我正在运行 Arch Linux。在 dmesg 中我有以下消息：
[ 3.225860] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 8.405807] e1000e: eth0 NIC Link is Down
[ 39.495793] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 44.679494] e1000e: eth0 NIC Link is Down
[ 110.525785] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 115.709482] e1000e: eth0 NIC Link is Down
[ 344.245735] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
我确实在此链接上使用 IPv6（它连接到电缆调制解调器），并且我确实需要此链接准备就绪。请注意，“未准备好”并不是一个短暂的问题。在我手动调出它之前，它根本没有准备好。
雷击后我不得不更换主板。执行此操作后，eth0（主板上的）不会自动出现，但 Intel PCI 卡（以太网服务器适配器 I340-T4）上的 4 个端口会自动出现。该主板具有 Intel 以太网 (I219-V)。 （请参阅下面的 lspci 输出。）
我尝试了以下操作但没有成功：
netctl reenable eth0-profile
该链接仍然无法自动出现。ip a显示此链接已关闭。netctl status显示失败：
netctl status eth0-profile
● netctl@eth0\x2dprofile.service - WAN
Loaded: loaded (/etc/systemd/system/netctl@eth0\x2dprofile.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Wed 2017-06-28 02:14:27 EDT; 11min ago
Docs: man:netctl.profile(5)
Process: 329 ExecStart=/usr/lib/network/network start %I (code=exited, status=1/FAILURE)
Main PID: 329 (code=exited, status=1/FAILURE)
Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.
手动运行下一个命令会不是给予成功：
netctl start eth0-profile
该系统有绝不有一个启用的 systemd 单元[电子邮件受保护]（甚至是通用的全接口 dhcpcd 服务）。如果这能解决问题，我并不反对添加一个，但以前没有它就可以工作，我想回到之前的状态。 （我有 btrfs 快照，但我不想回滚。我想了解发生了什么并进行更正，以便我从中学到一些东西。）
要解决我的链接问题，我必须运行以下命令。
sudo ip link set eth0 up
sudo dhcpcd -n eth0
sudo systemctl restart dnsmasq
一旦我运行这些命令，一切都很好。由于某种原因，它只是没有自动启动。运行这些命令时，我注意到这ip link set eth0 up需要很长时间。有时我必须运行多次。
更新1
/etc/netctl/eth0-配置文件：
Description='WAN'
Interface=eth0
Connection=ethernetvpn
IP='dhcp'
lspci-v
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (2) I219-V (rev 31)
Subsystem: ASUSTeK Computer Inc. Device 8672
Flags: bus master, fast devsel, latency 0, IRQ 143
Memory at f7400000 (32-bit, non-prefetchable) [size=128K]
Capabilities: [c8] Power Management version 3
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [e0] PCI Advanced Features
Kernel driver in use: e1000e
Kernel modules: e1000e
01:00.0 Ethernet controller: Intel Corporation 82580 Gigabit Network Connection (rev 01)
Subsystem: Intel Corporation Ethernet Server Adapter I340-T4
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at f7180000 (32-bit, non-prefetchable) [size=512K]
Memory at f720c000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
Capabilities: [70] MSI-X: Enable+ Count=10 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-1b-2c-3d-4e-5f-6a-7b
Capabilities: [1a0] Transaction Processing Hints
Capabilities: [1c0] Latency Tolerance Reporting
Kernel driver in use: igb
Kernel modules: igb
01:00.1 Ethernet controller: Intel Corporation 82580 Gigabit Network Connection (rev 01)
Subsystem: Intel Corporation Ethernet Server Adapter I340-T4
Flags: bus master, fast devsel, latency 0, IRQ 17
Memory at f7100000 (32-bit, non-prefetchable) [size=512K]
Memory at f7208000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
Capabilities: [70] MSI-X: Enable+ Count=10 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-1b-2c-3d-4e-5f-6a-7b
Capabilities: [1a0] Transaction Processing Hints
Kernel driver in use: igb
Kernel modules: igb
01:00.2 Ethernet controller: Intel Corporation 82580 Gigabit Network Connection (rev 01)
