On Thu, Dec 14, 2023 at 10:04:02AM +0000, Chris Green wrote: > On Wed, Dec 13, 2023 at 08:59:05PM +0000, Simon Kelley wrote: > > On 13/12/2023 15:25, Chris Green wrote: > > > I run dnsmasq version 2.89 on my laptop > > > which is running [x]ubuntu 23.04. > > > > > > I have systemd.resolvd disabled. > > > > > > I'm occasionally seeing the following error when getting a host's IP:- > > > > > > chris$ host homepi > > > ;; communications error to 127.0.0.1#53: timed out > > > homepi has address 192.168.1.113 > > > chris$ ps -ef | grep dnsmasq > > > dnsmasq 933 1 0 Dec06 ? 00:00:22 /usr/sbin/dnsmasq -x > > > /run/dnsmasq/dnsmasq.pid > > -u dnsmasq -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service > > --trust-anchor=.,20326,8,2,e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d > > > > > > > chris 86541 3774 0 15:05 pts/1 00:00:00 grep > > > --color=auto dnsmasq > > > chris$ > > > > > > As can be seen dnsmasq is running and subsequent queries work without any > > > error (or delay). The above timeout is a few seconds, maybe five or a bit > > > less. > > > > > > There's no dnsmasq related error message in syslog (nothing for today at > > > all). The system homepi is a Raspberry Pi on the same LAN as the laptop > > > running dnsmasq, The error isn't only for one particular host, I've seen > > > it for other systems on my LAN. > > > > > > Can anyone suggest what might be causing the error and/or how to diagnose > > > what's wrong? > > > > > > > It looks like the first query (or its reply) was dropped, host retried, > > and it worked second time around. > > > > Since DNS transport is normally across UDP, which is defined as > > unreliable, this is completely normal. Except that the UDP packets are > > not actually traversing a network, they're going via the lo interface > > within one machine. I'm sure there are circumstances where UDP packets > > can get dropped in the kernel when going via the lo interface, but it > > shouldn't happen very often. Is the machine under heavy load or memory > > pressure? Maybe a network reconfiguration event could drop packets? > > > No, it's not a heavily loaded system by any means.
Acknowledge. > It's a Thinkpad T470 laptop with an I7 processor and is virtually > never worked hard at all. Just randomly running top now shows:- > > top - 09:59:28 up 12:04, 3 users, load average: 0.20, 0.12, 0.10 > Tasks: 254 total, 1 running, 253 sleeping, 0 stopped, 0 zombie > %Cpu(s): 1.5 us, 0.2 sy, 0.0 ni, 97.9 id, 0.3 wa, 0.0 hi, 0.0 si, > 0.0 st > MiB Mem : 7790.8 total, 296.7 free, 1032.4 used, 6461.8 > buff/cache > MiB Swap: 15258.0 total, 15255.5 free, 2.5 used. 6370.8 avail > Mem > > That's about the way it always is (three users are all me). > > What I don't understand is that there's nothing at all in the logs about the > failure/timeout. Imagination is more important as knowledge --Albert Einstein The sympthoms are that client request doesn't reach the server, hence the report of "time out". > Can I increase dnsmasq's logging to see if anything shows > up? It's just 'my' laptop so there isn't a lot of DNS. Add another DNS client for collecting more datapoints. So try to reproduce the issue with `dig` and/or `nslookup` whenever you encounter it with `host`. Groeten Geert Stappers P.S. Thanks for making it possible that we can read in the discussion order. -- Silence is hard to parse _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
