DIG command returns SERVFAIL status

[afroissard]

Hi,

I installed Unbound version 1.13.1 on Ubuntu 22.04.5 LTS.
First thing first, when I dig example.com @127.0.0.1 I don't get any ANSWER section :

If I try a dig command without being specific about the resolver I want to use, it works well :

If I try with any other resolver like Quad9 it works well too :

I checked if the Unbound service was running properly and that was the case :

Can you please put me in the right direction about the issue I'm facing ?

Thanks !

Alexandre

[wcawijngaards]

Perhaps try looking at the logs that unbound produces. With verbosity: 4 (a value from 0 to higher) and like logfile: "unbound.log" , or look in the system logs. With log-servfail: yes unbound prints messages about the servfail that happened.

[afroissard]

Thank you for very reponsive answer !

I increased the verbosity level to 4 :

When I try the same command I used at the very beginning, this is what I get :

If I give a look at journalctl -n 100, this is what I get :

It looks like I've got a problem with UDP and something starting with "2001:xxx:xxx:"

What do you think ?

Thank you

[wcawijngaards]

It looks like ipv6 is not routed for the machine, with the option, do-ip6: no those errors go away.

Likely unbound also tries to resolve using IPv4, and this must also be failing since the answer is servfail. For that look at the logs, right now it only shows the error category, perhaps that ended up in different logfile that is not sys log, depends if logfile was configured. Then it likely says what the IPv4 attempts did, and also the log-servfail: yes output that describes, more shortly, what went wrong.