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 * * *
3 222.42.254.130 (222.42.254.130) 7.980 ms 10.785 ms 4.920 ms
4 222.42.254.129 (222.42.254.129) 4.363 ms 8.141 ms 5.849 ms
5 bogon (10.2.1.1) 7.957 ms 7.787 ms 8.321 ms
6 61.237.121.97 (61.237.121.97) 25.341 ms 24.895 ms 28.725 ms
7 61.237.123.66 (61.237.123.66) 23.738 ms 24.172 ms 23.916 ms
8 221.4.120.173 (221.4.120.173) 23.096 ms 24.539 ms 20.827 ms
9 221.4.6.61 (221.4.6.61) 58.516 ms 60.035 ms 63.200 ms
10 120.80.0.73 (120.80.0.73) 60.991 ms 59.520 ms 59.853 ms
11 219.158.19.69 (219.158.19.69) 59.771 ms 59.192 ms 59.072 ms
12 219.158.22.249 (219.158.22.249) 89.185 ms 87.928 ms 89.582 ms
13 219.158.22.158 (219.158.22.158) 102.195 ms 103.409 ms 106.153 ms
14 219.158.35.114 (219.158.35.114) 218.816 ms 224.845 ms 218.470 ms
15 203.208.62.15 (203.208.62.15) 212.560 ms 208.640 ms *
16 chrome.google.com (203.208.46.1) 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 below:
- Why did I get some hops while I use ICMP?
- How can I get the first two hops?
I have searched for that, but I got nothing useless. I connect to the Internet through a route without any firewall. Thank you for your help.