昨日、暇を見つけてようやく16.04から18.04LTSにアップグレードしたところ、有線でのネットワーク接続ができなくなりました。
18.04にはFirefoxとFalkonがインストールされていますが、どちらもサイトを表示できないようです。

パソコンはDellのInspirom 530。概要は下記のとおりです。

OS：Ubuntu18.04LTS 32bit
メモリ：3.9GiB
プロセッサ：Intel Core 2 Duo CPU E6850 @3.00GHz x 2
グラフィック：GeForce 8600 GT/PCle/SSE2
GNOME:3.28.2

なお、同じパソコンにはLinux Mintもインストールしており、こちらは今のところ問題なくネットに接続できています。

次に、問題を解決するために、私が行った事柄を紹介します。
まず、NICを再確認しました。下記のとおり、Intel製のようです。

****@Inspiron-530:~$ lspci | grep Ethernet
00:19.0 Ethernet controller: Intel Corporation 82562V-2 10/100 Network Connection (rev 02)

次に、別のパソコンであれこれ検索して、Intel製のドライバe1000eの最新版をインストールしました。
インストールする際、チェックサムの確認を行わないよう設定しています。
ドライバをインストールした後の状態は下記のとおりです。

****@Inspiron-530:~$ modinfo e1000e
filename:       /lib/modules/4.15.0-39-generic/updates/drivers/net/ethernet/intel/e1000e/e1000e.ko
version:        3.4.2.1-NAPI
license:        GPL
description:    Intel(R) PRO/1000 Network Driver
author:         Intel Corporation, <[email protected]>
srcversion:     50B8562DBBE3F3EED222B57
alias:          pci:v00008086d000015BCsv*sd*bc*sc*i*
（中略）
alias:          pci:v00008086d0000105Esv*sd*bc*sc*i*
depends:        ptp
retpoline:      Y
name:           e1000e
vermagic:       4.15.0-39-generic SMP mod_unload 686
parm:           copybreak:Maximum size of packet that is copied to a new buffer on receive (uint)
parm:           TxIntDelay:Transmit Interrupt Delay (array of int)
parm:           TxAbsIntDelay:Transmit Absolute Interrupt Delay (array of int)
parm:           RxIntDelay:Receive Interrupt Delay (array of int)
parm:           RxAbsIntDelay:Receive Absolute Interrupt Delay (array of int)
parm:           InterruptThrottleRate:Interrupt Throttling Rate (array of int)
parm:           IntMode:Interrupt Mode (array of int)
parm:           SmartPowerDownEnable:Enable PHY smart power down (array of int)
parm:           KumeranLockLoss:Enable Kumeran lock loss workaround (array of int)
parm:           CrcStripping:Enable CRC Stripping, disable if your BMC needs the CRC (array of int)
parm:           EEE:Enable/disable on parts that support the feature (array of int)
parm:           Node:[ROUTING] Node to allocate memory on, default -1 (array of int)
parm:           debug:Debug level (0=none,...,16=all) (int)

ドライバをインストールすると解決するかと思ったのですが、全く改善されません。
原因を突き止めたくてログを見ても、私には理解できず、現時点ではこれが精いっぱいです。
何かよい知恵があれば、どうかお授けください。よろしくお願いいたします。

