On Tue, 24 Jan 2023 18:41:56 +0000 (GMT) Tim Woodall <debianu...@woodall.me.uk> wrote:
> On Mon, 23 Jan 2023, Celejar wrote: > > > Thank you - the plot thickens. I tried radvdump, and I was indeed > > receiving IPv6 advertisements. I inspected my router (an OpenWrt box) > > more carefully, and lo and behold, the router *thinks* that it has IPv6 > > connectivity: it reports that it has configured its WAN interface via > > DHCPv6, that it has an IPv6 prefix delegation (a /56), and that it has > > accordingly handed out an IPv6 address via DHCPv6 to my Debian system > > (which indeed shows having its network interface configured with that > > address). The problem is that IPv6 is not actually working at all: > > ping6 to IPv6 hosts, even from the router itself, get no response, and > > traceroute to IPv6 hosts show replies from only the first two hops, and > > just asterisks afterward. > > > > My ISP is notoriously cagey about the details of its (slow and > > incremental) IPv6 rollout. I suppose I can try customer service, but in > > the meantime, I just don't know whether I have a misconfiguration on the > > router, or whether the ISP is not actually providing working IPv6. > > > > Does ping/traceroute work in ipv4? Yes - pinging the same hosts that don't work using IPv6 works with ping -4, and traceroute works with IPv4 addresses as well (I get some asterisks, but many / most of the hops, including the destinations, respond). > It's depressingly common to find people who block icmp for 'security > reasons'. While you can mostly get away with that in ipv4, ipv6 breaks > catastrophically without at least some working icmp. > > Also try tcptraceroute - although if some router is configured to drop > all icmp then I don't think ipv6 can work at all tcptraceroute work fine. tcptraceroute6 gives the same problem as regular traceroute6 - all asterisks after the first couple of hops. -- Celejar
