Internet Connection to Server via Hostname Fails - IP works

Hi There,
I hope this is the correct category. :slight_smile:

I have done a ton of research to get my little server to /almost/ working order.
While I learned a lot, I am far from a Linux or MineOS Pro, so please feel free to point out any mistakes.

Heres my Problem:
I cannot connect to my minecraft Server from the internet when I use it’s hostname. Connecting via IPv6 works.
Error Message: “Failed to connect to the server - Connection timed out: no further information”

General infromation:
-I run MineOS as a VM on my Home Server running Proxmox.
-Due to ISP limitations, I have to use dynDNSv6 to make my services accessible from the internet.
(works fine, I use a domain I own, the Domain providers inbuild dynDNSv6 service and ddclient)

My first thought was DNS but I can reach my webui from the internet via hostname.
I can also connect to my server via IPv6 and hostname from my LAN. (in this case my local DNS, pi-hole, is responsible for name resolution)

As you can see in the “netstat -ntlp” output, my server is listening on the relevant ports. So this shouldnt be an issue either.
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0* LISTEN 548/sshd: /usr/sbin
tcp 0 0* LISTEN 1519/master
tcp 0 0* LISTEN 620/shellinaboxd
tcp 0 0* LISTEN 535/stunnel4
tcp 0 0* LISTEN 657/mariadbd
tcp6 0 0 :::22 :::* LISTEN 548/sshd: /usr/sbin
tcp6 0 0 :::443 :::* LISTEN 1523/node
tcp6 0 0 :::25565 :::* LISTEN 1556/java
tcp6 0 0 :::12320 :::* LISTEN 533/stunnel4

I really don’t know how to continue troubleshooting and what to look at next, any input is welcome. Thanks in advance

I did some further testing and setup a Vanilla server following the official Wiki trying to see if i had the same result in another distro.
Doing so I found the problem.
When setting up ddclient it defaults to IPv4. That means, the dynDNS entry had an A Record for an IPv4 Adress (one from a private network).
After the changes to the ddclient.conf the IPV4 Adress was never updated, but also was not removed.
The AAAA Record (IPv6) was just added.

Looks like some Software (i.e. browser I used to acces Webui) was smart enough to try the IPv6 Adress from the AAAA Record if they cannot reach the A Record IPv4.
Other Software (i.e. Minecraft Launcher) defaults just doesnt bother looking at AAAA Records if there is an A Record. no matter if reachable or not.

I manually reset the dynDNS information with my provider and ddclient -force an update.
=> no A record, AAAA Record = IPv6
It’s working now.

Sorry for wasting your time. (and mine XD)