title: DNS resolution fails from one resolver but succeeds with another
body: <p>So the following request fails:</p>
  <p><code>dig @81.134.98.15 aega14.ooo.xn--nxa2a.com</code></p>
  <pre><code>; &lt;&lt;&gt;&gt; DiG 9.10.3-P4-Ubuntu &lt;&lt;&gt;&gt; @81.134.98.15 aega14.ooo.xn--nxa2a.com
  ; (1 server found)
  ;; global options: +cmd
  ;; Got answer:
  ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: SERVFAIL, id: 39842
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
  
  ;; OPT PSEUDOSECTION:
  ; EDNS: version: 0, flags:; udp: 512
  ;; QUESTION SECTION:
  ;aega14.ooo.xn--nxa2a.com.      IN      A
  
  ;; Query time: 53 msec
  ;; SERVER: 81.134.98.15#53(81.134.98.15)
  ;; WHEN: Fri Nov 06 23:52:21 GMT 2020
  ;; MSG SIZE  rcvd: 53
  </code></pre>
  <p>but this one succeeds:</p>
  <p><code>dig @8.8.8.8 aega14.ooo.xn--nxa2a.com</code></p>
  <pre><code>; &lt;&lt;&gt;&gt; DiG 9.10.3-P4-Ubuntu &lt;&lt;&gt;&gt; @8.8.8.8 aega14.ooo.xn--nxa2a.com
  ; (1 server found)
  ;; global options: +cmd
  ;; Got answer:
  ;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 42602
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
  
  ;; OPT PSEUDOSECTION:
  ; EDNS: version: 0, flags:; udp: 512
  ;; QUESTION SECTION:
  ;aega14.ooo.xn--nxa2a.com.      IN      A
  
  ;; ANSWER SECTION:
  aega14.ooo.xn--nxa2a.com. 0     IN      A       70.56.46.71
  
  ;; Query time: 50 msec
  ;; SERVER: 8.8.8.8#53(8.8.8.8)
  ;; WHEN: Fri Nov 06 23:54:17 GMT 2020
  ;; MSG SIZE  rcvd: 69
  </code></pre>
  <p>The first request is using the dns resolver of my ISP, and it looks like is the only resolver through which the dns resolution fails. Any ideas of what could be the problem? It is also noted that <code>dig @81.134.98.15 google.com</code> succeeds and I have tried with multiple hostnames like: aega14, aega15, ... so it doesn't appear to be a caching problem.</p>
  <p>it is noted that the dns server is configured to respond to arbitrary queries in the form: *.ooo.xn--nxa2a.com.</p>