Ubuntu 14.04中“Enable Wifi”选项消失，有线连接无网络求助

Hey there, I totally get how frustrating this is when you're still getting familiar with Ubuntu—let's work through some straightforward fixes to get your network sorted out.

Quick First Fix: Restart Network Manager #

This is the simplest and often most effective step for weird Network Manager glitches:

• Open a terminal with Ctrl+Alt+T
• Run this command (you'll need to enter your password, which won't show up on screen—this is normal):

  sudo systemctl restart NetworkManager
  

• Wait a few seconds, then check if the "Enable Wifi" option comes back, and if your wired connection starts working.

Check Your Network Drivers #

Missing or outdated drivers are a common culprit for both wifi and wired issues:

1. Open "Software & Updates" from your applications menu
2. Switch to the Additional Drivers tab
3. Look for any listed drivers for your wireless or wired network adapter
4. Select the recommended driver, click "Apply Changes", and restart your system after installation

If you prefer using the terminal to check your adapter first, run these commands to identify your hardware:

# For wireless adapters
lspci | grep Network

# For wired adapters
lspci | grep Ethernet

You can use the output to look up specific driver fixes if the Additional Drivers tab doesn't show options.

Verify Network Configuration & IP Address #

Sometimes your system isn't getting a valid IP address even if it says "connected":

• In the terminal, run:

  ip addr
  

• Look for your wired adapter (usually labeled something like enp0s3 or enpXsX)—it should have an inet line with an address like 192.168.x.x
• If there's no inet address, try forcing your system to request an IP from your router:

  sudo dhclient enp0s3  # Replace enp0s3 with your actual adapter name
  

Check Network Manager Configuration File #

Corrupted config settings can hide the wifi option:

1. First, back up the original config (just in case):

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

2. Open the config file with a text editor:

   sudo nano /etc/NetworkManager/NetworkManager.conf
   

3. Make sure the file looks like this (add any missing lines):

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

4. Save the file with Ctrl+O, press Enter, then exit with Ctrl+X
5. Restart Network Manager again with the first command above

Last Resort: Reinstall Network Manager #

If nothing else works, a fresh install of Network Manager might fix deeper issues:

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

Try these steps in order—start with the restart, since it's the fastest. Let me know if you run into any issues or need clarification on any step!

内容的提问来源于stack exchange，提问作者Nick Vandemark