Sometimes you may want to disable a network connection. There are several different ways of achieving this.
It is likely that Network Manager is running your network connections. If so, you must disconnect from the network by disabling your network connection in Network Manager:
Find the Network Manager icon in the notification area. It should look like a small signal strength indicator or a computer monitor and will probably be close to the clock
Right-click the icon and uncheck Enable Networking
You should be disconnected from the network
If Network Manager is not running, use the Network Settings tool to disconnect your network connection:
Press ->->
Select the Connections tab
Uncheck your network connection to disconnect it
Press Close
ifdown is a command-line tool for disabling network connections.
To disable a network connection using ifdown:
Press ->-> to open a Terminal
Type sudo ifdown eth1 in the Terminal and press Return, replacing eth1 with the name of your network interface if it is different
Enter your password if prompted
Your network connection should be disconnected