1. top PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 19147 systemd+ 20 0 50848 6232 4572 R 99.0 0.1 5:43.81 systemd-resolve 1472 dnsmasq 20 0 57020 3084 2620 R 63.1 0.0 44:03.49 dnsmasq 2. journalctl -u systemd-resolved.service Apr 16 13:01:59 Danny systemd-resolved[19147]: DNSSEC validation failed for question clients-china.l.google.com IN A: failed-auxiliary Apr 16 13:02:02 Danny systemd-resolved[19147]: Using degraded feature set (UDP+EDNS0) for DNS server 127.0.0.1. Apr 16 13:02:08 Danny systemd-resolved[19147]: Server 127.0.0.1 does not support DNSSEC, downgrading to non-DNSSEC mode. Apr 16 13:06:24 Danny systemd-resolved[19147]: Server 192.168.128.1 does not support DNSSEC, downgrading to non-DNSSEC mode. Apr 16 13:11:24 Danny systemd-resolved[19147]: Grace period over, resuming full feature set (UDP+EDNS0+DO+LARGE) for DNS server 127.0.0.1. 3. journalctl -u dnsmasq.service Apr 16 13:18:27 Danny dnsmasq[1472]: Maximum number of concurrent DNS queries reached (max: 150) Apr 16 13:18:33 Danny dnsmasq[1472]: Maximum number of concurrent DNS queries reached (max: 150) Apr 16 13:18:39 Danny dnsmasq[1472]: Maximum number of concurrent DNS queries reached (max: 150) Apr 16 13:18:45 Danny dnsmasq[1472]: Maximum number of concurrent DNS queries reached (max: 150) Apr 16 13:18:51 Danny dnsmasq[1472]: Maximum number of concurrent DNS queries reached (max: 150) 4. lsb_release -a Distributor ID: Ubuntu Description: Ubuntu 17.04 Release: 17.04 Codename: zesty 5. sudo strace -p 1472 --- dnsmasq bind(12, {sa_family=AF_INET, sin_port=htons(37051), sin_addr=inet_addr("0.0.0.0")}, 16) = 0 sendto(12, "g\325\1\20\0\1\0\0\0\0\0\1\rclients-china\1l\6goo"..., 55, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, 16) = 55 poll([{fd=3, events=POLLIN}, {fd=4, events=POLLIN}, {fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=8, events=POLLIN}, {fd=9, events=POLLIN}, {fd=12, events=POLLIN}], 8, -1) = 2 ([{fd=4, revents=POLLIN}, {fd=12, revents=POLLIN}]) recvfrom(12, "g\325\201\200\0\1\0\6\0\0\0\1\rclients-china\1l\6goo"..., 5131, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.53")}, [16]) = 151 sendmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(33355), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\272\303\201\220\0\1\0\6\0\0\0\1\rclients-china\1l\6goo"..., 151}], msg_controllen=0, msg_flags=0}, 0) = 151 close(12) = 0 recvmsg(4, {msg_name(16)={sa_family=AF_INET, sin_port=htons(57326), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"C\21\1\20\0\1\0\0\0\0\0\1\rclients-china\1l\6goo"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 55 socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 12 fcntl(12, F_GETFL) = 0x2 (flags O_RDWR) fcntl(12, F_SETFL, O_RDWR|O_NONBLOCK) = 0 6. sudo strace -p 1914 clock_gettime(CLOCK_BOOTTIME, {5858, 172230641}) = 0 open("/run/systemd/netif/links/2", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory) stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=303, ...}) = 0 stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=303, ...}) = 0 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 18 connect(18, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 16) = 0 epoll_ctl(4, EPOLL_CTL_ADD, 18, {EPOLLIN, {u32=1040890848, u64=94559040879584}}) = 0 write(18, ";q\1\20\0\1\0\0\0\0\0\1\17ec2-52-7-217-10\tcom"..., 68) = 68 clock_gettime(CLOCK_BOOTTIME, {5858, 172456596}) = 0 clock_gettime(CLOCK_BOOTTIME, {5858, 172482649}) = 0 epoll_ctl(4, EPOLL_CTL_DEL, 18, NULL) = 0 close(18) = 0 sendmsg(15, {msg_name(16)={sa_family=AF_INET, sin_port=htons(45041), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"qX\201\200\0\1\0\1\0\0\0\1\17ec2-52-7-217-10\tcom"..., 84}], msg_controllen=28, [{cmsg_len=28, cmsg_level=SOL_IP, cmsg_type=IP_PKTINFO, {ipi_ifindex=if_nametoindex("lo"), ipi_spec_dst=inet_addr("127.0.0.53"), ipi_addr=inet_addr("127.0.0.53")}}], msg_flags=0}, 0) = 84 epoll_wait(4, [{EPOLLIN, {u32=1039855040, u64=94559039843776}}], 16, -1) = 1 clock_gettime(CLOCK_BOOTTIME, {5858, 172675790}) = 0 recvfrom(15, NULL, 0, MSG_PEEK|MSG_TRUNC, NULL, NULL) = 68 recvmsg(15, {msg_name(16)={sa_family=AF_INET, sin_port=htons(48677), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)=[{"\313{\1\20\0\1\0\0\0\0\0\1\17ec2-52-7-217-10\tcom"..., 3936}], msg_controllen=56, [{cmsg_len=28, cmsg_level=SOL_IP, cmsg_type=IP_PKTINFO, {ipi_ifindex=if_nametoindex("lo"), ipi_spec_dst=inet_addr("127.0.0.53"), ipi_addr=inet_addr("127.0.0.53")}}, {cmsg_len=20, cmsg_level=SOL_IP, cmsg_type=IP_TTL, {ttl=64}}], msg_flags=0}, 0) = 68 stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=303, ...}) = 0 getrandom("\213\235", 2, GRND_NONBLOCK) = 2 stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=303, ...}) = 0 getrandom(" \317", 2, GRND_NONBLOCK) = 2 7. 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 2 (wlan0) Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6 LLMNR setting: yes MulticastDNS setting: no DNSSEC setting: allow-downgrade DNSSEC supported: no DNS Servers: 192.168.128.1 DNS Domain: lan