****@Inspiron-530:~$ zegrep e1000e /var/log/kern.log*
/var/log/kern.log:Dec  2 07:51:04 Inspiron-530 kernel: [  920.032094] e1000e: eth0 NIC Link is Down
/var/log/kern.log:Dec  2 07:51:13 Inspiron-530 kernel: [  929.352724] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log:Dec  2 07:51:13 Inspiron-530 kernel: [  929.352730] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.209908] e1000e: loading out-of-tree module taints kernel.
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.210072] e1000e: module verification failed: signature and/or required key missing - tainting kernel
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.210783] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.210784] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.210960] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.402175] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.402178] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log:Dec  2 11:35:55 Inspiron-530 kernel: [   33.402199] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log:Dec  2 11:36:02 Inspiron-530 kernel: [   43.588774] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log:Dec  2 11:36:02 Inspiron-530 kernel: [   43.588780] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.001204] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.001206] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.001362] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.188107] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.188111] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 11:05:57 Inspiron-530 kernel: [   13.188133] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 11:06:05 Inspiron-530 kernel: [   48.800776] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 11:06:05 Inspiron-530 kernel: [   48.800784] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    1.951975] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    1.951978] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    1.956287] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    2.128263] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    2.128267] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 11:39:40 Inspiron-530 kernel: [    2.128289] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 11:39:50 Inspiron-530 kernel: [   31.312769] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 11:39:50 Inspiron-530 kernel: [   31.312776] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.178344] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.178345] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.178684] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.324303] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.324305] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 14:39:36 Inspiron-530 kernel: [    2.324326] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 14:39:49 Inspiron-530 kernel: [   43.124776] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 14:39:49 Inspiron-530 kernel: [   43.124781] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.175962] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.175963] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.176178] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.332952] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.332953] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 14:57:27 Inspiron-530 kernel: [    2.332976] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 14:57:35 Inspiron-530 kernel: [   43.691117] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 14:57:35 Inspiron-530 kernel: [   43.691120] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:08:51 Inspiron-530 kernel: [  720.360982] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  739.977678] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  739.977680] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  739.977870] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  740.125056] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  740.125059] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:09:11 Inspiron-530 kernel: [  740.125084] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:09:13 Inspiron-530 kernel: [  741.792796] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:09:13 Inspiron-530 kernel: [  741.792801] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:24:02 Inspiron-530 kernel: [ 1630.908344] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.242935] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.242937] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.243129] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.389265] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.389268] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:24:18 Inspiron-530 kernel: [ 1647.396705] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:24:20 Inspiron-530 kernel: [ 1649.016840] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:24:20 Inspiron-530 kernel: [ 1649.016846] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:33:57 Inspiron-530 kernel: [ 2226.133018] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.810101] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.810103] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.810299] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.957284] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.957286] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:34:21 Inspiron-530 kernel: [ 2249.963290] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:34:23 Inspiron-530 kernel: [ 2251.972865] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:34:23 Inspiron-530 kernel: [ 2251.972871] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:40:02 Inspiron-530 kernel: [ 2590.893045] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:40:15 Inspiron-530 kernel: [ 2604.471066] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  1 15:40:15 Inspiron-530 kernel: [ 2604.471068] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:40:15 Inspiron-530 kernel: [ 2604.471511] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:40:16 Inspiron-530 kernel: [ 2604.650231] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:40:16 Inspiron-530 kernel: [ 2604.650235] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:40:16 Inspiron-530 kernel: [ 2604.657965] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:40:18 Inspiron-530 kernel: [ 2606.712880] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:40:18 Inspiron-530 kernel: [ 2606.712886] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:42:18 Inspiron-530 kernel: [ 2727.093999] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2736.991748] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2736.991749] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2736.991943] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2737.170145] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2737.170148] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:42:28 