Cannot ping, but can traceroute? Try extended ping!

Sometimes, after we configure the IP address for our routers, check the cable and make sure everything is right, we expect that we can ping everything!

However, weird things happen. When I checked the show ip route, I knew that RIP was working and connected all routers. The Corp router with IP address 171.16.10.1 was connected via Lab_A router (IP address 192.168.20.1).

I pinged Corp from Lab_B, here is the result:

Lab_B#ping 171.16.10.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 171.16.10.1, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)

Then I tried traceroute:

Lab_B#traceroute 171.16.10.1

Type escape sequence to abort.
Tracing the route to 171.16.10.1

1 192.168.20.1 684 msec * 2580 msec
2 171.16.10.1 1364 msec 1612 msec 1364 msec

Almost frustrated, then I tried the extended ping:

Lab_B#ping
Protocol [ip]:
Target IP address: 171.16.10.1
Repeat count [5]: 10
Datagram size [100]:
Timeout in seconds [2]: 4
Extended commands [n]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 171.16.10.1, timeout is 4 seconds:
!!!!!!.!!.
Success rate is 80 percent (8/10), round-trip min/avg/max = 2904/2995/3596 ms

Interesting, huh? Look closely at the time marked in red. Sometimes, the time needed to reach the destination is more than 2 seconds, which is the default for ping. That’s why when I changed the timeout to 4 seconds in extended ping, I got the result.

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