On 05/22/2017 02:13 PM, Alarig Le Lay wrote: > You can try to ping6 the IPv6 multicast address for all the routers on > the link: > > 14:07 alarig@mew ~ % ping6 -c1 ff02::2%vtnet0 > PING6(56=40+8+8 bytes) fe80::a800:ff:fe93:83a3%vtnet0 --> ff02::2%vtnet0 > 16 bytes from fe80::209%vtnet0, icmp_seq=0 hlim=64 time=0.237 ms > > --- ff02::2%vtnet0 ping6 statistics --- > 1 packets transmitted, 1 packets received, 0.0% packet loss > round-trip min/avg/max/std-dev = 0.237/0.237/0.237/0.000 ms
In this use case, you make the assumption that my gateway is actually the first one to respond, this is why you select only the first answer using -c1. But as you can see below, if I remove that argument, several routers are answering to me (seems sensible to me), how can I be sure my gateway is actually the first device that answers? PING6(56=40+8+8 bytes) fe80::ff:fec2:e61d%vtnet0 --> ff02::2%vtnet0 16 bytes from fe80::268a:7ff:fe91:e970%vtnet0, icmp_seq=0 hlim=64 time=0.292 ms 16 bytes from fe80::268a:7ff:fe91:ea98%vtnet0, icmp_seq=0 hlim=64 time=0.355 ms(DUP!) 16 bytes from fe80::2ff:ffff:feff:fffd%vtnet0, icmp_seq=0 hlim=64 time=2.970 ms(DUP!) 16 bytes from fe80::2ff:ffff:feff:fffe%vtnet0, icmp_seq=0 hlim=64 time=5.964 ms(DUP!) 16 bytes from fe80::268a:7ff:fe91:e970%vtnet0, icmp_seq=1 hlim=64 time=0.314 ms 16 bytes from fe80::268a:7ff:fe91:ea98%vtnet0, icmp_seq=1 hlim=64 time=0.389 ms(DUP!) 16 bytes from fe80::2ff:ffff:feff:fffd%vtnet0, icmp_seq=1 hlim=64 time=3.222 ms(DUP!) 16 bytes from fe80::2ff:ffff:feff:fffe%vtnet0, icmp_seq=1 hlim=64 time=6.382 ms(DUP!) How can I understand the "DUP!" statement here? I assume these are due because we are using multicast here end the ICMP reply are echoes to each others? Right? > > But, it’s possible that you don’t get any reply if they do some nasty > things on their network (as Hetzner does). In that case, you’re stuck on > the /56 setup. > As you can see, it seems there is no restriction / too nasty things at OVH, as I have got replies, at least :) Regards, -- William Gathoye <will...@gathoye.be>
signature.asc
Description: OpenPGP digital signature
