Tracert example

Network requirements

As shown in Figure 3, Device A failed to Telnet to Device C.

Test the network connectivity between Device A and Device C. If they cannot reach each other, locate the failed nodes in the network.

Figure 3: Network diagram

Configuration procedure

  1. Configure the IP addresses for devices as shown in Figure 3.

  2. Configure a static route on Device A.

    <DeviceA> system-view
    [DeviceA] ip route-static 0.0.0.0 0.0.0.0 1.1.1.2
    [DeviceA] quit
    
  3. Use the ping command to test connectivity between Device A and Device C.

    <DeviceA> ping 1.1.2.2
    Ping 1.1.2.2(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
    
    --- Ping statistics for 1.1.2.2 ---
    5 packet(s) transmitted,0 packet(s) received,100.0% packet loss
    

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

  4. Use the tracert command to identify failed nodes:

    # Enable sending of ICMP timeout packets on Device B.

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

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

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

    # 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 at most,40 bytes each packet, press CTRL_C to break
     1  1.1.1.2 (1.1.1.2) 1 ms 2 ms 1 ms
     2  * * *
     3  * * *
     4  * * *
     5
    <DeviceA>
    

    The output shows that Device A can reach Device B but cannot reach Device C. An error has occurred on the connection between Device B and Device C.

  5. To identify the cause of the problem, execute the following commands on Device A and Device C:

    • Execute the debugging ip icmp command and verify that Device A and Device C can send and receive the correct ICMP packets.

    • Execute the display ip routing-table command to verify that Device A and Device C have a route to each other.