I'm trying to understand one specific behaviour of the command traceroute, when I run the command:
traceroute facebook.com
I realised that sometimes each probe report different host for the same TTL:
root@b53716de78ef:/# traceroute facebook.com
traceroute to facebook.com (31.13.83.36), 30 hops max, 60 byte packets
1 172.17.0.1 (172.17.0.1) 1.036 ms 0.975 ms 0.942 ms
2 10.13.254.254 (10.13.254.254) 2.232 ms 2.650 ms 3.111 ms
3 nat.1337.ma (10.21.1.1) 3.217 ms 3.322 ms 3.434 ms
4 197.230.30.145 (197.230.30.145) 3.561 ms 4.086 ms 4.213 ms
5 10.43.88.105 (10.43.88.105) 4.326 ms 4.674 ms 5.303 ms
6 * * *
7 * * *
8 * * *
9 * * *
10 10.43.82.106 (10.43.82.106) 19.200 ms 20.204 ms 19.251 ms
11 10.43.250.213 (10.43.250.213) 37.221 ms 33.647 ms 33.827 ms
12 ae76.pr04.mad1.tfbnw.net (157.240.83.28) 63.274 ms ae20.pr03.mad1.tfbnw.net (157.240.66.56) 64.214 ms ae76.pr04.mad1.tfbnw.net (157.240.83.28) 55.594 ms
13 po204.asw02.mad1.tfbnw.net (129.134.105.68) 40.668 ms po203.asw02.mad2.tfbnw.net (129.134.35.154) 36.076 ms po203.asw02.mad1.tfbnw.net (129.134.99.134) 40.271 ms
14 psw03.mad1.tfbnw.net (173.252.66.198) 35.236 ms psw01.mad1.tfbnw.net (173.252.66.199) 35.571 ms psw02.mad1.tfbnw.net (173.252.66.197) 39.186 ms
15 157.240.38.197 (157.240.38.197) 39.795 ms 157.240.39.7 (157.240.39.7) 40.066 ms 157.240.38.81 (157.240.38.81) 38.868 ms
16 edge-star-mini-shv-01-mad1.facebook.com (31.13.83.36) 40.409 ms 39.675 ms 39.459 ms
But when I use the ICMP protocol with the option -I, it looks like it always reports the same host:
root@b53716de78ef:/# traceroute -I facebook.com
traceroute to facebook.com (31.13.83.36), 30 hops max, 60 byte packets
1 172.17.0.1 (172.17.0.1) 0.436 ms 7.035 ms *
2 10.13.254.254 (10.13.254.254) 1.270 ms * *
3 nat.1337.ma (10.21.1.1) 1.285 ms * *
4 197.230.30.145 (197.230.30.145) 2.062 ms * *
5 10.43.88.105 (10.43.88.105) 2.350 ms * *
6 * * *
7 * * *
8 * * *
9 * * *
10 10.43.82.106 (10.43.82.106) 18.611 ms 18.632 ms 18.694 ms
11 10.43.250.213 (10.43.250.213) 44.350 ms 34.612 ms 34.356 ms
12 ae20.pr03.mad1.tfbnw.net (157.240.66.56) 36.722 ms 36.317 ms 35.640 ms
13 po203.asw02.mad1.tfbnw.net (129.134.99.134) 39.715 ms 39.599 ms 39.615 ms
14 po232.psw04.mad1.tfbnw.net (129.134.67.41) 35.467 ms 34.495 ms 34.320 ms
15 157.240.39.9 (157.240.39.9) 40.631 ms 39.895 ms 39.959 ms
16 edge-star-mini-shv-01-mad1.facebook.com (31.13.83.36) 40.106 ms 40.599 ms *
I wonder if someone would explain in details what could be the cause of this behaviour.
PS: I must mention that I'm coding my own version of traceroute in C and that is why it is not so clear why I always get the same host too.
