Note that on my machine (clean 16.10 install, upgraded to 17.04 and later 17.10), DNS resolution already partially broke in 17.04 (involving the switch to systemd-resolve). With Ubuntu 17.04, DNS resolution was broken after suspending, moving to a different WiFi, and resuming the machine. This could be manually fixed by manually running dhclient. This does not fix the abovementioned issue, though.
** Description changed: Since upgrading to 17.10, hostname resolution (via, e.g., Firefox or the "host" command-line tool) does not work reliably anymore. Once hostname resolution fails (Firefox 57: "Hmm. We're having trouble finding that site."), manually resolving the host via "systemd-resolve" succeeds and temporarily allows Firefox to also resolve that host. After a few minutes, resolution of the same host fails again. Example with command-line "host" utility: $ host www.heise.de ;; connection timed out; no servers could be reached - $ cat /etc/resolv.conf + $ cat /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 127.0.0.53 search fritz.box $ systemd-resolve www.heise.de www.heise.de: 2a02:2e0:3fe:1001:7777:772e:2:85 - 193.99.144.85 + 193.99.144.85 -- Information acquired via protocol DNS in 273.2ms. -- Data is authenticated: no $ host www.heise.de www.heise.de has address 193.99.144.85 www.heise.de has IPv6 address 2a02:2e0:3fe:1001:7777:772e:2:85 + $ systemd-resolve --status Global - DNS Servers: 192.168.178.1 - DNS Domain: fritz.box - 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 + DNS Servers: 192.168.178.1 + DNS Domain: fritz.box + 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 4 (wlp3s0) - Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6 - LLMNR setting: yes + Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6 + LLMNR setting: yes MulticastDNS setting: no - DNSSEC setting: no - DNSSEC supported: no - DNS Servers: fd00::cece:1eff:fe61:2ece + DNSSEC setting: no + DNSSEC supported: no + DNS Servers: fd00::cece:1eff:fe61:2ece Link 3 (enp0s20f0u5c2) - Current Scopes: none - LLMNR setting: yes + Current Scopes: none + LLMNR setting: yes MulticastDNS setting: no - DNSSEC setting: no - DNSSEC supported: no + DNSSEC setting: no + DNSSEC supported: no Link 2 (enp0s31f6) - Current Scopes: none - LLMNR setting: yes + Current Scopes: none + LLMNR setting: yes MulticastDNS setting: no - DNSSEC setting: no - DNSSEC supported: no + DNSSEC setting: no + DNSSEC supported: no [... wait 2-3 minutes ...] $ host www.heise.de ;; connection timed out; no servers could be reached $ systemd-resolve www.heise.de www.heise.de: 2a02:2e0:3fe:1001:7777:772e:2:85 - 193.99.144.85 + 193.99.144.85 -- Information acquired via protocol DNS in 284.2ms. -- Data is authenticated: no $ host www.heise.de www.heise.de has address 193.99.144.85 www.heise.de has IPv6 address 2a02:2e0:3fe:1001:7777:772e:2:85 ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: systemd 234-2ubuntu12.1 ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4 Uname: Linux 4.13.0-16-generic x86_64 ApportVersion: 2.20.7-0ubuntu3.4 Architecture: amd64 CurrentDesktop: KDE Date: Sat Nov 18 19:32:56 2017 InstallationDate: Installed on 2016-11-26 (357 days ago) InstallationMedia: Kubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.1) MachineType: LENOVO 20FXS05500 ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.13.0-16-generic root=/dev/mapper/vgubuntu-root ro kopt=root=/dev/mapper/vgubuntu-root SourcePackage: systemd UpgradeStatus: Upgraded to artful on 2017-10-21 (28 days ago) dmi.bios.date: 09/04/2017 dmi.bios.vendor: LENOVO dmi.bios.version: R07ET79W (2.19 ) dmi.board.asset.tag: Not Available dmi.board.name: 20FXS05500 dmi.board.vendor: LENOVO dmi.board.version: Not Defined dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrR07ET79W(2.19):bd09/04/2017:svnLENOVO:pn20FXS05500:pvrThinkPadT460p:rvnLENOVO:rn20FXS05500:rvrNotDefined:cvnLENOVO:ct10:cvrNone: dmi.product.family: ThinkPad T460p dmi.product.name: 20FXS05500 dmi.product.version: ThinkPad T460p dmi.sys.vendor: LENOVO -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1733103 Title: DNS hostname resolution fails intermittently To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1733103/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
