The following kern.log is a record of the kernel events. Please note that I used the widget to close the Ethernet connection, and note subsequent issues. Also note that the WiFi connection has a lease time for a nailed up connection IP address (??)

dad@dad314159:/var/log$ tail kern.log -n 100
Sep 21 10:53:51 dad314159 sddm[3332]: Session "/usr/share/xsessions/plasma.desktop" selected, command: "/usr/bin/startkde"
Sep 21 10:53:51 dad314159 sddm[3332]: Adding cookie to "/var/run/sddm/{cfd8e347-ff7a-40eb-936b-7b97cbf4a408}"
Sep 21 10:53:51 dad314159 sddm-helper[3622]: [PAM] Starting...
Sep 21 10:53:51 dad314159 sddm-helper[3622]: [PAM] Authenticating...
Sep 21 10:53:51 dad314159 sddm-helper[3622]: [PAM] returning.
Sep 21 10:53:51 dad314159 sddm[3332]: Authenticated successfully
Sep 21 10:53:51 dad314159 sddm-helper[3622]: Starting: "/etc/sddm/Xsession" "/usr/bin/startkde"
Sep 21 10:53:51 dad314159 sddm-helper[3694]: Adding cookie to "/home/dad/.Xauthority"
Sep 21 10:53:51 dad314159 sddm[3332]: Session started
Sep 21 10:53:51 dad314159 kernel: [   11.697101] audit: type=1400 audit(1506005631.852:30): apparmor="DENIED" operation="capable" profile="/usr/sbin/cupsd" pid=3747 comm="usb" capability=35  capname="wake_alarm"
Sep 21 10:53:51 dad314159 kernel: [   11.702854] usblp0: removed
Sep 21 10:53:51 dad314159 kernel: [   11.718373] usblp 2-2.2:1.1: usblp0: USB Bidirectional printer dev 7 if 1 alt 0 proto 2 vid 0x04B8 pid 0x1106
Sep 21 10:53:56 dad314159 NetworkManager[956]: <info>  [1506005636.1609] manager: WiFi hardware radio set enabled
Sep 21 10:53:56 dad314159 NetworkManager[956]: <info>  [1506005636.1610] manager: WWAN hardware radio set enabled
Sep 21 10:53:56 dad314159 kernel: [   16.467172] audit: type=1400 audit(1506005636.620:31): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/proc/4030/status" pid=4030 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
Sep 21 10:53:56 dad314159 kernel: [   16.467176] audit: type=1400 audit(1506005636.620:32): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4030 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Sep 21 10:53:56 dad314159 kernel: [   16.467178] audit: type=1400 audit(1506005636.620:33): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/proc/4030/status" pid=4030 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
Sep 21 10:53:56 dad314159 kernel: [   16.495191] audit: type=1400 audit(1506005636.648:34): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/etc/mysql/my.cnf.fallback" pid=4030 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Sep 21 10:53:56 dad314159 kernel: [   16.521493] audit: type=1400 audit(1506005636.676:35): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/proc/4031/status" pid=4031 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
Sep 21 10:53:56 dad314159 kernel: [   16.524452] audit: type=1400 audit(1506005636.680:36): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/sys/devices/system/node/" pid=4031 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
Sep 21 10:53:56 dad314159 kernel: [   16.524699] audit: type=1400 audit(1506005636.680:37): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld-akonadi///usr/sbin/mysqld" name="/proc/4031/status" pid=4031 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
Sep 21 10:53:58 dad314159 NetworkManager[956]: <warn>  [1506005638.1598] device (wlp12s0): re-acquiring supplicant interface (#1).
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.1983] device (wlp12s0): supplicant interface state: starting -> ready
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.1984] device (wlp12s0): state change: unavailable -> disconnected (reason 'supplicant-available') [20 30 42]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.7826] device (wlp12s0): supplicant interface state: ready -> inactive
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8650] policy: auto-activating connection 'Disco'
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8708] device (wlp12s0): Activation: starting connection 'Disco' (facc7167-12ef-42d2-a39f-35aaf8a261f5)
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8910] device (wlp12s0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8937] device (wlp12s0): state change: prepare -> config (reason 'none') [40 50 0]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8958] device (wlp12s0): Activation: (wifi) access point 'Disco' has security, but secrets are required.
