Take the 2-minute tour ×  I have some questions about why
traceroute doesn't works in some condition. Though I understand
how it works, I can't figure out some questions. Like,
$traceroute www.google.com  1  * * *  2  * * *  There are '*'.
When I use ICMP stead for UDP, I got those below:  $traceroute
www.google.com -I  1  * * *  2  * * *  3 (  7.980 ms  10.785 ms
4.920 ms  4 (  4.363 ms  8.141 ms  5.849 ms  5  bogon (  7.957
ms  7.787 ms  8.321 ms  6 (  25.341 ms  24.895 ms  28.725 ms  7
(  23.738 ms  24.172 ms  23.916 ms  8 (  23.096 ms  24.539 ms
20.827 ms  9 (  58.516 ms  60.035 ms  63.200 ms 10 (  60.991 ms
59.520 ms  59.853 ms 11 (  59.771 ms  59.192 ms  59.072 ms 12 (
89.185 ms  87.928 ms  89.582 ms 13 (  102.195 ms  103.409 ms
106.153 ms 14 (  218.816 ms  224.845 ms  218.470 ms 15 (
212.560 ms  208.640 ms * 16  chrome.google.com (  210.655 ms *
216.369 ms  I wonder why the first and second hop is still
unknown. I have tried to set icmp rate with -z 500, but it's
useless. So my questions are be