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.
