8.3. Interface Control Scripts

The interface control scripts activate and deactivated system interfaces. There are two primary interface control scripts, /sbin/ifdown and /sbin/ifup, that call on control scripts located in the /etc/sysconfig/network-scripts/ directory.

The ifup and ifdowninterface scripts are symbolic links to scripts in the /sbin/ directory. When either of these scripts are called, they require the value of the interface to be specified, such as:

ifup eth0


The ifup and ifdowninterface scripts are the only scripts that the user should use to bring up and take down network interfaces.

The following scripts are described for reference purposes only.

Two files used to perform a variety of network initialization tasks during the process of bringing up a network interface are /etc/rc.d/init.d/functions and /etc/sysconfig/network-scripts/network-functions. Refer to Section 8.4 Network Function Files for more information.

After verifying that an interface has been specified and that the user executing the request is allowed to control the interface, the correct script brings the interface up or down. The following are common interface control scripts found within the /etc/sysconfig/network-scripts/ directory:


Removing or modifying any scripts in the /etc/sysconfig/network-scripts/ directory can cause interface connections to act irregularly or fail. Only advanced users should modify scripts related to a network interface.

The easiest way to manipulate all network scripts simultaneously is to use the /sbin/service command on the network service (/etc/rc.d/init.d/network), as illustrated the following command:

/sbin/service network <action>

In this example <action> can be either start, stop, or restart.

To view a list of configured devices and currently active network interfaces, use the following command:

/sbin/service network status