I can't reach my machine through IPV6 in the same LAN (but I CAN do it from an outside network)

First of all, let me say that I googled the hell out before posting this issue here. And it seems like very little people has this kind of issue. Usually, people have issues like not being able to access external ipv6 sites, or not being able to reach their device from the internet.

My issue is like the oposite of that. I have configured a OMV6 Raspberry Pi on my parents home. I can reach the device normally from my home (over the internet). I can SSH in the RPi and ping6 ipv6 sites normally. Everything seems to be ok on this matter.

However, when I'm in my parents home and try to access the RPi, that is, through the local network the RPi is hooked on, I just can't reach it .

Any insights will be appreciated, thank you.

Quote from gderf

Try using the multicast IPv6 address of the OMV box (They start with FF02::) when connecting from the LAN.

I will try that as soon as I can (when I'm there again or when my father is available on AnyDesk ), but meanwhile, I might found something relevant with regard to your suggestion:

I have my own OMV6 machine at my home, wich I can access from both LAN and internet using ipv6. This is the result of cat /etc/hosts:

# This file is auto-generated by openmediavault (https://www.openmediavault.org)
# WARNING: Do not edit this file, your changes will get lost.
127.0.0.1 localhost.localdomain localhost
127.0.1.1 omv6.local omv6
# The following lines are desirable for IPv6 capable hosts.
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

If I type ping ff02::1  (all nodes), then it pings a lot of hosts, including my OMV6 machine:

PING ff02::1(ff02::1) 56 data bytes
64 bytes from fe80::bbbb:rrrr:mc50:5180%enp2s0: icmp_seq=1 ttl=64 time=0.055 ms
64 bytes from fe80::cccc:2776:qqqq:983%enp2s0: icmp_seq=1 ttl=64 time=0.265 ms
64 bytes from fe80::1%enp2s0: icmp_seq=1 ttl=64 time=0.634 ms
64 bytes from fe80::xxxx:yyyy:aaaa:1118%enp2s0: icmp_seq=1 ttl=64 time=1.16 ms
64 bytes from fe80::xxxx:yyyy:aaaa:16cc%enp2s0: icmp_seq=1 ttl=64 time=1.18 ms
64 bytes from fe80::xxxx:yyyy:aaaa:1848%enp2s0: icmp_seq=1 ttl=64 time=6.43 ms
64 bytes from fe80::xxxx:xxxx:106b%enp2s0: icmp_seq=1 ttl=64 time=106 ms
^C
--- ff02::1 ping statistics ---
1 packets transmitted, 1 received, +6 duplicates, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.055/16.516/105.903/36.548 ms

(addresses edited for security purposes)

If I try the same thing on the Raspberry Pi located at my parents' home, the ping is unsuccessfull - I get no packets received from anywhere:

PING ff02::1(ff02::1) 56 data bytes
^C
--- ff02::1 ping statistics ---
12 packets transmitted, 0 received, 100% packet loss, time 11445ms

By the way, this is the content of /etc/hosts on the RPi:

127.0.0.1       localhost
::1             localhost ip6-localhost ip6-loopback
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters

127.0.1.1               raspberrypi

I hope this is useful.

Quote from chente

Install this on your dad's raspeberry and you won't need AnyDesk.

[How-To] Install Wireguard (VPN) in docker, server mode

Have you found a really good guide about how to setup Wireguard on docker using IPV6? Because it is a nightmare....

Anyway, I'm trying something different than a VPN solution, because I want my domain to point to a single IPV6 address, that I can use from both inside the LAN and over the internet.

As I said, I'm already doing that with the x86 OMV6 machine I have in my home. I just can't do it with the Raspberry Pi.