Hi SO community!
I thought it was worth documenting some things I discovered while debugging a "wifi not working" issue for either others to find, or for the community to find a more appropriate place to document / raise an issue (
per github).
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Preconditions
SO Version: 16.04.6.2
Network Interfaces:
- on-board wifi
- on-board ethernet
During installation of SO, I connected to a WiFi network to update packages during install etc.
After installation, I launched into the GUI and used the same said WiFi network. WiFi networks were visible from the network-manager GUI embedded in the top menu bar.
I then ran stage 1 of the setup installer configuring the wifi device for management and the ethernet device for monitoring.
Issue
After rebooting I could wireless networks were no longer detected by the network-manager GUI embedded in the top menu bar.
I followed a number of standard Ubuntu guides for WiFi debugging:
Working from low-level up I could not located any issues from the output of:
- lshw
- lsmod
- iwconfig
- rfkill list
iwlist scan would not produce any output (indicating a problem), however sudo iwlist scan did show available networks indicating that the device itself was not to blame.
I eventually came across the command nmcli device status which had my WiFi device listed as "unmanaged".
"Fix"
I edited /etc/network/interfaces and commented out the lines for my WiFi device.
I then restarted the network manager service (sudo systemctl restart network-manager).
nmcli device status then showed my WiFi device connecting to my network. The network-manager embedded GUI in the top menu bar also correctly showed the network.
In summary the issue seems to be that the setup script uses /etc/network/interfaces to manage the network interfaces which causes network-manager to lose the ability to manage the WiFi device.
Related Threads
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I hope this information helps.
I don't currently have the ability to copy output / take screen grabs from my SO device so I hope the description above is enough.