Hello Adolf,

> On 27 Jan 2026, at 16:33, Adolf Belka <[email protected]> wrote:
> 
> Hi Michael,
> 
> On 27/01/2026 17:10, Michael Tremer wrote:
>> Hello Adolf,
>> Interesting case. I tried to resolve the domain at my office and that seems 
>> to be working just fine.
>> They don’t even use DNSSEC, so any problems from that can be ruled out.
>> Anything more in the logs? It could have been the IP blocklists blocking 
>> communication.
> 
> I checked out disabling the IP Blocklists, IPS and Web Proxy and still it was 
> blocked if I was using recursor mode.
> 
> I just came home and the standard dns servers have been running for the last 
> 5 hours (so not recursor mode) and tried accessing the login page and it 
> worked fine.
> 
> I then changed back to the recursor mode, cleared the browser cache and 
> immediately the login page failed to load. The message I get is
> 
> 
> Unable to connect
> Firefox can’t establish a connection to the server at auth.opgroen.nl.
> Error code: 503 Service Unavailable
>    The site could be temporarily unavailable or too busy. Try again in a few 
> moments.
>    If you are unable to load any pages, check your computer’s network 
> connection.
>    If your computer or network is protected by a firewall or proxy, make sure 
> that Firefox is permitted to access the web.
> 
> I then turned back on the listed dns servers, cleared the browser cache and 
> the login page worked immediately.
> 
> So the issue is consistent.
> 
>> If you have been testing DBL, that can probably be ruled out because you 
>> don’t resolve anything. The domain is not listed: 
>> https://www.ipfire.org/dbl/search?q=auth.opgroen.nl
> 
> For this investigation I had disabled the URL Filter.
> 
> I looked in the DS logs for all of January and only found a single entry
> 
> 09/21:27:54 unbound: [2020:0]  error: SERVFAIL <opgroen.nl. A IN>: misc 
> failure

Hmm, this is not a very useful error message. I just checked the Unbound source 
and this seems to be coming from the validator module - the one for DNSSEC 
although the domain does not use DNSSEC at all.

Can you try to increase the val-log-level and see if Unbound can tell us more?

  
https://unbound.docs.nlnetlabs.nl/en/latest/manpages/unbound.conf.html#unbound-conf-val-log-level

> This was combined with a lot of other fails but this was when there was a 
> problem with my ISP connection and before the time that I was trying to login 
> to my insurer.
> 
> So as far as I can find other than the Unable to resolve A/AAAA record 
> message I have not found any other message related to opgroen.nl in my logs 
> for the whole of January which makes it very strange, especially as I can 
> turn the problem on and off by using recursor mode or using listed dns 
> servers.
> 
> Anyway, I have a working system now with listed dns servers so will stay 
> using that for the future.
> 
> Regards,
> 
> Adolf.
> 
>> -Michael
>>> On 27 Jan 2026, at 10:28, Adolf Belka <[email protected]> wrote:
>>> 
>>> Hi All,
>>> 
>>> Thought I would communicate about a problem I have been having.
>>> 
>>> I needed to login to my Insurance web site. I could access all the web 
>>> pages I wanted but when trying to login I always got a 503 not available or 
>>> a timeout. This was happening for the last three days.
>>> 
>>> I disabled the web proxy, IPS and the IP Blocklists functions but none of 
>>> it made any difference. Also cleared all caches I could find. No 
>>> difference. All other web sites and logins worked fine.
>>> 
>>> This morning looking through various logs I found the following message.
>>> 
>>> INFO: Unable to resolve A/AAAA record of queried destination 
>>> 'auth.opgroen.nl', returning ERR...
>>> 
>>> I was using the Recursor mode with my IPFire DNS but I still had 5 DNS 
>>> servers listed, just not enabled.
>>> I therefore enabled them and immediately I was able to get the login screen 
>>> to display.
>>> 
>>> I then reverted back to the recursor mode and the login stayed worked. Also 
>>> after waiting 5 minutes. I then cleared the browser cache and the login 
>>> page failed to be found.
>>> 
>>> I then enabled just one DNS server - recursor01.dns.lightningwirelabs.com - 
>>> on the DNS page and the login page worked again.
>>> 
>>> Also tested clearing the browser cache and the login page still being shown.
>>> 
>>> Working now for over 15 minutes. That is compared to not working at all 
>>> once over the last three days trying numerous times.
>>> 
>>> So there seems to be something about my insurance providers login page that 
>>> doesn't want to work well with the Recursor Mode, although everything else 
>>> has worked fine.
>>> 
>>> So I now have a selected DNS site and thankfully I am able to access the 
>>> login page again but thought I would let you know what I found.
>>> 
>>> Regards,
>>> 
>>> Adolf.
>>> 
>>> 
> 


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