I just had something a little scary happen, so I thought I’d share it in case anyone else hits this problem.

I’m in Portland for OSCON and suddenly the wireless networking on my laptop stopped working. The wireless status showed as “off” but it wouldn’t turn on. I’m running Linux Mint Debian Edition (LMDE) and no interfaces were showing up.

Now, one thing I like about open source is I always tend to learn something when trying to solve a problem. A quick search on my phone introduced me to the “rfkill” command:

# rfkill list
0: phy0: Wireless LAN
	Soft blocked: no
	Hard blocked: yes

For some reason, the interface was “Hard blocked”. I then figured out what must have happened.

I was trying to bring up a shell to diagnose another issue. On Linux this tends to be ALT+CTL+Fx where the function key chosen is the virtual terminal you want (i.e. F1 for the first one, F2 for the second, etc.). On my normal keyboard, which is an old Apple keyboard, the function keys default to softkeys and you have to hold down the Fn key to actually trigger F1, F2, etc.

This is not the case with my laptop, so when I hit Fn+F2 it turned on “airplane mode”. This was causing the hard block.

I hit it again:

# rfkill list
0: phy0: Wireless LAN
	Soft blocked: yes
	Hard blocked: no
1: hci0: Bluetooth
	Soft blocked: no
	Hard blocked: no

And then turned off the soft block:

orcrist interfaces.d # rfkill unblock 0

And it fixed my issue:

orcrist interfaces.d # rfkill list
0: phy0: Wireless LAN
	Soft blocked: no
	Hard blocked: no
1: hci0: Bluetooth
	Soft blocked: no
	Hard blocked: no

It would have really sucked to be on the road and have some serious software issue to repair with no network access, so I was extremely relieved to figure this out.