Reachability test fails despite router configuration

Hello together,

maybe someone can help me:

The reachability test of the next box fails despite having configured the router (a fritzBox) (hopefully) correctly:
port forwarding on ports 80 and 443 is active, the domain ( is whitelisted for the DNS-Rebind protection, IA_PD and IA_NA is enabled.
Even if it doesn’t matter: the isp is providing a full dual stack IPv4/IPv6 and the router is configured to default to IPv6.

The dyndns is also working correctly: the Box is reachable from external devices via the designated URL - as well as by the globla IPv4 adress of the router and the IPv6 adress of the NextBox.

What am I missing? Thanks a lot in advance.

(As I see it, this problem doesn’t cause any usability problems yet, but it’s still bothering me :sweat_smile:)

That’s a good question, good to see that there is no actual issue, still the reachability test is quite error prone. But haven’t observed this behavior yet. My guess would be it has something to do with the forwarding (for ipv4), it might be that the NextBox tries to use IPv4, thus ends up on the router, with the router blocking the traffic instead of forwarding. Did you set up forwarding for IPv4 and IPv6 ?

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Hello daringer,

yes, I have both IPv4 and IPv6 port-forwarding active.
Am I right in assuming that the reachability test is logged in journald.nextbox-deamon.log? Because there it shows that the /dyndns/test/http function returns an 200 status code (“ok”):

Jul 26 15:23:46 nextbox nextbox-daemon[660]: - - [26/Jul/2021 15:23:46] “GET /dyndns/test/resolve/ipv6 HTTP/1.0” 200 -
Jul 26 15:23:49 nextbox nextbox-daemon[660]: - - [26/Jul/2021 15:23:49] “GET /dyndns/test/resolve/ipv4 HTTP/1.0” 200 -
Jul 26 15:23:49 nextbox nextbox-daemon[660]: - - [26/Jul/2021 15:23:49] “GET /dyndns/test/http HTTP/1.0” 200 -

But, as i said: as for now, everything else seems to work as intended (exept the CODE-server, which was to be expected).

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