Ping and tracert example

As shown in Figure 4, Device A failed to Telnet to Device C. Determine whether Device A and Device C can reach each other. If they cannot reach each other, locate the failed nodes in the network.

1. Use the ping command to test connectivity between Device A and Device C.

   <DeviceA> ping 1.1.2.2
     PING 1.1.2.2: 56  data bytes, press CTRL_C to break
       Request time out
       Request time out
       Request time out
       Request time out
       Request time out
   
     --- 1.1.2.2 ping statistics ---
       5 packet(s) transmitted
       0 packet(s) received
   100.00% packet loss
   

2. The output shows that Device A and Device C cannot reach each other.

3. Use the tracert command to identify failed nodes:

4. # Enable sending of ICMP timeout packets on Device B.

   <DeviceB> system-view
   [DeviceB] ip ttl-expires enable
   

5. # Enable sending of ICMP destination unreachable packets on Device C.

   <DeviceC> system-view
   [DeviceC] ip unreachables enable
   

6. # Execute the tracert command on Device A.

   <DeviceA> tracert 1.1.2.2
    traceroute to 1.1.2.2(1.1.2.2) 30 hops max,40 bytes packet, press CTRL_C to break
    1  1.1.1.2 14 ms 10 ms 20 ms
    2  * * *
    3  * * *
    4  * * *
    5
   <DeviceA>
   

   The output shows that Device A and Device C cannot reach other, that Device A and Device B can reach each other, and that an error occurred on the connection between Device B and Device C.

7. Use the debugging ip icmp command on Device A and Device C to verify that they can send and receive the specific ICMP packets, or use the display ip routing-table command to verify the availability of active routes between Device A and Device C.