knot-resolver-users Prosinec 2019

knot-resolver-users@lists.nic.cz

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Re: [knot-resolver-users] knot-resolver-users Digest, Vol 93, Issue 1

by Milan Jeskynka Kazatel

Hello Petr, many thanks for your hint regarding modules.unload('bogus_log') I´m still facing the service kresd@1 crashes without any obvious reasons. Today I did a second try to upgrade to Knot Resover to version 4.2.2 and the upgrade seems to be ok, service can start without any difficulties. It runs as expected more than 3,5 hour, but unfortunately, it starts to write in the log the same messages as was reported in my previous post and the service get restart by itself. Every restarts couse a new sevice PID in /var/cache/ knot-resolver/tty, the old one was not correctly finished and the whole operating system goes to a visible slowdown. I don´t know how to do an exact sevice crashdump file, but I can provide any log messages if needed. I unload the bogus_log. The service runs now just a while. My usual dns queries throughput is around 700qps and I have only one PID in /var/cache/knot-resolver/tty as usual. Regards, -- Smil Milan Jeskyňka Kazatel ---------- Původní e-mail ---------- Od: knot-resolver-users-request(a)lists.nic.cz Komu: knot-resolver-users(a)lists.nic.cz Datum: 25. 10. 2019 11:53:00 Předmět: knot-resolver-users Digest, Vol 93, Issue 1 "Send knot-resolver-users mailing list submissions to knot-resolver-users(a)lists.nic.cz To subscribe or unsubscribe via the World Wide Web, visit https://lists.nic.cz/mailman/listinfo/knot-resolver-users or, via email, send a message with subject or body 'help' to knot-resolver-users-request(a)lists.nic.cz You can reach the person managing the list at knot-resolver-users-owner(a)lists.nic.cz When replying, please edit your Subject line so it is more specific than "Re: Contents of knot-resolver-users digest..." Today's Topics: 1. Re: DNSSEC validation failure logging on Centos 7 Knot Resolver, version 4.2.0 (Milan Jeskynka Kazatel) 2. Re: DNSSEC validation failure logging on Centos 7 Knot Resolver, version 4.2.0 (Petr Špaček) 3. HTTP module after upgrade from Knot DNS Resolver, version 2.3.0 to Knot Resolver, version 4.2.0 (Milan Jeskynka Kazatel) ---------------------------------------------------------------------- Message: 1 Date: Tue, 22 Oct 2019 14:27:30 +0200 (CEST) From: "Milan Jeskynka Kazatel" <KazatelM(a)seznam.cz> To: <knot-resolver-users(a)lists.nic.cz> Subject: Re: [knot-resolver-users] DNSSEC validation failure logging on Centos 7 Knot Resolver, version 4.2.0 Message-ID: <1XT.6dmr.1vQ4HW9UcyY.1ThlMo(a)seznam.cz> Content-Type: text/plain; charset="utf-8" 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 (https://knot-resolver.readthedocs.io/en/stable/daemon.html#dnssec-config). *** 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(a)1.service watchdog timeout (limit 10s)! Oct 22 14:03:22 dnstestserver systemd[1]: kresd(a)1.service: main process exited, code=killed, status=6/ABRT Oct 22 14:03:22 dnstestserver systemd[1]: Unit kresd(a)1.service entered failed state. Oct 22 14:03:22 dnstestserver systemd[1]: kresd(a)1.service failed. Oct 22 14:03:22 dnstestserver systemd[1]: kresd(a)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 ---------- Původní e-mail ---------- Od: Milan Jeskynka Kazatel <KazatelM(a)seznam.cz> Komu: knot-resolver-users(a)lists.nic.cz Datum: 22. 10. 2019 13:33:46 Předmět: DNSSEC validation failure logging on Centos 7 Knot Resolver, version 4.2.0 "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 "

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Knot Resolver 4.2.2

by Milan Jeskynka Kazatel

Hello Team, I would like to ask why my new version of Knot Resolver does many records of "DNSSEC validation failure szn-broken-dnssec.cz. DNSKEY" I tried to compare results with my second resolver on Unbound 1.9.4 where I' m able to receive an answer by command #unbound-control lookup szn-broken- dnssec.cz but no answer via dig command #dig szn-broken-dnssec.cz The same result via dig is on the server with new Knot Resolver 4.2.2 As was mentioned in your documentation https://knot-resolver.readthedocs.io/ en/stable/modules.html#dnssec-validation-failure-logging (https://knot-resolver.readthedocs.io/en/stable/modules.html#dnssec-validati…) I tried the https://dnsviz.net/d/szn-broken-dnssec.cz/dnssec/ (https://dnsviz.net/d/szn-broken-dnssec.cz/dnssec/) and the result is BOGUS, then should I be worried about this message in my log? Thanks for any answer, best regards -- Smil Milan Jeskyňka Kazatel

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Knot Resolver 4.3.0

by Tomas Krizek

Dear Knot Resolver users, Knot Resolver 4.3.0 has been released! Security - CVE-2019-19331 ------------------------- - fix speed of processing large RRsets (DoS, #518) - improve CNAME chain length accounting (DoS, !899) Bugfixes -------- - http module: use SO_REUSEPORT (!879) - systemd: kresd@.service now properly starts after network interfaces have been configured with IP addresses after reboot (!884) - sendmmsg: improve reliability (!704) - cache: fix crash on insertion via lua for NS and CNAME (!889) - rpm package: move root.keys to /var/lib/knot-resolver (#513, !888) Improvements ------------ - increase file-descriptor count limit to maximum allowed value (hard limit; !876) - watchdog module: support testing a DNS query (and switch C -> lua; !878, !881) - performance: use sendmmsg syscall towards clients by default (!877) - performance: avoid excessive getsockname() syscalls (!854) - performance: lua-related improvements (!874) - daemon now attempts to drop all capabilities (!896) - reduce CNAME chain length limit - now <= 12 (!899) Full changelog: https://gitlab.labs.nic.cz/knot/knot-resolver/raw/v4.3.0/NEWS Sources: https://secure.nic.cz/files/knot-resolver/knot-resolver-4.3.0.tar.xz GPG signature: https://secure.nic.cz/files/knot-resolver/knot-resolver-4.3.0.tar.xz.asc Documentation: https://knot-resolver.readthedocs.io/en/v4.3.0/ -- Tomas Krizek PGP: 4A8B A48C 2AED 933B D495 C509 A1FB A5F7 EF8C 4869

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Configuring kresd to query multiple nameservers and return the first affirmative response?

by Bernd Wechner

I wonder if this is possible. The Knot Resolver certainly looks powerful, and I use it on my Omnia Router of course. But the documentation <https://knot-resolver.readthedocs.io/en/stable/index.html>which I have perused and read quickly, hasn't helped me understand this alas. It leaves me with a couple of interesting questions: 1. How are nameservers configured? Interestingly my running instance of kresd is on the Omnia and it receives nameservers via a dhcp request on my ISP I imagine, though I don't see them in /etc/resolv.conf 2. Is it possible configure a number of nameservers on a the basis of query them all (akin to dnsmasq's --all-servers) and return the first affirmative response? My interest is acutely related to: https://superuser.com/questions/1505755/can-one-configure-name-resolution-t… And I'd happily use kresd on my local machine(s) as well as on my LAN DNS (The Omnia) to help resolve names on my .lan while on a VPN! Regards, Bernd.

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knot-resolver-users Prosinec 2019