我正在使用 Ubuntu 16.04 LTS，连接以太网电缆后，系统显示已连接图标。
但过了几秒钟，系统显示断开连接警报。以下是日志：
Oct 25 19:09:40 note dbus[769]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Oct 25 19:09:40 note systemd[1]: Starting Network Manager Script Dispatcher Service...
Oct 25 19:09:40 note dbus[769]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Oct 25 19:09:40 note systemd[1]: Started Network Manager Script Dispatcher Service.
Oct 25 19:09:40 note nm-dispatcher: req:1 'down' [enp19s0]: new request (1 scripts)
Oct 25 19:09:40 note nm-dispatcher: req:1 'down' [enp19s0]: start running ordered scripts...
鲁宁sudo lshw -C net
*-network
description: Network controller
product: BCM4313 802.11bgn Wireless Network Adapter
vendor: Broadcom Corporation
physical id: 0
bus info: pci@0000:12:00.0
version: 01
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list
configuration: driver=bcma-pci-bridge latency=0
resources: irq:17 memory:fbb00000-fbb03fff
*-network
description: Ethernet interface
product: AR8152 v2.0 Fast Ethernet
vendor: Qualcomm Atheros
physical id: 0
bus info: pci@0000:13:00.0
logical name: enp19s0
version: c1
serial: f0:4d:a2:d7:11:90
capacity: 100Mbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.1-NAPI latency=0 link=no multicast=yes port=twisted pair
resources: irq:32 memory:fba00000-fba3ffff ioport:e000(size=128)
*-network DISABLED
description: Wireless interface
physical id: 2
logical name: wlp18s0b1
serial: c0:cb:38:9c:4d:f6
capabilities: ethernet physical wireless
configuration: broadcast=yes driver=brcmsmac driverversion=4.4.0-43-generic firmware=610.812 link=no multicast=yes wireless=IEEE 802.11bgn