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.8964] device (wlp12s0): state change: config -> need-auth (reason 'none') [50 60 0]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9454] device (wlp12s0): state change: need-auth -> prepare (reason 'none') [60 40 0]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9561] device (wlp12s0): state change: prepare -> config (reason 'none') [40 50 0]
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9585] device (wlp12s0): Activation: (wifi) connection 'Disco' has security, and secrets exist.  No new secrets needed.
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9595] Config: added 'ssid' value 'Disco'
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9601] Config: added 'scan_ssid' value '1'
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9607] Config: added 'key_mgmt' value 'WPA-PSK'
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9613] Config: added 'psk' value '<omitted>'
Sep 21 10:53:58 dad314159 NetworkManager[956]: <info>  [1506005638.9695] sup-iface[0xfae380,wlp12s0]: config: set interface ap_scan to 1
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.3775] device (wlp12s0): supplicant interface state: inactive -> associating
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4127] device (wlp12s0): supplicant interface state: associating -> associated
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4271] device (wlp12s0): supplicant interface state: associated -> 4-way handshake
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4279] device (wlp12s0): supplicant interface state: 4-way handshake -> completed
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4285] device (wlp12s0): Activation: (wifi) Stage 2 of 5 (Device Configure) successful.  Connected to wireless network 'Disco'.
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4336] device (wlp12s0): state change: config -> ip-config (reason 'none') [50 70 0]
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4378] dhcp4 (wlp12s0): activation: beginning transaction (timeout in 45 seconds)
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.4515] dhcp4 (wlp12s0): dhclient started with pid 4137
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5403]   address 192.168.99.11
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5409]   plen 24 (255.255.255.0)
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5415]   gateway 192.168.99.1
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5421]   server identifier 192.168.99.1
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5427]   lease time 86400
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5433]   hostname 'dad314159'
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5438]   nameserver '192.168.99.1'
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5444]   nameserver '192.168.99.1'
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5449]   domain name 'Disco'
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5455]   wins '192.168.99.1'
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5461] dhcp4 (wlp12s0): state changed unknown -> bound
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5603] device (wlp12s0): state change: ip-config -> ip-check (reason 'none') [70 80 0]
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.5896] device (wlp12s0): state change: ip-check -> secondaries (reason 'none') [80 90 0]
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.6081] device (wlp12s0): state change: secondaries -> activated (reason 'none') [90 100 0]
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.6942] dns-plugin[0xf3b4e0]: starting dnsmasq...
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.7105] dns-mgr: Writing DNS information to /sbin/resolvconf
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.8699] device (wlp12s0): Activation: successful, device activated.
Sep 21 10:53:59 dad314159 NetworkManager[956]: <info>  [1506005639.9104] dnsmasq[0xf3b4e0]: dnsmasq appeared as :1.48
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.0918] dhcp6 (wlp12s0): activation: beginning transaction (timeout in 45 seconds)
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.1028] dhcp6 (wlp12s0): dhclient started with pid 4286
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.1058] policy: set 'Disco' (wlp12s0) as default for IPv6 routing and DNS
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.1061] dns-mgr: Writing DNS information to /sbin/resolvconf
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.4069]   nameserver '2001:558:feed::1'
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.4076]   nameserver '2001:558:feed::2'
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.4082] dhcp6 (wlp12s0): state changed unknown -> bound
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.4288] dhcp6 (wlp12s0): client pid 4286 exited with status 0
Sep 21 10:54:02 dad314159 NetworkManager[956]: <info>  [1506005642.4288] dhcp6 (wlp12s0): state changed bound -> done
Sep 21 10:54:14 dad314159 kernel: [   34.336410] vboxdrv: Found 2 processor cores
Sep 21 10:54:14 dad314159 kernel: [   34.362216] vboxdrv: fAsync=0 offMin=0x1b9 offMax=0x853
Sep 21 10:54:14 dad314159 kernel: [   34.468429] vboxdrv: TSC mode is Synchronous, tentative frequency 2094749562 Hz
Sep 21 10:54:14 dad314159 kernel: [   34.468431] vboxdrv: Successfully loaded version 5.0.40_Ubuntu (interface 0x00240000)
Sep 21 10:54:14 dad314159 kernel: [   34.746754] VBoxNetFlt: Successfully started.
