How to display a message each time eth1 is enabled?

After some searches, I found a way how you can do it:

• First, disable the usual notification from Network Manager. How? Your answer is here:

  • How to disable notification from network-manager

• Run a script to notify you every time internet connects. How? Here is your answer:

  • How to run a script, depending on internet connection

• How you can get notified from a script? Again, there are answers on Stack Exchange in this sense:

  • Is there a way to show notification from bash script in Ubuntu?
  • Sound notification in Ubuntu terminal

You can add a shell script into /etc/NetworkManager/dispatcher.d that you might name 99-notification. Be sure to mark it executable with chmod +x 99-notification.

In that script, you will need to do something with the input to script, the interface name and the action.

#/bin/bash

if [[ "$1" = eth1 ]] && [[ "$2" = up ]]
then
    DISPLAY=:0.0 kdialog --passivepopup "eth1 is enabled" 3
fi

I have not tested this, but I think it will work, at least with KDE. For Unity/Gnome, you might have to exchange kdialog with zenity.