不确定问题是否确实与 BIOS 更新有关，但我最近做了一个包括 CMOS 重置的操作。
我使用的是 Debian 10（稳定版）并拥有 500/200 Mbps 的互联网连接，现在似乎上限为 100/100 Mbps。
我使用与以前完全相同的 UTP 电缆，但也尝试使用其他电缆，结果是相同的。
我的主板是华擎 B450 Pro4，相关规格如下：
- PCIE x1 千兆位 LAN 10/100/1000 Mb/s
- 瑞昱RTL8111H
输出ethtool enp8s0：
Settings for enp8s0:
Supported ports: [ TP AUI BNC MII FIBRE ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Link partner advertised pause frame use: Symmetric
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 1000Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000033 (51)
drv probe ifdown ifup
Link detected: yes
和lshw -C network：
*-network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci@0000:08:00.0
logical name: enp8s0
version: 15
serial: 70:85:c2:be:21:ba
size: 1Gbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp aui bnc mii fibre 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=r8169 duplex=full ip=192.168.1.128 latency=0 link=yes multicast=yes port=MII speed=1Gbit/s
resources: irq:38 ioport:d000(size=256) memory:fcb04000-fcb04fff memory:fcb00000-fcb03fff
速度测试结果：
我想弄清楚这是 BIOS/硬件/ISP 问题还是我的配置错误。
我真的很感激任何建议。
答案1
这是路由器的问题。
重新启动它，将电缆插入另一个端口，现在似乎工作正常。