nsupdate.info fails to add connectivity-test

[rnagy]

Hi

I've added my own domain fuckery.info to nsupdate.info and configured the nameservers properly however when I try to activate the domain it fails with the following error:

Failed to add/delete host connectivity-test.fuckery.live, check your DNS server configuration. This is a requirement for setting the available flag.

This is quiet strange because according to tcpdump, there are no incoming connections at all. Using nsupdate works just fine on the same domain.

[ThomasWaldmann]

Did you read / follow the site notes?

https://www.nsupdate.info/custom/site.html

[PhrozenByte]

Same issue here, the connectivity test always fails on nsupdate.info. Looks like nsuupdate.info fails to even establish a connection to perform the connectivity test.

Running nsupdate locally works just fine:

$ nsupdate -y hmac-sha512:my-key:MY_SECRET_KEY
> server 2a01:4f8:c0c:9ed7::1
> update add connectivity-test.dyn.daniel-rudolf.de 60 IN A 127.0.0.1
> send
> quit
$ dig +short @2a01:4f8:c0c:9ed7::1 connectivity-test.dyn.daniel-rudolf.de A
127.0.0.1

Removal works locally just fine, too:

$ nsupdate -y hmac-sha512:my-key:MY_SECRET_KEY
> server 2a01:4f8:c0c:9ed7::1
> update delete connectivity-test.dyn.daniel-rudolf.de IN A
> send
> quit
$ dig +short @2a01:4f8:c0c:9ed7::1 connectivity-test.dyn.daniel-rudolf.de A

I was about to switch to a new nameserver, but ended up with broken DynDNS, because I can't even restore my previously working nameserver.

[ThomasWaldmann]

@PhrozenByte i've rebooted the VM and i can ping 2a01:4f8:c0c:9ed7::1 from nsupdate.info - can you try again?

[PhrozenByte]

~~Just tried again, got no luck. As previously reported by @rnagy it seems like that nsupdate.info isn't even trying to connect to the nameserver. For an invalid key I'd see an error in BIND's logs (just tried locally with nsupdate just to be sure), but nothing is shown.~~

Okay, just got it working by luck. There's a bug in the web interface: nsupdate.info isn't actually using the entered IP address to do the connectivity test. I presume it's using the previously stored IP address instead. You can reproduce the bug as follows:

1. Create a new or edit an existing domain. Enter an invalid IP address as nameserver (e.g. 10.0.0.1), leave "Available" unchecked and hit "Update".
2. Edit the same domain again and enter the right IP address (e.g. 2a01:4f8:c0c:9ed7::1).
   1. Check "Available" and hit "Update". nsupdate.info will refuse the nameserver due to a failing connectivity test. This shouldn't happen, as the newly entered IP address is indeed working.
   2. Uncheck "Available" and hit "Update" (i.e. just store the right IP address).
3. Edit the same domain once again and just check "Available". Hit "Update" and voilà, it works.

[ThomasWaldmann]

Interesting. Would you like to make a PR and fix this?

[PhrozenByte]

I just did a quick code check and believe that I've indeed found the issue. However, I don't have a dev setup for nsupdate.info and unfortunately not enough time to set one up. I've just created PR #492, but with completely untested changes. I hope this at least helps a bit, I though it's better than nothing.

Thank you @ThomasWaldmann, keep up with your amazing work! :heart: