[Bug 1727566] Re: extra left-behind domains break domain name rsolution

Fri Jan 26 19:29:41 UTC 2018

Thank you for reporting this bug and helping to improve Ubuntu.

Why do you believe that the problem here is one of 'leftover state'?
The systemd-resolve --status output shows a simple config, with a domain
search list and two DNS servers (one ipv4 address, one ipv6 address).
If some of this state is "leftover", it's not clear what state that is.

Are 10.1.0.1 and fda0:5173:b519::1 the correct DNS servers for your home
wifi?  Do these DNS lookups work correctly when you issue them directly
against the configured nameservers? (nslookup webvpn.purestorage.com
10.1.0.1; nslookup webvpn.purestorage.com fda0:5173:b519::1)  What
happens if you try to do the lookup with 'nslookup
webvpn.purestorage.com' instead of with systemd-resolve? (systemd-
resolve uses a different protocol to talk to systemd-resolved, and may
give different results - which normally indicates a bug.)

Can you provide a network trace of the DNS traffic when these lookups
fail?

** Changed in: systemd (Ubuntu)
       Status: Confirmed => Incomplete

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https://bugs.launchpad.net/bugs/1727566

Title:
  extra left-behind domains break domain name rsolution

Status in systemd package in Ubuntu:
  Incomplete

Bug description:
  This seems related to LP: #1717995 but that is marked fixed.

  I used my laptop at work, where I have a docking station with USB
  ethernet included (interface enx0050b6cf4d4a).  The dhcp on the wired
  ethernet includes my work domain, purestorage.com.  I undocked,
  suspended, and came home, where I have no USB ethernet (just wifi
  wlp4s0), and dhcp on wifi doesn't mention purestorage.com.  However, I
  still have leftover state that stops purestorage.com names from
  resolving:

  $ systemd-resolve webvpn.purestorage.com
  webvpn.purestorage.com: resolve call failed: No appropriate name servers or networks for name found

  $ 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 lan purestorage.com dev.purestorage.com

  $ systemd-resolve --status
  Global
            DNS Domain: lan
                        purestorage.com
                        dev.purestorage.com
            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 3 (wlp4s0)
        Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
         LLMNR setting: yes
  MulticastDNS setting: no
        DNSSEC setting: no
      DNSSEC supported: no
           DNS Servers: 10.1.0.1
                        fda0:5173:b519::1
            DNS Domain: lan

  Link 2 (enp0s31f6)
        Current Scopes: none
         LLMNR setting: yes
  MulticastDNS setting: no
        DNSSEC setting: no
      DNSSEC supported: no

  It seems there are still issues around network interfaces being
  removed but leaving behind their DNS config.

  ProblemType: Bug
  DistroRelease: Ubuntu 17.10
  Package: systemd 234-2ubuntu12
  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
  Architecture: amd64
  CurrentDesktop: ubuntu:GNOME
  Date: Wed Oct 25 17:48:47 2017
  InstallationDate: Installed on 2016-09-01 (419 days ago)
  InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Alpha amd64 (20160901)
  Lsusb:
   Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
   Bus 001 Device 004: ID 138a:0090 Validity Sensors, Inc. 
   Bus 001 Device 003: ID 13d3:5248 IMC Networks 
   Bus 001 Device 005: ID 056a:5087 Wacom Co., Ltd 
   Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  MachineType: LENOVO 20FRS2FK00
  ProcEnviron:
   TERM=screen
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-16-generic root=UUID=30d5ada5-835d-4cf7-96cf-3329c0316107 ro quiet splash vt.handoff=7
  SourcePackage: systemd
  UpgradeStatus: Upgraded to artful on 2017-07-26 (91 days ago)
  dmi.bios.date: 07/13/2017
  dmi.bios.vendor: LENOVO
  dmi.bios.version: N1FET53W (1.27 )
  dmi.board.asset.tag: Not Available
  dmi.board.name: 20FRS2FK00
  dmi.board.vendor: LENOVO
  dmi.board.version: SDK0J40697 WIN
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 31
  dmi.chassis.vendor: LENOVO
  dmi.chassis.version: None
  dmi.modalias: dmi:bvnLENOVO:bvrN1FET53W(1.27):bd07/13/2017:svnLENOVO:pn20FRS2FK00:pvrThinkPadX1Yoga1st:rvnLENOVO:rn20FRS2FK00:rvrSDK0J40697WIN:cvnLENOVO:ct31:cvrNone:
  dmi.product.family: ThinkPad X1 Yoga 1st
  dmi.product.name: 20FRS2FK00
  dmi.product.version: ThinkPad X1 Yoga 1st
  dmi.sys.vendor: LENOVO

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