[Dnsmasq-discuss] Upgrade to [x]ubuntu 23.10 means dnsmasg can't read /run/NetworkManager
Up until now I have the following in my /etc/dnsmasq.conf:- resolv-file=/run/NetworkManager/no-stub-resolv.conf This means that dnsmasq uses the upstream DNS that Network Manager configures. When I'm on the local LAN this resolves to 'my' DNS server at 192.168.1.2, when I'm connected somewhere else Network Manager sorts things out accordingly and dnsmasq gets the right upstream DNS server. However the latest Ubuntu update has tightened the permissions on /etc/NetworkManager and dnsmasq can't read the file /run/NetworkManager/no-stub-resolv.conf. I know this is a slightly non-standard configuration but it has worked very nicely for me for some years. Can anyone suggest a way to fix this? Obviously /run/NetworkManager/no-stub-resolv.conf is created at every boot so the permissions will revert to 'too strict' every time I start the system. -- Chris Green ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] Occasional "communications error", how to diagnose?
On Thu, Dec 14, 2023 at 10:04:02AM +, Chris Green wrote: > On Wed, Dec 13, 2023 at 08:59:05PM +, 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 865413774 0 15:05 pts/100:00:00 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
Re: [Dnsmasq-discuss] Occasional "communications error", how to diagnose?
On Wed, Dec 13, 2023 at 08:59:05PM +, 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 865413774 0 15:05 pts/100:00:00 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. 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. 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. -- Chris Green ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
