Ping 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.
• 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.

Network Topology

Figure 1-1 ping application networking

Configuration Steps

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

Step 2: Use the ping command to view whether the route between Device1 and Device3 is reachable.

#View whether Device1 can ping the IP address 2.0.0.2 of Device3.

Device1#ping 2.0.0.2   
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 2.0.0.2 , timeout is 2 seconds: 
..... 
Success rate is 0% (0/5). 

#View whether Device1 can ping the IPv6 address 2001:2::2 of Device3.

Device1#ping 2001:2::2 
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 2001:2::2 , timeout is 2 seconds: 
..... 
Success rate is 0% (0/5).

Step 3: Use the ping command to view whether the route between Device1 and Device2 is reachable.

#View whether Device1 can ping the IP address 1.0.0.2 of Device2.

Device1#ping 1.0.0.2 	 
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 1.0.0.2 , timeout is 2 seconds: 
!!!!! 
Success rate is 100% (5/5). Round-trip min/avg/max = 0/0/0 ms. 

#View whether Device1 can ping the IPv6 address 2001:1::2 of Device2.

Device1#ping 2001:1::2 
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 2001:1::2 , timeout is 2 seconds: 
!!!!! 
Success rate is 100% (5/5). Round-trip min/avg/max = 0/0/0 ms. 

Step 4: Use the ping command to view whether the route between Device2 and Device3 is reachable.

#View whether Device2 can ping IP address 2.0.0.2 of Device3.

Device2#ping 2.0.0.2 
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 2.0.0.2 , timeout is 2 seconds: 
!!!!! 
Success rate is 100% (5/5). Round-trip min/avg/max = 0/0/0 ms. 

#View whether Device2 can ping the IPv6 address 2001:2::2 of Device3.

Device2#ping 2001:2::2 
 
Press key (ctrl + shift + 6) interrupt it. 
Sending 5, 76-byte ICMP Echos to 2001:2::2 , timeout is 2 seconds: 
!!!!! 
Success rate is 100% (5/5). Round-trip min/avg/max = 0/176/883 ms. 

From the above result, we can see that Device1 and Device2 can communicate with each other, Device2 and Device3 can communicate with each other, and the problem appears between Device1 and Device3. Later, we can check the route configuration, or use the debug ip icmp and debug ipv6 icmp commands to view whether the contents of the ICMP packet and ICMPv6 packet are correct. We also can use traceroute described in the next section to confirm the faulty network node.