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After upgrading to Ubuntu 24.04 I can't make any network connections, wired or wireless with automatic DHCP enabled. If I set IP Address, Netmask and Gateway manually everything works. To get the wireless connection to work I had to select the BSSID and MAC address of the wireless card under the Identity tab. I also needed to set a DNS Server address of 8.8.8.8 to browse the internet.

I have tried re-installing NetworkManager with no change. I have made the /etc/resolv.conf link to /run/NetworkManager/resolv.conf (it was linked to /run/systemd/resolve/stub-resolv.conf).

There seems to be a problem with NetworkManager as indicated below in the line:

● NetworkManager-wait-online.service loaded failed failed Network Manager Wait Online

Output of : systemctl --type=service

  UNIT                                                    LOAD   ACTIVE SUB     DESCRIPTION
  accounts-daemon.service                                 loaded active running Accounts Service
  alsa-restore.service                                    loaded active exited  Save/Restore Sound Card State
  apparmor.service                                        loaded active exited  Load AppArmor profiles
  apport.service                                          loaded active exited  automatic crash report generation
  binfmt-support.service                                  loaded active exited  Enable support for additional executable binary formats
  bluetooth.service                                       loaded active running Bluetooth service
  chrony.service                                          loaded active running chrony, an NTP client/server
  colord.service                                          loaded active running Manage, Install and Generate Color Profiles
  console-setup.service                                   loaded active exited  Set console font and keymap
  cron.service                                            loaded active running Regular background program processing daemon
  cups.service                                            loaded active running CUPS Scheduler
  dbus.service                                            loaded active running D-Bus System Message Bus
  finalrd.service                                         loaded active exited  Create final runtime dir for shutdown pivot root
  fwupd.service                                           loaded active running Firmware update daemon
  [email protected]                                      loaded active running Getty on tty1
  gnome-remote-desktop.service                            loaded active running GNOME Remote Desktop
  kerneloops.service                                      loaded active running Tool to automatically collect and submit kernel crash signatures
  keyboard-setup.service                                  loaded active exited  Set the console keyboard layout
  kmod-static-nodes.service                               loaded active exited  Create List of Static Device Nodes
  lightdm.service                                         loaded active running Light Display Manager
  lm-sensors.service                                      loaded active exited  Initialize hardware monitoring sensors
  ModemManager.service                                    loaded active running Modem Manager
  mono-xsp4.service                                       loaded active exited  LSB: Mono XSP4
  networkd-dispatcher.service                             loaded active running Dispatcher daemon for systemd-networkd
● NetworkManager-wait-online.service                      loaded failed failed  Network Manager Wait Online
  NetworkManager.service                                  loaded active running Network Manager
  openvpn.service                                         loaded active exited  OpenVPN service
  osspd.service                                           loaded active running OSS Proxy Daemon
  plymouth-quit-wait.service                              loaded active exited  Hold until boot process finishes up
  plymouth-read-write.service                             loaded active exited  Tell Plymouth To Write Out Runtime Data
  plymouth-start.service                                  loaded active exited  Show Plymouth Boot Screen
  polkit.service                                          loaded active running Authorization Manager
  power-profiles-daemon.service                           loaded active running Power Profiles daemon
  rsyslog.service                                         loaded active running System Logging Service
  rtirq.service                                           loaded active exited  LSB: Realtime IRQ thread tunning.
  rtkit-daemon.service                                    loaded active running RealtimeKit Scheduling Policy Service
  setvtrgb.service                                        loaded active exited  Set console scheme
  snap.cups.cups-browsed.service                          loaded active running Service for snap application cups.cups-browsed
  snap.cups.cupsd.service                                 loaded active running Service for snap application cups.cupsd
  snap.hplip-printer-app.hplip-printer-app-server.service loaded active running Service for snap application hplip-printer-app.hplip-printer-app-server
  snapd.apparmor.service                                  loaded active exited  Load AppArmor profiles managed internally by snapd
  snapd.seeded.service                                    loaded active exited  Wait until snapd is fully seeded
  snapd.service                                           loaded active running Snap Daemon
  switcheroo-control.service                              loaded active running Switcheroo Control Proxy service
  systemd-binfmt.service                                  loaded active exited  Set Up Additional Binary Formats
  systemd-fsck@dev-disk-by\x2duuid-E671\x2dBC55.service   loaded active exited  File System Check on /dev/disk/by-uuid/E671-BC55
  systemd-journal-flush.service                           loaded active exited  Flush Journal to Persistent Storage
  systemd-journald.service                                loaded active running Journal Service
  systemd-logind.service                                  loaded active running User Login Management
  systemd-modules-load.service                            loaded active exited  Load Kernel Modules
  systemd-oomd.service                                    loaded active running Userspace Out-Of-Memory (OOM) Killer
  systemd-random-seed.service                             loaded active exited  Load/Save OS Random Seed
  systemd-remount-fs.service                              loaded active exited  Remount Root and Kernel File Systems
  systemd-resolved.service                                loaded active running Network Name Resolution
  systemd-sysctl.service                                  loaded active exited  Apply Kernel Variables
  systemd-tmpfiles-setup-dev-early.service                loaded active exited  Create Static Device Nodes in /dev gracefully
  systemd-tmpfiles-setup-dev.service                      loaded active exited  Create Static Device Nodes in /dev
  systemd-tmpfiles-setup.service                          loaded active exited  Create Volatile Files and Directories
  systemd-udev-trigger.service                            loaded active exited  Coldplug All udev Devices
  systemd-udevd.service                                   loaded active running Rule-based Manager for Device Events and Files
  systemd-update-utmp.service                             loaded active exited  Record System Boot/Shutdown in UTMP
  systemd-user-sessions.service                           loaded active exited  Permit User Sessions
  thermald.service                                        loaded active running Thermal Daemon Service
  udisks2.service                                         loaded active running Disk Manager
  ufw.service                                             loaded active exited  Uncomplicated firewall
  unattended-upgrades.service                             loaded active running Unattended Upgrades Shutdown
  upower.service                                          loaded active running Daemon for power management
  [email protected]                           loaded active exited  User Runtime Directory /run/user/1000
  [email protected]                                       loaded active running User Manager for UID 1000
  wpa_supplicant.service                                  loaded active running WPA supplicant
  xrdp-sesman.service                                     loaded active running xrdp session manager
  xrdp.service                                            loaded active running xrdp daemon

