我全新安装了Ubuntu 18.04从可启动 USB。
我的主板PRIME Z390-A有一个英特尔 I219-V 千兆网卡网卡。
我已经尝试修复这个问题好几天了，但这非常烦人，因为这块主板没有 WiFi。
以太网电缆可与笔记本电脑配合使用（Windows 和 Ubuntu 均适用）。
在网络设置中，我可以看到有线连接，并且其状态一直在“连接 - 100Mb/s”和“电缆已拔出”之间交替（尽管电缆一直插着）。
我找到了几个类似的帖子，但这些修复方法都对我不起作用。具体来说，我尝试过重启电脑和路由器、重启网络服务、进入 /etc/NetworkManager/NetworkManager.conf 并将行 managed=false 更改为 managed=true、运行不同的 Ubuntu 版本 (16.04) 以及从可启动 pendrive 运行实时安装，但这些方法都无法解决问题。
以下是这些线程中请求的一些典型命令的输出：
1. dmesg | grep e100
$ dmesg | grep e100
[ 1.430346] e1000e: Intel(R) PRO/1000 Network Driver - 3.2.6-k
[ 1.430346] e1000e: Copyright(c) 1999 - 2015 Intel Corporation.
[ 1.430476] e1000e 0000:00:1f.6: Interrupt Throttling Rate (ints/sec) set
to dynamic conservative mode
[ 1.634976] e1000e 0000:00:1f.6 0000:00:1f.6 (uninitialized): registered PHC clock
[ 1.703178] e1000e 0000:00:1f.6 eth0: (PCI Express:2.5GT/s:Width x1) 04:92:26:c3:b1:67
[ 1.703179] e1000e 0000:00:1f.6 eth0: Intel(R) PRO/1000 Network Connection
[ 1.703237] e1000e 0000:00:1f.6 eth0: MAC: 13, PHY: 12, PBA No: FFFFFF-0FF
[ 1.703760] e1000e 0000:00:1f.6 eno1: renamed from eth0
[ 18.339438] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[ 18.339445] e1000e 0000:00:1f.6 eno1: 10/100 speed: disabling TSO
[ 19.140294] e1000e: eno1 NIC Link is Down
[ 22.031793] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[ 22.031795] e1000e 0000:00:1f.6 eno1: 10/100 speed: disabling TSO
[ 22.824304] e1000e: eno1 NIC Link is Down
[ 25.571979] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[ 25.571986] e1000e 0000:00:1f.6 eno1: 10/100 speed: disabling TSO
[ 26.368188] e1000e: eno1 NIC Link is Down
[ 85.064039] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[ 85.064046] e1000e 0000:00:1f.6 eno1: 10/100 speed: disabling TSO
[ 85.848304] e1000e: eno1 NIC Link is Down
等等...
2. ip -ca
ip -c a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
link/ether 04:92:26:c3:b1:67 brd ff:ff:ff:ff:ff:ff
3. 使用 lspci -nnk 命令检查grep 0200 -A2
lspci -nnk | grep 0200 -A2
00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet Connection (7) I219-V [8086:15bc] (rev 10)
Subsystem: ASUSTeK Computer Inc. Ethernet Connection (7) I219-V [1043:8672]
Kernel driver in use: e1000e
4. systemctl status NetworkManager.service --no-pager -l
systemctl status NetworkManager.service --no-pager -l
● NetworkManager.service - Network Manager
Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
Active: active (running) since Sun 2019-03-03 14:38:32 CET; 1h 12min ago
Docs: man:NetworkManager(8)
Main PID: 840 (NetworkManager)
Tasks: 3 (limit: 4915)
CGroup: /system.slice/NetworkManager.service
└─840 /usr/sbin/NetworkManager --no-daemon
mar 03 15:50:41 janek-ubuntu NetworkManager[840]: <info> [1551624641.4199] device (eno1): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
mar 03 15:50:41 janek-ubuntu NetworkManager[840]: <info> [1551624641.4201] dhcp4 (eno1): activation: beginning transaction (timeout in 45 seconds)
mar 03 15:50:41 janek-ubuntu NetworkManager[840]: <info> [1551624641.4210] dhcp4 (eno1): dhclient started with pid 4113
mar 03 15:50:41 janek-ubuntu dhclient[4113]: DHCPDISCOVER on eno1 to 255.255.255.255 port 67 interval 3 (xid=0x55484130)
mar 03 15:50:44 janek-ubuntu dhclient[4113]: DHCPDISCOVER on eno1 to 255.255.255.255 port 67 interval 7 (xid=0x55484130)
mar 03 15:50:44 janek-ubuntu NetworkManager[840]: <info> [1551624644.9622] device (eno1): carrier: link connected
mar 03 15:50:51 janek-ubuntu dhclient[4113]: DHCPDISCOVER on eno1 to 255.255.255.255 port 67 interval 9 (xid=0x55484130)
mar 03 15:50:51 janek-ubuntu NetworkManager[840]: <info> [1551624651.9679] device (eno1): state change: ip-config -> unavailable (reason 'carrier-changed', sys-iface-state: 'managed')
mar 03 15:50:52 janek-ubuntu NetworkManager[840]: <info> [1551624652.0003] dhcp4 (eno1): canceled DHCP transaction, DHCP client pid 4113
mar 03 15:50:52 janek-ubuntu NetworkManager[840]: <info> [1551624652.0003] dhcp4 (eno1): state changed unknown -> done
我很乐意提供额外的上下文和命令输出。很难想出下一步该做什么。
答案1
来自评论...
现有配置仅能以 100M 连接，经常断开连接，而以太网接口为 1G。这肯定表明存在潜在的电缆问题。
我们更换了电缆，现在其工作速度为 1G。