knot-dns-users June 2026

knot-dns-users@lists.nic.cz

7 participants
6 discussions

by Smith

Hi I have two questions about this blog post on multi-signers: https://en.blog.nic.cz/2025/05/07/knot-dns-in-a-complex-dnssec-topology/ First, the blog post shows auto-increment SOA serial mode for the zone files in-line with the docs example: ``` zonefile-sync: -1zonefile-load: difference-no-serial journal-content: all ``` This would work fine for me in general, I don't mind zone files being the "source of truth". But the docs has a note "This mode is not suitable if the zone can be modified externally (e.g. DDNS, knotc)." Do I understand correctly that this is because any dynamic changes to the zone get wiped on reboot ? So, for example, if the only external DDNS modification in my environment is DNS-01 for cert issuance, it won't cause me a problem, because those are ephemeral by nature anyway ? This then raises the second question, how would I deal with catlog zones with this concept of multi-signers ? Or are catlog zones too much trouble in a multi-signer environment ? Thank you

3 months, 1 week

Yubikey HSM

by Ulrich Wisser

Hello! Has anybody here got knot to sign with a Yubikey HSM? Asking for a friend! :-) /Ulrich

3 months, 2 weeks

what does "disposal of old contents blocked by outstanding zone transfer" mean?

by Jan-Piet Mens

Hello! I'm testing periodic key rollovers in a playground running Knot DNS 3.5.4 (I am aware that 3.5.5 is out, but this message is also in the current source code) Zone transfers are not being performed, neither incoming nor outgoing (the latter occasionally to see zone content as shown below). At the completion of each signing operation (with purposely very short timings), I see the following debug output: 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, signing zone 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, KSK rollover started 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, next key action, KSK tag 18749, submit at 2026-06-19T08:40:42+0000 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, key, tag 15175, algorithm ECDSAP256SHA256, KSK 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, key, tag 14234, algorithm ECDSAP256SHA256, public, active 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, key, tag 60870, algorithm ECDSAP256SHA256, KSK, public, active 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, key, tag 18749, algorithm ECDSAP256SHA256, KSK, public, active+ 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, signing started 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, successfully signed, serial 94, new RRSIGs 3 2026-06-19T08:39:32+0000 info: [b.net.] DNSSEC, next signing at 2026-06-19T08:40:42+0000 2026-06-19T08:39:32+0000 info: [b.net.] zone file updated, serial 93 -> 94 2026-06-19T08:39:32+0000 debug: [b.net.] disposal of old contents blocked by outstanding zone transfer 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, signing zone 2026-06-19T08:40:42+0000 notice: [b.net.] DNSSEC, KSK submission, waiting for confirmation 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, key, tag 15175, algorithm ECDSAP256SHA256, KSK 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, key, tag 14234, algorithm ECDSAP256SHA256, public, active 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, key, tag 60870, algorithm ECDSAP256SHA256, KSK, public, active 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, key, tag 18749, algorithm ECDSAP256SHA256, KSK, public, ready, active+ 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, signing started 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, successfully signed, serial 95, new RRSIGs 6 2026-06-19T08:40:42+0000 info: [b.net.] DNSSEC, next signing at 2026-07-03T06:45:11+0000 2026-06-19T08:40:42+0000 info: [b.net.] zone file updated, serial 94 -> 95 2026-06-19T08:40:42+0000 debug: [b.net.] disposal of old contents blocked by outstanding zone transfer 2026-06-19T08:40:42+0000 info: [b.net.] DS check, outgoing, remote 127.0.0.2@53 TCP, key p01., KSK submission check: negative 2026-06-19T08:40:52+0000 info: [b.net.] DS push, outgoing, remote 127.0.0.2@53 TCP, key p01., success 2026-06-19T08:41:42+0000 info: [b.net.] DS check, outgoing, remote 127.0.0.2@53 TCP, key p01., KSK submission check: positive 2026-06-19T08:41:42+0000 notice: [b.net.] DNSSEC, KSK submission, confirmed The zone itself is trivially short: $ dig -p 5340 @127.0.0.1 b.net AXFR +noall +answer +onesoa | ldns-read-zone -s b.net. 60 IN SOA ns.b.net. root.b.net. 100 10800 3600 604800 3600 www.b.net. 60 IN HTTPS 0 b.net. ns.b.net. 60 IN AAAA 2001:db8:2::4444 ns.b.net. 60 IN A 192.0.2.42 b.net. 60 IN NSEC3PARAM 1 0 0 - b.net. 60 IN DNSKEY 257 3 13 zmXFV/KHpRk/E6l7oiRg2f2M+YpWxGqHFJtHmsAFl4KAxZPeiL2VIFLswpGnrwxO47//vz/I1VqsLhmUz9k35A== ;{id = 18749 (ksk), size = 256b} b.net. 60 IN DNSKEY 256 3 13 x9PPypMDeXRarFtYwxT5uvQjE/DHQd6g+NcF5FkVGDhz/+Xq2r3ZDfLXYUjW1ivoZHstnH5hSC4znp9oghlLfw== ;{id = 38612 (zsk), size = 256b} b.net. 60 IN TXT "DNS is innocent" b.net. 60 IN NS ns.b.net. and the IMO relevant bits of the configuration are: acl: - id: all_xfr address: [ 127.0.0.1 ] action: [ transfer, notify ] submission: - id: pdns_submission check-interval: 60s parent: pdns_remote parent-delay: 10s template: - id: default storage: "/tmp/zones" zonefile-load: difference file: "%s" policy: - id: autoFAST keystore: pemstore single-type-signing: off manual: off algorithm: ecdsap256sha256 ksk-shared: off ksk-lifetime: 1h zsk-lifetime: 2h delete-delay: 1h propagation-delay: 10s nsec3: on nsec3-iterations: 0 nsec3-salt-length: 0 nsec3-salt-lifetime: 0 cds-cdnskey-publish: rollover zone-max-ttl: 60s ksk-submission: pdns_submission ds-push: pdns_remote zone: - domain: b.net dnssec-signing: on dnssec-policy: autoFAST acl: [ all_xfr ] Ought I be worried about "disposal of old contents blocked by outstanding zone transfer"? I don't think I've noticed that before. A second zone which uses the same policy shows the same behaviour. Best regards, -JP

