Troubleshooting internet connection
Once you’ve rebooted after editing your network interfaces file the first time, you may notice that your internet connection has gone bad and you are no longer receiving an active connection. You may notice a message over the network interface saying “device not managed”. This is because you altered the network configuration in the
/etc/network/interfaces for your two Ethernet ports. You can fix this by editing the network manager configuration file. You can open the /etc/NetworkManager/NetworkManager. conf file and change the line that says managed=false to true . Save the file and restart the network manager with the following: $ sudo service network-manager restart
Alternatively, I recommend setting up a wireless connection here or just make sure you had everything downloaded beforehand. If you need to reverse this, simply roll back the changes in the interfaces file and restart the computer. If you are experiencing other issues, be sure to check the Ubuntu documentation at https:// help.ubuntu.com/community/IptablesHowTo. The official Ubuntu documentation provides a lot of good information on not only how to fix problems, but how to edit configurations to add additional functionality such as logging.