Hello Knot DNS users,
Knot DNS supports TCP Fast Open (when configured) in both the server and client roles for several years.
However, we have not observed any performance or other improvements from this technology so far. Since
removing it would simplify the code, I'm considering dropping the support for it. Is there anyone who would
miss TFO in Knot DNS?
For better XFR efficiency between Knots, https://www.knot-dns.cz/docs/latest/singlehtml/index.html#remote-pool-limit
works much better.
Thanks,
Daniel
Greetings,
One thing I’m not sure about is exactly what happens when we run `knotc zone-ksk-submitted`?
Our parent zones don’t support CDS/CDNSKEY, so we manually update DS records and then
run `knotc zone-ksk-submitted`. It seems to me that as soon as we run it, the retiring of the outgoing
KSK key starts and it’s removed from the DNSKEY RRset. Is that correct?
I’d like to be sure, because as it is, I wait at least the TTL of the DS record before running zone-ksk-submitted,
if I run it right away and knot removes the key immediately from the DNSKEY RRset, then caching resolvers
will invalidate the zone.
The docs for knotc say:
Use when the zone's KSK rollover is in submission phase. By calling this command the user confirms manually that the parent zone contains DS record for the new KSK in submission phase and the old KSK can be retired. (#)
Reading the docs, I would think I should run zone-ksk-submitted as soon as the new DS record has been
published in the parent, but then knot would need to know to wait for the TTL of the DS record before
removing the key.
Should I wait before running zone-ksk-submitted, or is there a config option I’m missing to tell knot
the ds ttl?
.einar
Hi, I'm having issues with ACL's and DNS updates and multiple DNS servers.
I use DNS-01 for TLS letsencrypt and AXFR between the servers, but for some reason acme.sh is not working for a new server with "NOTAUTH" failures.
(I give acme.sh export KNOT_SERVER='souseiseki.middlendian.com' so that it uses the master and that works fine on the master and another server, but for some reason on the new one there is an ACL
related failure?);
[Thu 04 Dec 2025 21:53:49 AEDT] Adding _acme-challenge.middlendian.com. 60 TXT "<snip>"
;; ->>HEADER<<- opcode: UPDATE; status: NOTAUTH; id: 42945
;; Flags: qr; ZONE: 1; PREREQ: 0; UPDATE: 0; ADDITIONAL: 1
;; ZONE SECTION:
;; middlendian.com. IN SOA
;; ADDITIONAL DATA:
;; TSIG PSEUDOSECTION:
acme_key. 0 ANY TSIG hmac-sha512. 1764845629 300 64 <snip> 42945 NOERROR 0
;; ERROR: update failed with error 'NOTAUTH'
knsupdate works with the set key to the master;
knsupdate
knsupdate> server souseiseki.middlendian.com
knsupdate> key hmac-sha512:acme_key:<snip>
knsupdate> zone middlendian.com.
knsupdate> add test.middlendian.com. 300 TXT test
knsupdate> send
knsupdate> answer
But, the ACL seems to have problems, as DNS updates fail if attempted via any secondary server?;
knsupdate
knsupdate> server hinaichigo.middlendian.com
knsupdate> key hmac-sha512:acme_key:<snip>
knsupdate> zone middlendian.com.
knsupdate> del test.middlendian.com TXT
knsupdate> send
;; ->>HEADER<<- opcode: UPDATE; status: NOTAUTH; id: 14970
;; Flags: qr; ZONE: 1; PREREQ: 0; UPDATE: 0; ADDITIONAL: 1
;; ZONE SECTION:
;; middlendian.com. IN SOA
;; ADDITIONAL DATA:
;; TSIG PSEUDOSECTION:
acme_key. 0 ANY TSIG hmac-sha512. 1764844872 300 64 <snip> 14970 NOERROR 0
;; ERROR: update failed with error 'NOTAUTH'
Knot on souseiseki outputs an error to syslog; "ACL, denied, action update, remote 125.63.60.124@38966 TCP"
but that isn't helpful debug output, as it does not say why the ACL was denied.
IP address related matching could be a problem, but reviewing the documentation, it seems to state that IP addresses are not considered in ACL's unless listed in the ACL?
Does anyone know what the issue is and otherwise how do I debug it?
All the servers have the same ACL key set;
/etc/knot/acme.key;
key:
- id: acme_key
algorithm: hmac-sha512
secret: <snip>
souseiseki (master);
remote:
- id: suigintou
address: [ 180.150.27.133@53, 2403:5806:e8d0::dead:beef:cafe@53 ]
- id: hinaichigo
address: 125.63.60.124@53
include: "/etc/knot/acme.key"
acl:
- id: acme_acl
key: acme_key
action: update
zone:
- domain: middlendian.com
dnssec-signing: on
acl: acme_acl
notify: [ suigintou, hinaichigo ]
hinaichigo (secondary);
remote:
- id: master
address: 144.6.197.157@53
acl:
- id: acme_acl
key: acme_key
action: [update, notify]
zone:
- domain: middlendian.com
master: master
acl: acme_acl
--
Kind Regards, DiffieHellman
Hi,
In our setup, we have one active signer and one backup signer. Both use
softhsm, but only the active signer does automatic key management.
There is an hourly cron job that syncs keys from active to backup signer.
It runs knotc zone-backup on the active signer, only backing up the kaspdb.
It then syncs the files over to the secondary and runs knotc zone-restore.
This has been running for a few years now without problems.
These last two weeks we’ve been performing algorithm rollovers for
some of our zones, and after we run `knotc zone-ksk-submitted nic.is`
we start seeing these errors when the zone-restore is run on the backup:
error: [nic.is.] zone event 'backup/restore' failed (already exists)
warning: [nic.is.] zone restore failed (already exists)
warning: [nic.is.] restore, key copy failed (already exists)
I searched the knot dns source code, but couldn't find where these
errors are output. Like I said, we’ve been running like this for a few
years, doing regular ZSK rollovers, and a few KSK rollovers, without
problems. There’s something about the algorithm rollover that
causes this problem with our setup.
I assume I can just delete the keys on the secondary and sync again,
but I want to understand what causes these errors so we can avoid them
or at best document them in our process.
.einar