Sep 21 10:54:14 dad314159 kernel: [   34.797564] VBoxNetAdp: Successfully started.
Sep 21 10:54:14 dad314159 kernel: [   34.828415] VBoxPciLinuxInit
Sep 21 10:54:15 dad314159 kernel: [   34.846267] vboxpci: IOMMU not found (not registered)
Sep 21 10:56:28 dad314159 NetworkManager[956]: <info>  [1506005788.8782] device (enp9s0): state change: activated -> deactivating (reason 'user-requested') [100 110 39]
Sep 21 10:56:28 dad314159 NetworkManager[956]: <info>  [1506005788.8966] audit: op="device-disconnect" interface="enp9s0" ifindex=2 pid=3891 uid=1000 result="success"
Sep 21 10:56:28 dad314159 NetworkManager[956]: <info>  [1506005788.8976] device (enp9s0): state change: deactivating -> disconnected (reason 'user-requested') [110 30 39]
Sep 21 10:56:28 dad314159 kernel: [  169.106997] IPv6: ADDRCONF(NETDEV_UP): enp9s0: link is not ready
Sep 21 10:56:28 dad314159 NetworkManager[956]: <info>  [1506005788.9035] policy: set 'Disco' (wlp12s0) as default for IPv4 routing and DNS
Sep 21 10:56:51 dad314159 kernel: [  191.816129] perf: interrupt took too long (2538 > 2500), lowering kernel.perf_event_max_sample_rate to 78750
Sep 21 10:57:48 dad314159 kernel: [  248.408358] perf: interrupt took too long (3186 > 3172), lowering kernel.perf_event_max_sample_rate to 62750
Sep 21 10:59:23 dad314159 kernel: [  343.342486] perf: interrupt took too long (3986 > 3982), lowering kernel.perf_event_max_sample_rate to 50000
Sep 21 11:06:51 dad314159 pulseaudio[7009]: Failed to find a working profile.
Sep 21 11:06:51 dad314159 pulseaudio[7009]: Failed to load module "module-alsa-card" (argument: "device_id="1" name="usb-M-Audio_USB_Uno_MIDI_Interface-00" card_name="alsa_card.usb-M-Audio_USB_Uno_MIDI_Interface-00" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Sep 21 11:07:17 dad314159 pulseaudio[7009]: GetManagedObjects() failed: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Sep 21 11:14:01 dad314159 kernel: [ 1222.058690] perf: interrupt took too long (4992 > 4982), lowering kernel.perf_event_max_sample_rate to 40000
Sep 21 12:03:22 dad314159 kernel: [ 4183.060322] ERROR @wl_dev_intvar_get : 
Sep 21 12:03:22 dad314159 kernel: [ 4183.060325] error (-1)
Sep 21 12:03:22 dad314159 kernel: [ 4183.060331] ERROR @wl_cfg80211_get_tx_power : 
Sep 21 12:03:22 dad314159 kernel: [ 4183.060332] error (-1)
Sep 21 12:04:39 dad314159 kernel: [ 4259.883813] apport-kde[10439]: segfault at 7f86e447ab00 ip 00007f870faef805 sp 00007ffc3181a8a8 error 4 in QtCore.cpython-35m-x86_64-linux-gnu.so[7f870f905000+26b000]
Sep 21 12:40:01 dad314159 kernel: [ 6381.666160] sky2 0000:09:00.0 enp9s0: disabling interface
dad@dad314159:/var/log$