[GH-ISSUE #257] acme-dns returns NXDOMAIN for A records of existing subdomains rather than NOERROR with empty answer #129

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opened 2026-03-13 15:51:39 +03:00 by kerem · 5 comments

kerem commented

2026-03-13 15:51:39 +03:00

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Originally created by @wiene on GitHub (Feb 18, 2021).
Original GitHub issue: https://github.com/acme-dns/acme-dns/issues/257

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.

Originally created by @wiene on GitHub (Feb 18, 2021). Original GitHub issue: https://github.com/acme-dns/acme-dns/issues/257 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](https://prefetch.net/blog/2016/09/28/the-subtleties-between-the-nxdomain-noerror-and-nodata-dns-response-codes) returning NOERROR with an empty answer would be the correct behaviour.

kerem commented

2026-03-13 15:51:44 +03:00

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@Yannik commented on GitHub (Jun 8, 2021):

Can confirm this issue.

@Yannik commented on GitHub (Jun 8, 2021): Can confirm this issue.

kerem commented

2026-03-13 15:51:49 +03:00

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@Yannik commented on GitHub (Jun 9, 2021):

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

@Yannik commented on GitHub (Jun 9, 2021): I opened a PR to fix this: https://github.com/joohoi/acme-dns/pull/264

kerem commented

2026-03-13 15:51:55 +03:00

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@L3Nerd commented on GitHub (Dec 7, 2021):

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

@L3Nerd commented on GitHub (Dec 7, 2021): We ran into the same problem, do you need any help with the fix?

kerem commented

2026-03-13 15:52:00 +03:00

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@Yannik commented on GitHub (Dec 7, 2021):

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

@Yannik commented on GitHub (Dec 7, 2021): @L3Nerd My fix works perfectly fine, but @joohoi isn't really active on this project anymore and did not merge it (yet).

kerem commented

2026-03-13 15:52:05 +03:00

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@Yannik commented on GitHub (Dec 7, 2021):

Feel free to use it :-)

@Yannik commented on GitHub (Dec 7, 2021): Feel free to use it :-)