I've been bothered for a while that my laptop (which runs a local dnsmasq instance for caching) stops resolving names after returning from suspend, and sometimes spontaneously as well. Restarting dnsmasq would always fix this.
It finally started bothering me enough to debug it, and what I think happens is something like this: - Dnsmasq is configured to use the resolv.conf file maintained by systemd-resolved, the nameserver manager component of systemd-networkd. This file is updated whenever nameservers change from DHCP or configuration. - Sometimes, it seems, systemd-resolved rewrites this file twice within a fairly short time; once empty and again shortly after with the right nameservers. Dnsmasq only picks up the first rewrite: Oct 19 19:44:50 alrua-x1 dnsmasq[30391]: reading /etc/dnsmasq-resolv.conf Oct 19 19:44:50 alrua-x1 dnsmasq[30391]: ignoring nameserver 127.0.0.1 - local interface But subsequently touching the file makes dnsmasq pick up on the change and name resolution works again: Oct 19 19:49:30 alrua-x1 sudo[2104]: alrua : TTY=pts/4 ; PWD=/home/alrua ; USER=root ; COMMAND=/usr/bin/touch /run/systemd/resolve/resolv.conf Oct 19 19:49:30 alrua-x1 sudo[2104]: pam_unix(sudo:session): session opened for user root by (uid=0) Oct 19 19:49:30 alrua-x1 sudo[2104]: pam_unix(sudo:session): session closed for user root Oct 19 19:49:33 alrua-x1 dnsmasq[30391]: reading /etc/dnsmasq-resolv.conf Oct 19 19:49:33 alrua-x1 dnsmasq[30391]: ignoring nameserver 127.0.0.1 - local interface Oct 19 19:49:33 alrua-x1 dnsmasq[30391]: using nameserver 10.61.32.1#53 Oct 19 19:49:33 alrua-x1 dnsmasq[30391]: using nameserver 1.1.1.1#53 Oddly enough, when first connecting to a network, there's a delay between the two writes of the resolv-file, which means things work: Oct 19 20:05:59 alrua-x1 systemd-networkd[960]: wlan0 : gained carrier Oct 19 20:05:59 alrua-x1 systemd-networkd[960]: wlan0 : DHCPv4 address 10.71.0.250/20 via 10.71.0.1 Oct 19 20:05:59 alrua-x1 dnsmasq[22661]: reading /etc/dnsmasq-resolv.conf Oct 19 20:05:59 alrua-x1 dnsmasq[22661]: ignoring nameserver 127.0.0.1 - local interface Oct 19 20:06:03 alrua-x1 dnsmasq[22661]: reading /etc/dnsmasq-resolv.conf Oct 19 20:06:03 alrua-x1 dnsmasq[22661]: ignoring nameserver 127.0.0.1 - local interface Oct 19 20:06:03 alrua-x1 dnsmasq[22661]: using nameserver 10.61.32.1#53 Oct 19 20:06:03 alrua-x1 dnsmasq[22661]: using nameserver 1.1.1.1#53 Either way, fixing dnsmasq to always notice the updated files would be desirable. Not sure if the recently posted nanosecond resolution patch is the way to go about it, but consider this a motivation to do *something* :) -Toke _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
