Hello Team, 

I found it, it is described in the Upgrading guide, 
DNSSEC validation is now turned on by default. If you need to disable it, see Trust anchors and DNSSEC.

***

Since version 4.0, DNSSEC validation is enabled by default. This is secure default and should not be changed unless absolutely necessary.

Options in this section are intended only for expert users and normally should not be needed.

If you really need to turn DNSSEC off and are okay with lowering security of your system by doing so, add the following snippet to your configuration file.

-- turns off DNSSEC validation
trust_anchors.remove('.').
***

Anyway, if it is enabled by default, how to prevent the "DNSSEC validation failure" spamming in the log and increasing the  I/O operation on the system?
For me now is the service in the unstable condition. My kresd@1 is crashing and restarting in the row. Please, any advice?

I modify the server name and the domain, but still it is a live log output.

Oct 22 14:02:51 dnstestserver kresd[15877]: DNSSEC validation failure example.com DNSKEY
Oct 22 14:02:58 dnstestserver kresd[15877]: DNSSEC validation failure example.com DNSKEY
Oct 22 14:03:08 dnstestserver kresd[15877]: DNSSEC validation failure example.com DNSKEY
Oct 22 14:03:18 dnstestserver systemd[1]: kresd@1.service watchdog timeout (limit 10s)!
Oct 22 14:03:22 dnstestserver systemd[1]: kresd@1.service: main process exited, code=killed, status=6/ABRT
Oct 22 14:03:22 dnstestserver systemd[1]: Unit kresd@1.service entered failed state.
Oct 22 14:03:22 dnstestserver systemd[1]: kresd@1.service failed.
Oct 22 14:03:22 dnstestserver systemd[1]: kresd@1.service holdoff time over, scheduling restart.
Oct 22 14:03:22 dnstestserver systemd[1]: Cannot add dependency job for unit kresd.service, ignoring: Unit not found.
Oct 22 14:03:22 dnstestserver systemd[1]: Stopped Knot Resolver daemon.
Oct 22 14:03:22 dnstestserver systemd[1]: Starting Knot Resolver daemon...
Oct 22 14:04:07 dnstestserver kresd[16468]: [http] created new ephemeral TLS certificate
Oct 22 14:04:07 dnstestserver systemd[1]: Started Knot Resolver daemon.
Oct 22 14:04:07 dnstestserver kresd[16468]: [ta_update] refreshing TA for .
Oct 22 14:04:07 dnstestserver kresd[16468]: [ta_update] key: 20326 state: Valid
Oct 22 14:04:07 dnstestserver kresd[16468]: [ta_update] next refresh for . in 24 hours
Oct 22 14:04:09 dnstestserver kresd[16468]: DNSSEC validation failure example.com DNSKEY
...
Best regards.
--
Smil Milan Jeskyňka Kazatel


Hello Team,

I would like to know if the "DNSSEC validation failure logging" is enabled by DEFAULT in version 4.2.0. on Centos 7.

I do not have any explicit call for this module - as is described in the documentation like this: modules.load('bogus_log'), nevertheless, I´m facing a huge report in the system log regarding DNSSEC validation failure somedomainname. DNSKEY

In the configuration, I´m using the 'http' module and module 'stats', can it be relevant?

kresd.conf
-- Load Useful modules
modules = {
        'policy',   -- Block queries to local zones/bad sites
        'view',     -- Handle requests by source IP
        'stats',    -- Track internal statistics
        'hints',    -- Add static records to resolver
}

-- load HTTP module with defaults (self-signed TLS cert)
modules.load('http')
http.config()

How can I disable DNSSEC validation failure logging?

best regards,
--
Smil Milan Jeskyňka Kazatel