Ubuntu – How to fix “ioctl(SIOCGIFINDEX) failed: No such device”

Usually you get that answer when you try to monitor an interface which has no IP address assigned (probably not connected).

The output from ip addr shows that only one of your interfaces has an IP address, namely usb0.

So sudo nethogs usb0 should finally give the desired result.

As there are comments mentioning different interfaces: if ip addr shows several interfaces with IP-addresses assigned there are two options for you:

• ip route show | grep default will show you the one device that is used to access "everything outside". e.g.
  default via 192.168.0.253 dev eth1 proto static metric 100 tells me I have to use sudo nethogs eth1
• If your goal is to look at internal traffic (within a local network or even between virtual machines on the same host) you can try with all devices found by ip addr or ip link.

I finally found a nice trick to have airmon-ng working as it is supposed to; without any need to "check kill" or turn off completely network manager. By the way It is network manager that is the cause of the problem since the version 0.9.8.10.

1. Open your network manager configuration file as root in order to edit it

sudo gedit /etc/NetworkManager/NetworkManager.conf

2. Add the following lines to prevent network manager from interfering with airmon-ng

[keyfile]
unmanaged-devices=interface-name:wlan0mon;interface-name:wlan1mon;interface-name:wlan2mon;interface-name:wlan3mon;interface-name:wlan4mon;interface-name:wlan5mon;interface-name:wlan6mon;interface-name:wlan7mon;interface-name:wlan8mon;interface-name:wlan9mon;interface-name:wlan10mon;interface-name:wlan11mon;interface-name:wlan12mon    #  avoid conflicts with airmon-ng

The wlanXmon interfaces are just for monitor mode... So there is no problems if network manager can't manage them : It shouldn't!
You can add as many interfaces as you want, 12 should be enough unless you are a addicted to buy wireless USB. Use the separator ; between every interfaces.

3. Saves the changes. Effects are immediate: you can now use mode monitor on one interface while you are connected to the Internet through network manager with another interface.

Solution previously published in aircrack-ng forum > Edit NewtorkManager.conf to prevent conflicts with airmon-ng (no check kill)