Legend: LOAD   → Reflects whether the unit definition was properly loaded.
        ACTIVE → The high-level unit activation state, i.e. generalization of SUB.
        SUB    → The low-level unit activation state, values depend on unit type.

72 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

This is the output from dmesg for a failed connection:

[ 3420.257877] wlp4s0: authenticate with 0e:80:63:e5:36:31 (local address=74:19:f8:11:12:47)
[ 3420.257884] wlp4s0: send auth to 0e:80:63:e5:36:31 (try 1/3)
[ 3420.259915] wlp4s0: authenticated
[ 3420.260273] wlp4s0: associate with 0e:80:63:e5:36:31 (try 1/3)
[ 3420.264374] wlp4s0: RX AssocResp from 0e:80:63:e5:36:31 (capab=0x431 status=0 aid=1)
[ 3420.264699] wlp4s0: associated
[ 3420.391015] kauditd_printk_skb: 5 callbacks suppressed
[ 3420.391018] audit: type=1400 audit(1717407527.425:349): apparmor="DENIED" operation="exec" class="file" profile="/{,usr/}sbin/dhclient" name="/usr/libexec/nm-dhcp-helper" pid=10351 comm="dhclient" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
[ 3420.402616] audit: type=1400 audit(1717407527.437:350): apparmor="DENIED" operation="open" class="file" profile="/{,usr/}sbin/dhclient" name="/etc/hostid" pid=10342 comm="dhclient" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
[ 3420.553759] audit: type=1400 audit(1717407527.588:351): apparmor="DENIED" operation="exec" class="file" profile="/{,usr/}sbin/dhclient" name="/usr/libexec/nm-dhcp-helper" pid=10352 comm="dhclient" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
[ 3465.209497] wlp4s0: deauthenticating from 0e:80:63:e5:36:31 by local choice (Reason: 3=DEAUTH_LEAVING)
[ 3465.743373] wlp4s0: 80 MHz not supported, disabling VHT
[ 3465.744517] wlp4s0: authenticate with 0c:80:63:e5:36:31 (local address=74:19:f8:11:12:47)
[ 3465.744527] wlp4s0: send auth to 0c:80:63:e5:36:31 (try 1/3)
[ 3465.747055] wlp4s0: authenticated
[ 3465.747519] wlp4s0: associate with 0c:80:63:e5:36:31 (try 1/3)
[ 3465.751536] wlp4s0: RX AssocResp from 0c:80:63:e5:36:31 (capab=0x431 status=0 aid=2)
[ 3465.751875] wlp4s0: associated
[ 3475.753904] wlp4s0: deauthenticating from 0c:80:63:e5:36:31 by local choice (Reason: 3=DEAUTH_LEAVING)

There seems to be a problem with apparmor not having rights to access either dhclient or nm-dhcp-helper.

Any ideas gratefully received.

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  • pls also add which version of Ubuntu and if you are running desktop or server, also about your question refer to askubuntu.com/questions/1018576/…
    – amar
    Commented Jun 2 at 16:22
  • Problems ocurred after upgrade to ubuntu 24.04 as stated in my original question. Wifi is Realtek internal PCI card. Kernel drivers are loaded. When I select Automatic in the Wireless connection it doesn't connect. When I manually enter the IP address, netmask, DNS, etc it will connect.
    – garybarnes59
    Commented Jun 2 at 17:06

1 Answer 1

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The problem is being caused by apparmor. I have confirmed this by disabling the dhclient profile in /etc/apparmor.d/sbin.dhclient as follows:

cd /etc/apparmor.d

If there is no disable directory create it as follows:

sudo mkdir /etc/apparmor.d/disable

Create a link to the sbin.dhclient profile in the new disable directory:

sudo ln -s /etc/apparmor.d/sbin.dhclient /etc/apparmor.d/disable

The profile is currently loaded and so needs to be disabled:

sudo apparmor_parser -R /etc/apparmor.d/sbin.dhclient

Obviously this is not a permanent solution, and I know nothing about apparmor, so I will move this to a more specific question about apparmor and how to modify the profile so that dhclient works correctly when called by NetworkManager.

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