One drop while tracing - icmp unreachable & traceroute
Have you ever notice the * * while you are tracing some destination ? Cochran#traceroute 192.168.16.1 probe 4 Type escape sequence to abort. Tracing the route to 192.168.16.1 1 172.20.15.5 4 msec 4 msec 0 msec 0 msec 2 172.20.15.2 4 msec * 0 msec * Cochran# When you ping no drops at all Cochran#ping 192.168.16.1 repeat 4 Type escape sequence to abort. Sending 4, 100-byte ICMP Echos to 192.168.16.1, timeout is 2 seconds: !!!! Success rate is 100 percent (4/4), round-trip min/avg/max = 4/5/8 ms This behaviour due to ICMP unreachable rate limit configuration , only the last hop needs to generate icmp-unreachble others normally return the reply via ttl expired ( remember the way traceroute works ) Lindbergh#show ip int brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 unassigned YES NVRAM administratively down down Serial0/0 172.20.15.2 YES NVRAM up up ...