Subsystem: Intel Corporation Ethernet Server Adapter I340-T4
Flags: bus master, fast devsel, latency 0, IRQ 18
Memory at f7080000 (32-bit, non-prefetchable) [size=512K]
Memory at f7204000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
Capabilities: [70] MSI-X: Enable+ Count=10 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-1b-2c-3d-4e-5f-6a-7b
Capabilities: [1a0] Transaction Processing Hints
Kernel driver in use: igb
Kernel modules: igb
01:00.3 Ethernet controller: Intel Corporation 82580 Gigabit Network Connection (rev 01)
Subsystem: Intel Corporation Ethernet Server Adapter I340-T4
Flags: bus master, fast devsel, latency 0, IRQ 19
Memory at f7000000 (32-bit, non-prefetchable) [size=512K]
Memory at f7200000 (32-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
Capabilities: [70] MSI-X: Enable+ Count=10 Masked-
Capabilities: [a0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-1b-2c-3d-4e-5f-6a-7b
Capabilities: [1a0] Transaction Processing Hints
Kernel driver in use: igb
Kernel modules: igb
更新2
我还没有找到解决办法。将这两行添加到 /etc/netctl/eth0-profile 中似乎暂时解决了这个问题，但问题又回来了。
TimeoutUp=300
TimeoutCarrier=300
我发现了一些新信息。最近一次启动后，日志显示以下问题：
Sep 12 03:38:26 arch2 network[358]: Duplicate Address Detection is taking too long on interface 'eth0'
Sep 12 03:38:27 arch2 network[358]: Failed to bring the network up for profile 'eth0-profile'
Sep 12 03:38:27 arch2 dhcpcd[588]: script_runreason: /usr/lib/dhcpcd/dhcpcd-run-hooks: Terminated
我可以这样启动网络：
# netctl restart eth0-profile
之后，一切正常。但是，我想找到并解决根本问题。
这是 systemctl status“netctl@eth0\x2dprofile.service”的输出
● netctl@eth0\x2dprofile.service - ETH0
Loaded: loaded (/etc/systemd/system/netctl@eth0\x2dprofile.service; enabled; vendor preset: disabled)
Active: active (exited) since Tue 2017-09-12 03:47:54 EDT; 36s ago
Docs: man:netctl.profile(5)
Process: 870 ExecStart=/usr/lib/netctl/network start eth0-profile (code=exited, status=0/SUCCESS)
Main PID: 870 (code=exited, status=0/SUCCESS)
Status: "online"
Tasks: 2 (limit: 4915)
CGroup: /system.slice/system-netctl.slice/netctl@eth0\x2dprofile.service
├─ 963 dhcpcd -4 -q -t 30 -L eth0
└─1070 dhcpcd -6 -q -t 30 eth0
Sep 12 03:47:59 arch2 dhcpcd[1050]: eth0: soliciting an IPv6 router
Sep 12 03:47:59 arch2 dhcpcd[1050]: eth0: Router Advertisement from ff00::bbda:ffff:fe44:2dee
Sep 12 03:47:59 arch2 dhcpcd[1050]: eth0: adding address 2001:333:300:1c6:dd09:189b:cf5b:bbbb/64
Sep 12 03:47:59 arch2 dhcpcd[1050]: eth0: adding route to 2601:343:380:1f6::/64
Sep 12 03:47:59 arch2 dhcpcd[1050]: eth0: adding default route via ff00::bbda:ffff:fe44:2dee
Sep 12 03:47:59 arch2 dhcpcd[1050]: forked to background, child pid 1070
Sep 12 03:47:59 arch2 dhcpcd[1070]: eth0: confirming prior DHCPv6 lease
Sep 12 03:47:59 arch2 network[870]: Started network profile 'eth0-profile'
Sep 12 03:48:09 arch2 dhcpcd[1070]: eth0: failed to confirm prior address
Sep 12 03:48:09 arch2 dhcpcd[1070]: eth0: soliciting a DHCPv6 lease
答案1
我的解决方案相当简单。我将这两行添加到 /etc/netctl/eth0-profile 中：
TimeoutUp=300
TimeoutCarrier=300
答案2
我的解决方案是将以下行添加到此接口的 netctl 配置文件（在 /etc/netctl 中）：
SkipDAD=yes
系统启动速度比以往任何时候都快，并且错误均已解决。
这是一个通过一根以太网电缆直接连接到电缆调制解调器的盒子。这就是整个网络，永远不会有其他系统连接。所以 DAD 没有任何有用的目的，据我所知。但它造成了真正的问题。跳过 DAD 对我来说很有意义，尽管我确信有人会说这是错误的解决方案。这是我在过去 3 个月中找到的最佳解决方案，它使系统的启动效果比以往任何时候都好。