How to Activate/Shut Down Your NIC
The ifup and ifdown commands can be used respectively to activate and deactivate a NIC interface. You must have an ifcfg file in the /etc/sysconfig/network-scripts directory for these commands to work. Here is an example for interface eth0:
[root@bigboy tmp]# ifdown eth0
[root@bigboy tmp]# ifup eth0
| 