acme-dns returns NXDOMAIN for A records of existing subdomains rather than NOERROR with empty answer

[wiene]

If acme-dns is accidentally asked for an A record rather than a TXT record of an existing subdomain, it returns NXDOMAIN which might be cached for one day (due to SOA settings). If it is cached, the caching server keeps responding NXDOMAIN even if the initial error is corrected and the corresponding TXT record is requested.

A simple (pseudo-)reproducer is:

[user@host ~]$ host -t A f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com acme-dns.example.com
Using domain server:
Name: acme-dns.example.com
Address: 1.2.3.4#53
Aliases: 

Host f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com not found: 3(NXDOMAIN)

[user@host ~]$ host -t TXT f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com acme-dns.example.com
Using domain server:
Name: acme-dns.example.com
Address: 1.2.3.4#53
Aliases: 

f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com descriptive text "somestring"

[user@host ~]$ host f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com        
Host f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com not found: 3(NXDOMAIN)

[user@host ~]$ host -t TXT f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com
Host f47eea99-06c9-4a60-8134-7beac011e27f.acme.example.com not found: 3(NXDOMAIN)

According to this blog article returning NOERROR with an empty answer would be the correct behaviour.

[Yannik]

Can confirm this issue.

[Yannik]

I opened a PR to fix this: https://github.com/joohoi/acme-dns/pull/264

[L3Nerd]

We ran into the same problem, do you need any help with the fix?

[Yannik]

@L3Nerd My fix works perfectly fine, but @joohoi isn't really active on this project anymore and did not merge it (yet).

[Yannik]

Feel free to use it :-)