Inspiron-530 kernel: [ 2737.170264] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:42:30 Inspiron-530 kernel: [ 2738.772890] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:42:30 Inspiron-530 kernel: [ 2738.772895] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.186843] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.186844] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.187014] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.336951] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.336953] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:46:51 Inspiron-530 kernel: [    2.336975] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:46:58 Inspiron-530 kernel: [   42.592772] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:46:58 Inspiron-530 kernel: [   42.592777] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 15:54:59 Inspiron-530 kernel: [  524.364942] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.799126] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.799128] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.799319] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.978141] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.978145] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 15:55:18 Inspiron-530 kernel: [  542.996371] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 15:55:20 Inspiron-530 kernel: [  545.024783] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 15:55:20 Inspiron-530 kernel: [  545.024788] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 16:08:22 Inspiron-530 kernel: [ 1319.552337] e1000e: EEE TX LPI TIMER: 00000000
/var/log/kern.log.1:Dec  1 16:08:23 Inspiron-530 kernel: [ 1321.710279] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 16:08:23 Inspiron-530 kernel: [ 1321.710284] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 16:08:30 Inspiron-530 kernel: [ 1328.413583] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 16:08:31 Inspiron-530 kernel: [ 1330.030280] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 16:08:31 Inspiron-530 kernel: [ 1330.030286] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 16:21:49 Inspiron-530 kernel: [ 2127.739412] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.330280] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.330281] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.330474] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.503661] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.503664] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 16:22:01 Inspiron-530 kernel: [ 2139.508449] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 16:22:03 Inspiron-530 kernel: [ 2141.126324] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 16:22:03 Inspiron-530 kernel: [ 2141.126330] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 16:38:36 Inspiron-530 kernel: [ 3134.420610] Modules linked in: e1000e(OE) ptp pps_core input_leds nvidia_uvm(POE) dcdbas coretemp kvm_intel kvm irqbypass nvidia(POE) serio_raw snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer lpc_ich snd drm soundcore shpchp mac_hid binfmt_misc sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 hid_generic psmouse firewire_ohci uas i2c_i801 firewire_core pata_acpi usbhid crc_itu_t usb_storage hid floppy [last unloaded: pps_core]
/var/log/kern.log.1:Dec  1 16:56:25 Inspiron-530 kernel: [ 4199.044098] e1000e: EEE TX LPI TIMER: 00000000
/var/log/kern.log.1:Dec  1 16:56:26 Inspiron-530 kernel: [ 4200.531246] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 16:56:32 Inspiron-530 kernel: [ 4207.303870] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 16:56:32 Inspiron-530 kernel: [ 4207.303875] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.001732] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.001734] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.001887] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.202058] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.202062] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 22:39:10 Inspiron-530 kernel: [    2.202085] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 22:39:28 Inspiron-530 kernel: [   51.036770] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 22:39:28 Inspiron-530 kernel: [   51.036777] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.688068] e1000e: loading out-of-tree module taints kernel.
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.688232] e1000e: module verification failed: signature and/or required key missing - tainting kernel
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.688976] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.688976] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.689178] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.992653] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.992656] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  1 22:43:36 Inspiron-530 kernel: [   33.992681] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  1 22:43:44 Inspiron-530 kernel: [   44.277160] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 22:43:44 Inspiron-530 kernel: [   44.277165] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 22:44:39 Inspiron-530 kernel: [   98.608172] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 22:44:43 Inspiron-530 kernel: [  102.752826] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 22:44:43 Inspiron-530 kernel: [  102.752830] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  1 22:44:53 Inspiron-530 kernel: [  113.436145] e1000e: eth0 NIC Link is Down
/var/log/kern.log.1:Dec  1 22:45:07 Inspiron-530 kernel: [  126.808783] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  1 22:45:07 Inspiron-530 kernel: [  126.808788] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.662522] e1000e: loading out-of-tree module taints kernel.
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.662691] e1000e: module verification failed: signature and/or required key missing - tainting kernel
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.663429] e1000e: Intel(R) PRO/1000 Network Driver - 3.4.2.1-NAPI
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.663429] e1000e: Copyright(c) 1999 - 2018 Intel Corporation.
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.663629] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.868776] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 00:1d:09:78:01:cb
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.868778] e1000e 0000:00:19.0 eth0: Intel(R) PRO/10/100 Network Connection
/var/log/kern.log.1:Dec  2 07:36:20 Inspiron-530 kernel: [   33.868800] e1000e 0000:00:19.0 eth0: MAC: 7, PHY: 7, PBA No: FFFFFF-0FF
/var/log/kern.log.1:Dec  2 07:36:29 Inspiron-530 kernel: [   44.788703] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
/var/log/kern.log.1:Dec  2 07:36:29 Inspiron-530 kernel: [   44.788708] e1000e 0000:00:19.0 eth0: 10/100 speed: disabling TSO
(後略）