kasperd on Nostr: That hostname resolves to `2a05:87c6:1:1cc8::1` for me. I confirmed that the IP ...

That hostname resolves to `2a05:87c6:1:1cc8::1` for me. I confirmed that the IP address is reachable from most networks I tried but it is not reachable from Mythic Beasts (npub1wy5…64vc) or Andrews & Arnold Ltd (AAISP) (npub1sv0…rq9x)

The problem seems to affect both ssh and ping. With both protocols I get an ICMPv6 error message back:
```
ICMP6, destination unreachable, unreachable address 2a05:87c6:1:1cc8::1, length 88
```

The origin of the ICMPv6 error message is 2001:8b0:0:53::109 or 2a00:1098:2::7 depending on which provider I connect from.

Here is an example traceroute output:
```
root@nat64-london:~# traceroute -n -I 2a05:87c6:1:1cc8::1
traceroute to 2a05:87c6:1:1cc8::1 (2a05:87c6:1:1cc8::1), 30 hops max, 80 byte packets
1 2a00:1098:1::2d 0.284 ms 0.231 ms 0.217 ms
2 2a00:1098:2:ffff::9c 0.401 ms 0.387 ms 0.375 ms
3 2a00:1098:2:1::1c:1 0.437 ms 0.417 ms 0.453 ms
4 2a00:1098:2::7 0.323 ms 0.376 ms 0.365 ms
5 2a00:1098:2::7 3055.197 ms !H 3055.184 ms !H 3055.165 ms !H
root@nat64-london:~#
```

The last hop limit exceeded message came from the same IP as the unreachable address. The later error message was delayed by 3 seconds.

In my experience the 3 second delay is most often caused by a neighbor discovery timeout. That indicates that 2a00:1098:2::7 and 2001:8b0:0:53::109 have a route forward towards the destination, but the next hop is not responding to neighbor solicitation messages.