3 months, 3 weeks

Knot DNS 3.5.5 release

by Daniel Salzman

Hello Knot DNS users, CZ.NIC has released Knot DNS 3.5.5. This is a bug fix version with some improvements. Changelogs: https://gitlab.labs.nic.cz/knot/knot-dns/raw/v3.5.5/NEWS Download: https://www.knot-dns.cz/download/ Documentation: https://www.knot-dns.cz/documentation/ Support: https://www.knot-dns.cz/support/ Regards, Daniel

3 months, 3 weeks

[BUG] AXFR responses missing AA bit (RFC 5936 violation) in Knot 3.5.x

by Mateusz Masłowski

Hello, I would like to report a bug in Knot DNS 3.5.x where AXFR responses do not have the Authoritative Answer (AA) bit set, which appears to violate RFC 5936 §2.2. Affected versions tested: - 3.5.3 - 3.5.4 Packages tested: - cznic.1~bookworm Summary RFC 5936 §2.2 states: "Each DNS message returned by the AXFR server MUST have the AA bit set to 1." However, Knot DNS sends AXFR responses with flags set to qr only. The AA bit is not set in any of the messages in the transfer stream. As a result, strict secondary DNS servers, notably Windows Server DNS, reject such responses as invalid and abort the zone transfer. Expected behavior AXFR response messages should have the AA bit set. Expected flags: qr aa Actual behavior AXFR response messages have only the QR bit set. Actual flags: qr Possible root cause The function axfr_process_query() in src/knot/nameserver/axfr.c does not appear to call knot_wire_set_aa(). By contrast, the normal query path, via solve_answer() in internet.c, does set the AA bit, so SOA, A, and other authoritative responses are returned correctly. The AXFR code path appears to bypass this logic. Minimal reproducer dig @<knot-master> +tcp AXFR <zone> | head -2 Observed output: ;; flags: qr; The AA bit is missing. This can also be verified with tcpdump: byte 3 of each DNS message in the AXFR stream has value 0x80 / QR only, instead of 0x84 / QR + AA. -- Best regards, Mateusz Masłowski

4 months

Glue Record Problem

by Stefan Estada

Hi all I am having trouble forwarding a subdomain since I upgraded to the latest knot. For a couple of years I have been running a custom DNS server under dynamic.estada.ch that the clients find via my regular infrastructure. On my primary zone I have these records, but knot appears to answer weirdly: *estada.ch.zone* dynamic.estada.ch. 3600 A 185.194.239.135 dynamic.estada.ch. 3600 AAAA 2a0a:51c0::12b dynamic.estada.ch. 3600 NS dynamic.estada.ch. kdig AAAA dynamic.estada.ch @ns1.estada.ch ;; ->>HEADER<<- opcode: QUERY; status: NOERROR; id: 29173 ;; Flags: qr rd; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 3 ;; EDNS PSEUDOSECTION: ;; Version: 0; flags: ; UDP size: 1232 B; ext-rcode: NOERROR ;; QUESTION SECTION: ;; dynamic.estada.ch. IN AAAA ;; AUTHORITY SECTION: dynamic.estada.ch. 3600 IN NS dynamic.estada.ch. ;; ADDITIONAL SECTION: dynamic.estada.ch. 3600 IN A 185.194.239.135 dynamic.estada.ch. 3600 IN AAAA 2a0a:51c0::12b But public servers don't get the glue records: kdig AAAA dynamic.estada.ch @9.9.9.9 ;; ->>HEADER<<- opcode: QUERY; status: SERVFAIL; id: 63899 ;; Flags: qr rd ra; QUERY: 1; ANSWER: 0; AUTHORITY: 0; ADDITIONAL: 1 ;; EDNS PSEUDOSECTION: ;; Version: 0; flags: ; UDP size: 1232 B; ext-rcode: NOERROR ;; QUESTION SECTION: ;; dynamic.estada.ch. IN AAAA The trouble is that most resolvers are now unable to resolve the domain as the AAAA and A queries still get answered with NS + additional A+AAAA. Is there a configuration option to tell knot to actually respond with the A or AAAA record when asked? Also ANY, TXT, or CAA queries behave the same as NS queries: kdig ANY dynamic.estada.ch @ns1.estada.ch ;; ->>HEADER<<- opcode: QUERY; status: NOERROR; id: 14419 ;; Flags: qr rd; QUERY: 1; ANSWER: 0; AUTHORITY: 1; ADDITIONAL: 3 ;; EDNS PSEUDOSECTION: ;; Version: 0; flags: ; UDP size: 1232 B; ext-rcode: NOERROR ;; QUESTION SECTION: ;; dynamic.estada.ch. IN ANY ;; AUTHORITY SECTION: dynamic.estada.ch. 3600 IN NS dynamic.estada.ch. ;; ADDITIONAL SECTION: dynamic.estada.ch. 3600 IN A 185.194.239.135 dynamic.estada.ch. 3600 IN AAAA 2a0a:51c0::12b I am happy for any pointers you may have. Cheers, Stefan

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knot-dns-users June 2026