airodump-ng mon0 not woking with eth2 interface [duplicate]

Question

I am new to ubuntu os.I have installed aircrack successfully and trying to execute the command sudo airodump-ng mon0 but its not working.How to fix this issue ?

Error:

ubuntu@ubuntu:~$ sudo airmon-ng start waln0


Found 4 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after
a short period of time, you may want to kill (some of) them!
-e 
PID Name
1382    avahi-daemon
1383    avahi-daemon
1433    NetworkManager
14727   wpa_supplicant


Interface   Chipset     Driver

eth2        Unknown         wl

ubuntu@ubuntu:~$ sudo airodump-ng mon0
Interface mon0: 
ioctl(SIOCGIFINDEX) failed: No such device

also tried with eth2 interface but no luck!

ubuntu@ubuntu:~$ sudo airmon-ng start eth2

iwconfig

ubuntu@ubuntu:~$ iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

eth2      IEEE 802.11  Access Point: Not-Associated   
          Link Quality:5  Signal level:0  Noise level:0
          Rx invalid nwid:0  invalid crypt:0  invalid misc:0

ppp0      no wireless extensions.

Answer 1

The system is telling you exactly what the problem is:

Found 4 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after
a short period of time, you may want to kill (some of) them!

PID Name
1382    avahi-daemon
1383    avahi-daemon
1433    NetworkManager
14727   wpa_supplicant

You want to kill all of the above processes (by using kill <PID> as a superuser).

After that, everything else should work just as expected.