How to fix network after mistake with aircrack-ng in Kali Linux?

I had the same issue. After messing around with airmon-ng I couldn't connect to any networks. Even the network manager icon disappeared from the taskbar (KDE). If I checked iwconfig, I would see eth0, lo, and wlan0mon instead of just wlan0. Doing:

ifconfig wlan0 up

just told me no such device exists. That clued me into how to potentially fix the mode.

Here are the commands that restored my Internet access:

First, restart your network manager:

 service NetworkManager restart

(Your network manager service might be called Network-Manager.)

Let's see what your wireless adapter is doing:

 iwconfig

(It might be called something like wlan0mon instead of wlan0, indicating it is still in monitor mode.)

Since it is still in monitor mode, let's turn the normal mode back on:

 airmon-ng start wlan0 7

(The last number is the channel and can probably be omitted.)

Now let's stop the monitoring interface:

 airmon-ng stop wlan0mon

And finally, let's turn your normal network adapter back on:

 ifconfig wlan0 up

Check for the normal adapter now:

 ifconfig

(Should no longer show the "mon" equivalent and instead show wlan0 or whatever your adapter is called in normal mode.)

Now you can use your network manager app to reconnect to the network for browsing.

Not sure why I haven't seen this solution. Most end up rebooting to get back to normal Internet mode.

There should be super domain permission required to run airmon-ng. So try:

sudo airmon-ng eth0 start

Using eth0 start won't work because eth0 isn't a command.

Use ip link set dev eth0 up instead, to bring up the interface.

If you need to assign an address to the interface use ip a add 192.168.1.200/24 dev eth0