Ubuntu 16.04系统更新后WiFi热点无法正常连接求助

Hey there, sorry to hear your hotspot stopped working after those system updates—let’s walk through some fixes that’ve worked for me and others in similar situations.

1. Check Core Network Services First #

Updates sometimes glitch out background services. Let’s make sure the ones powering your hotspot are running properly:

• Open a terminal and check Network Manager status:
  systemctl status NetworkManager

  Look for "active (running)" in the output. If it’s not running, start it with sudo systemctl start NetworkManager and set it to launch on boot: sudo systemctl enable NetworkManager

• Next, verify the DHCP service (dnsmasq) that handles device connections:
  systemctl status dnsmasq

  If it’s inactive, fire it up with sudo systemctl start dnsmasq and enable it permanently: sudo systemctl enable dnsmasq

2. Inspect Hotspot Configuration Files #

Updates can overwrite or corrupt network configs. Let’s check your hotspot’s settings:

• Navigate to the Network Manager config folder:
  cd /etc/NetworkManager/system-connections/
• List your saved connections to find your hotspot:
  ls -la (look for a file named after your hotspot)
• Open the config file with nano (replace [your-hotspot-name] with the actual name):
  sudo nano [your-hotspot-name]

  Make sure these sections are present and correct:

  [ipv4]
  method=shared
  [ipv6]
  method=ignore
  

  Save with Ctrl+O, press Enter, then exit with Ctrl+X. Restart Network Manager to apply changes: sudo systemctl restart NetworkManager

3. Reset Network Manager to Defaults #

If configs are totally messed up, a fresh start might help:

• Stop Network Manager first: sudo systemctl stop NetworkManager
• Backup your current configs (just in case): sudo mv /etc/NetworkManager /etc/NetworkManager.bak
• Reinstall Network Manager: sudo apt-get install --reinstall network-manager
• Start it back up: sudo systemctl start NetworkManager
• Now recreate your hotspot from scratch using the system settings panel.

4. Rule Out Driver Problems #

Wireless drivers can get broken during updates. Let’s check your adapter:

• List your wireless hardware:
  lspci | grep Wireless (for internal adapters) or lsusb | grep Wireless (for USB adapters)
• Check if the driver is loaded (replace [driver-name] with your adapter’s driver, e.g., iwlwifi for Intel):
  lsmod | grep [driver-name]

  If the driver seems missing or faulty, try reinstalling firmware: sudo apt-get install --reinstall linux-firmware

5. Test Hotspot via Command Line #

Sometimes the GUI hotspot tool has bugs—let’s create one via terminal to test:

• Turn off your wireless adapter first: nmcli radio wifi off
• Run these commands to set up a hotspot (replace MyHotspot and your-password-here with your details):

  nmcli con add type wifi ifname wlan0 con-name MyHotspot autoconnect no ssid MyHotspot
  nmcli con modify MyHotspot 802-11-wireless.mode ap 802-11-wireless.band bg ipv4.method shared
  nmcli con modify MyHotspot wifi-sec.key-mgmt wpa-psk
  nmcli con modify MyHotspot wifi-sec.psk "your-password-here"
  

• Start the hotspot: nmcli con up MyHotspot
• If this works, the issue is with the GUI tool. You can stick with the terminal method or reinstall the network GUI: sudo apt-get install --reinstall network-manager-gnome

6. Check Firewall Settings #

A misconfigured firewall might block hotspot traffic. Let’s open the necessary ports:

• Check UFW status: sudo ufw status
• If it’s active, allow hotspot-related traffic:

  sudo ufw allow in on wlan0
  sudo ufw allow out on wlan0
  sudo ufw allow in on virbr0
  sudo ufw allow out on virbr0
  

  The virbr0 interface is used for shared network connections.

If none of these steps work, try booting into an older kernel from the GRUB menu (under "Advanced options for Ubuntu")—if the hotspot works there, the problem is tied to the latest kernel update, and you can hold off on kernel updates until a fix is released.

内容的提问来源于stack exchange，提问作者Raghav Menon