Ubuntu 22.04桌面有线网络连接故障求助：Live CD可正常连接

Hey there, sorry to hear your wired connection's acting up on Ubuntu 22.04—good call checking the Live CD first, that tells us your hardware’s totally fine, so we just need to troubleshoot system-side configurations. Let’s walk through some practical steps to get your connection back:

• Check NetworkManager status
  Ubuntu relies on NetworkManager for most network management by default. First, verify it’s running:

  systemctl status NetworkManager
  

  If it shows "inactive", start it up and set it to launch on boot:

  sudo systemctl start NetworkManager
  sudo systemctl enable NetworkManager
  

• Reset NetworkManager configuration
  Corrupted config files are a common culprit. Back up your current config first, then reset to defaults:

  sudo cp /etc/NetworkManager/NetworkManager.conf /etc/NetworkManager/NetworkManager.conf.bak
  sudo nano /etc/NetworkManager/NetworkManager.conf
  

  Replace the file content with this default setup:

  [main]
  plugins=ifupdown,keyfile
  dns=dnsmasq
  
  [ifupdown]
  managed=true
  

  Save and exit (press Ctrl+O, hit Enter, then Ctrl+X), then restart NetworkManager:

  sudo systemctl restart NetworkManager
  

• Reinstall/update your network adapter driver
  Since the Live CD works, the driver might be corrupted on your installed system. First, identify your Ethernet adapter model:

  lspci | grep Ethernet
  

  For example, if you have a Realtek adapter, install the dedicated DKMS driver:

  sudo apt update && sudo apt install r8168-dkms
  

  Reboot your system after installation to apply changes.

• Manually configure a static IP
  Sometimes DHCP issues cause connection failures. First, find your network interface name:

  ip link show
  

  Then use nmcli to set a static IP (replace enp0s3, IP addresses, and connection name with your actual details):

  sudo nmcli con mod "Wired connection 1" ipv4.method manual ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.1 ipv4.dns 8.8.8.8,8.8.4.4
  sudo nmcli con up "Wired connection 1"
  

  You can check your existing wired connection names with nmcli con show.

• Reinstall NetworkManager entirely
  If all else fails, a fresh install of NetworkManager might fix hidden issues:

  sudo apt purge network-manager
  sudo apt install network-manager
  sudo reboot
  

Let me know if any of these steps resolve your issue, or if you run into specific errors—we can troubleshoot further!

备注：内容来源于stack exchange，提问作者mr dude