Backup of network connection before change to Google DNS

Changing DNS server settings on Ubuntu

In the System menu, click Preferences, then click Network Connections.
Select the connection for which you want to configure Google Public DNS. For example:
- To change the settings for an Ethernet connection, select the Wired tab, then select your network interface in the list. It is usually called Auto eth0.
- To change the settings for a wireless connection, select the Wireless tab, then select the appropriate wireless network.
Click Edit, and in the window that appears, select the IPv4 Settings tab.
- Before change Menthod: Automatic(DHCP)
If the selected method is Automatic (DHCP), open the dropdown and select Automatic (DHCP) addresses only instead. If the method is set to something else, do not change it.
In the DNS servers field, enter the Google Public DNS IP addresses, separated by a space: 8.8.8.8 8.8.4.4
Click Apply to save the change. If you are prompted for a password or confirmation, type the password or provide confirmation.
Test that your setup is working correctly; see Testing your new settings below.
Repeat the procedure for additional network connections you want to change.