Problem:
Running Ubuntu 17.10
I have been trying to resolv (hehe) this issue for about a week now and despite countless Google searches and about 20 different attempts, I can not stop dnsmasq from periodically causing my CPU to spike for about a minute with the following offenders:
systemd-resolvedsystemd-journalddnsmasq
Monitoring journalctl -f I see this every time it happens:
maximum number of concurrent dns queries reached (150)
Accompanied/preceded by a crazy loop of requests to some domain (usually ubuntu connection check) like the following:
query[A] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.1.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
query[A] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
query[AAAA] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
query[AAAA] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
query[A] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
query[AAAA] connectivity-check.ubuntu.com from 127.0.0.1
forwarded connectivity-check.ubuntu.com to 127.0.0.53
I've found that changing my /etc/resolv.conf to use nameserver 127.0.0.53 causes the spike to dissipate almost instantaneously.
However, as that file is updated regularly by Network Manager, I have to do this about once an hour.
Configuration:
/etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.1
search fios-router.home
/etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile
[ifupdown]
managed=false
[device]
wifi.scan-rand-mac-address=no
/etc/dnsmasq.conf
// All default except this at the very end for my wildcard DNS
address=/asmar.d/127.0.0.1
/run/dnsmasq/resolv.conf
nameserver 127.0.0.53
/run/resolvconf/interfaces:
lo.dnsmasq:
nameserver 127.0.0.1
systemd-resolved:
nameserver 127.0.0.53
/etc/resolvconf/interface-order:
# interface-order(5)
lo.inet6
lo.inet
lo.@(dnsmasq|pdnsd)
lo.!(pdns|pdns-recursor)
lo
tun*
tap*
hso*
em+([0-9])?(_+([0-9]))*
p+([0-9])p+([0-9])?(_+([0-9]))*
@(br|eth)*([^.]).inet6
@(br|eth)*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc)
@(br|eth)*([^.]).inet
@(br|eth)*([^.]).@(dhclient|dhcpcd|pump|udhcpc)
@(br|eth)*
@(ath|wifi|wlan)*([^.]).inet6
@(ath|wifi|wlan)*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc)
@(ath|wifi|wlan)*([^.]).inet
@(ath|wifi|wlan)*([^.]).@(dhclient|dhcpcd|pump|udhcpc)
@(ath|wifi|wlan)*
ppp*
*
systemd-resolve --status:
Global
DNS Servers: 127.0.0.1
DNSSEC NTA: 10.in-addr.arpa
16.172.in-addr.arpa
168.192.in-addr.arpa
17.172.in-addr.arpa
18.172.in-addr.arpa
19.172.in-addr.arpa
20.172.in-addr.arpa
21.172.in-addr.arpa
22.172.in-addr.arpa
23.172.in-addr.arpa
24.172.in-addr.arpa
25.172.in-addr.arpa
26.172.in-addr.arpa
27.172.in-addr.arpa
28.172.in-addr.arpa
29.172.in-addr.arpa
30.172.in-addr.arpa
31.172.in-addr.arpa
corp
d.f.ip6.arpa
home
internal
intranet
lan
local
private
test
Link 5 (br-b1f5461ac410)
Current Scopes: none
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
Link 4 (docker0)
Current Scopes: none
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
Link 3 (wlp62s0)
Current Scopes: none
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
Link 2 (enp61s0)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
DNS Servers: 8.8.8.8
8.8.4.4
::1
Questions:
How can I resolve this issue while still using my wildcard domain name?
Optional: How can I achieve this while using Google DNS?
Please do not recommend upping the concurrent dns queries. That is not a solution.
