Yes, it took longer since I discovered it and I simply wanted to share the insights with you all – thought it makes sense.
Issue was opened yesterday: https://github.com/NLnetLabs/unbound/issues/1404 The fix has been committed today to the maintainer's fork: https://github.com/dwongdev/unbound/commit/16e1e6d375e93e6c00c9b5d20ec4e50fb55d961f It's a kind of "Root Cause Analysis" that delivered it there, and the issue is meanwhile marked as 'completed' (low hanging fruit ;-) ). Hopefully it will soon be merged upstream. Have also tested the patch here now and it works like it should: AXFR/IXFR with multiple DBL zones, no problems at all. Best, Erik Am Montag, dem 16.02.2026 um 11:35 +0000 schrieb Michael Tremer: > Hello Erik, > > This is a *very* long email to tell us about a bug in Unbound. > > Did you report your problem there? > > -Michael > > > On 15 Feb 2026, at 11:58, ummeegge <[email protected]> wrote: > > > > We've identified a compatibility issue with the IPFire Domain > > Blocklist > > (DBL) RPZ zones. These zones contain a ZONEMD record (Type 63) at > > the > > zone apex (e.g., ads.rpz.ipfire.org. 60 IN ZONEMD ...), intended > > for > > data integrity checks. This record causes a critical failure in > > Unbound > > DNS resolver when used with RPZ. > > > > Impact was here: > > > > DNSSEC Failure: Unbound does not ignore the ZONEMD record during > > RPZ processing and mistakenly interprets the zone apex record as a > > policy rule for the root name (.). > > > > Symptoms: After loading more than one IPFire RPZ zone or > > modifying > > the configuration file and restarting/reloading Unbound, the > > resolver > > fails to prime its DNSSEC trust anchor. Typical log entries: > > > > > > unbound: info: rpz: applied [dbl-ads] . rpz-local-data . DNSKEY > > IN > > unbound: info: failed to prime trust anchor -- could not fetch > > DNSKEY rrset . DNSKEY IN > > > > Result: All DNSSEC validation fails, rendering the resolver unable > > to > > resolve any domain names and effectively breaking DNS resolution > > for > > the entire network. > > > > The issue affects more users, as confirmed by Unbound GitHub Issue > > #1404 (verified in Unbound 1.24.1/1.24.2) and potentially also > > #1152. > > > > Technical Cause: > > > > In Unbound's RPZ implementation (services/rpz.c), the function > > rpz_type_ignored() filters out DNSSEC-related records (DNSKEY, > > RRSIG, > > NSEC, etc.) to prevent them from being treated as policy rules. > > ZONEMD > > (RFC 8976, Type 63) is missing from this ignore list – this is IMHO > > an > > Unbound bug. > > > > Loading process: > > > > Unbound reads the apex ZONEMD record. > > > > rpz_type_ignored(63) returns 0 → record gets processed. > > > > strip_dname_origin() removes the zone name → empty label (.). > > > > A rpz-local-data rule for . is created, blocking root DNSKEY > > priming queries. > > > > Note: A detailed analysis and proposed fix (add case > > LDNS_RR_TYPE_ZONEMD: to rpz_type_ignored()) has been submitted to > > Unbound Issue #1404. The root cause lies with Unbound. > > > > Reproduction Steps: > > > > Configure one IPFire DBL RPZ zone (e.g., ads.rpz.ipfire.org) > > following the instructions from > > https://www.ipfire.org/dbl/how-to-use . > > > > Restart Unbound → zone gets cached (may still work initially). > > > > Modify the configuration or add a second zone and restart > > Unbound > > again → priming failure appears in logs. > > > > Tested with Unbound 1.24.1 on IPFire Core 199 and Unbound 1.24.2 on > > Rocky Linux 8.10 (on Unbounds Github). Single zone may load > > initially, > > but fails reliably with config changes or by adding multiple zones. > > > > Current temporary workaround: > > > > Remove ZONEMD records post-download via script (e.g., cron job > > after > > AXFR): > > > > > > sed -i '/IN[[:space:]]\+ZONEMD/d' > > /var/lib/unbound/*.rpz.ipfire.org.zone > > > > Then reload Unbound. > > > > > > While Unbound developers might likely investigate and may fix > > rpz_type_ignored() (Issue #1404), which way should IPFire users go > > until then – since this blocks testing the Beta DBL usage with > > Unbound > > (great project)? Haven´t tested a patched version of Unbound since > > i > > have currently no build environment around but if again, am happy > > to > > test preview versions! > > > > May someone have similar problems or even another workaround or > > potential Fix for this ? > > > > Best regards, > > > > Erik > >
