Traceroute Application

Network Requirement

• Device1 fails to log into Device3 by telnetting IP address and we need to confirm whether the IP route between Device1 and Device3 is reachable. If the route is unreachable, we need to confirm the faulty network node.
• Device1 fails to log into Device3 by telnetting IPv6 address and we need to confirm whether the IPv6 route between Device1 and Device3 is reachable. If the route is unreachable, we need to confirm the faulty network node.

Network Topology

Figure 1-2 Traceroute application networking

Configuration Steps

Step 1: Configure the IP address and IPv6 global unicast address of the interface. (Omitted)

Step 2: Use the traceroute command to confirm the fault point between Device1 and Device3.

#Use the traceroute command to confirm the IPv4 fault point between Device1 and Device3.

Device1#traceroute 2.0.0.2 Type escape sequence to abort. 
Tracing the route to 2.0.0.2 , min ttl = 1, max ttl = 30 . 
 
  1 1.0.0.2 0 ms 0 ms   0 ms 
  2 * *      * 
  3 * *      * 
  4 * *      * 
  5 * *      * 
  6   

#Use the traceroute command to confirm the IPv6 fault point between Device1 and Device3.

Device1#traceroute 2001:2::2 
 
Type escape sequence to abort. 
Tracing the route to 2001:2::2 , min ttl = 1, max ttl = 30 . 
 
   1 2001:1::2 0 ms 0 ms 0 ms     
   2 *   *   *     
   3 *   *   *     
   4 *   *   *     
   5 *   *   *     
   6  

From the above result, the traceroute packet sent by Device1 can reach Device2. The traceroute packet from Device2 cannot reach Device3. Later, we need to check the route configuration between Device2 and Device3 and line, or use the debug ip icmp and debug ipv6 icmp command to view whether the contents of the ICMP packet and ICMPv6 packet are correct. We also can use ping described in the last section to detect the connection between Device2 and Device3.