我遇到了与描述类似的问题这里。我尝试了该帖子中的所有答案以及其他类似问题，但都没有成功。我对网络也一无所知，确实需要帮助。全新安装工作正常，但后来我可能运行了系统升级，从那时起互联网访问就中断了。我注意到一件事，当修改名称服务器行时/etc/resolv.conf ，NetworkManager 总是将其重置为 127.0.0.53。我尝试禁用该服务，删除 resolv.conf，但它总是返回。我会根据要求更新问题并提供任何额外信息。
我也尝试过这解决方案。但是当我 ping google.com 时，我得到：
ping: google.com:Temporary failure in name resolution
以下是相关输出lspci：
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
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@0000:03:00.0
logical name: enp3s0
version: 15
serial: 4c:cc:6a:2b:b7:05
size: 100Mbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=5.11.0-43-generic duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.0.105 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
resources: irq:19 ioport:d000(size=256) memory:df104000-df104fff memory:df100000-df103fff
我也尝试过以安全模式启动并从安装 USB启动，但同样的问题仍然存在。这不可能是硬件问题，因为我的 Windows 是双启动的，可以正常连接到互联网。我更新了上述内容：从安装闪存盘加载时，有线互联网可以正常工作。
以下是输出sudo service systemd-resolved：
systemd-resolved.service - Network Name Resolution
Loaded: loaded (/lib/systemd/system/systemd-resolved.service; disabled; ve>
Active: inactive (dead)
Docs: man:systemd-resolved.service(8)
...
重新启动服务后，我得到了以下信息：
systemd-resolved.service - Network Name Resolution
Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2022-01-21 16:03:30 EET; 9s ago
Docs: man:systemd-resolved.service(8)
https://www.freedesktop.org/wiki/Software/systemd/resolved
https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients
Main PID: 2826 (systemd-resolve)
Status: "Processing requests..."
Tasks: 1 (limit: 19082)
Memory: 4.7M
CGroup: /system.slice/systemd-resolved.service
└─2826 /lib/systemd/systemd-resolved
Starting Network Name Resolution...
Positive Trust Anchors:
systemd-resolved[2826]: . IN DS 20326 8 2
e06d44b80b8f1d39a95c0b0d7c65d08458e880409bbc683457104237c7f8ec8d
systemd-resolved[2826]: Negative trust anchors: 10.in-addr.arpa
16.172.in-addr.arpa 17.172.in-addr.arpa 18> systemd-resolved[2826]: Using system hostname 'sasmaster-ubuntu20'. systemd[1]:
Started Network Name Resolution.