.100.1.242)
Type escape sequence to abort.
Tracing the route to 64.100.1.185

  1   64.100.1.101    60 msec   32 msec   59 msec  
  2   64.100.1.6      98 msec   65 msec   65 msec  
  3   64.100.1.34     138 msec  147 msec  147 msec 
  4   64.100.1.62     189 msec  148 msec  145 msec 
  5   64.100.1.185    219 msec  229 msec  293 msec 
N-Branch>

As you can see, traceroute output on a router is very similar to the output on a PC host. The only difference is that on a PC host, the IP address is listed after the three millisecond outputs.

e. From the CLI tab on N-Branch, trace the route to E-Host at 192.168.4.10. The trace fails at the same IP address as it failed when tracing from N-Host. Again, you can use Ctrl+C to abort the command.

N-Branch>traceroute 192.168.4.10
Type escape sequence to abort.
Tracing the route to 192.168.4.10

  1   64.100.1.101    41 msec   19 msec   32 msec  
  2   64.100.1.6      33 msec   92 msec   117 msec 
  3   64.100.1.34     98 msec   102 msec  102 msec 
  4   64.100.1.62     166 msec  172 msec  156 msec 
  5   64.100.1.154    157 msec  223 msec  240 msec 
  6   *     *     *    
  7   *     *     *    
  8   *     *     *    
  9  
N-Branch>
Step 3: Practice the ping and trace route commands.

Throughout this course, you will often use ping and traceroute to test connectivity and troubleshoot problems. To practice these commands, ping and trace from W-Host and S-Host to any other destination in the network. You can also ping and trace from N-Branch to other locations.