Red Hat LINUX 7.2 Reference Manual page 188

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The two primary interface control scripts in the /etc/sysconfig/network-scripts direc-
tory, ifdown and ifup, are symbolic links to the scripts in the /sbin directory. When either of
these scripts are called, they accept a value of the interface to be used, such as:
[root@bleach network-scripts]# ifup eth0
Determining IP information for eth0... done.
[root@bleach network-scripts]#
At that point, the /etc/sysconfig/network-scripts/network-functions and
/etc/rc.d/init.d/functions files are sourced and functions from those files are used to
perform a variety of tasks. See Section 12.3, Network Functions for more information about these
tasks.
After verifying that an interface has been specified and that the user executing the request is allowed
to bring the interface up or down, the correct script for the type of interface device is called into action.
This is the script that actually brings the interface up and down. The following interface control scripts
are the most common of this type:
• ifup-aliases — Configures IP aliases from interface configuration files when more than one
IP address is associated with an interface.
• ifdown-cipcb and ifup-cipcb — Used to bring Crypto IP Encapsulation (CIPE) con-
nections up and down.
• ifdown-ipv6 and ifup-ipv6 — Contains IPv6-related function calls that utilize the envi-
ronment variables in various interface configuration files and /etc/sysconfig/network.
• ifup-ipx — Used to bring up an IPX interface.
• ifup-plip — Used to bring up a PLIP interface.
• ifup-plusb — Used to bring up a USB interface for network connections.
• ifdown-post and ifup-post — Contains commands to be executed after a particular inter-
face is brought up or down, such as configuring IP aliases or routes by calling certain scripts, such
as ifup-aliases or ifup-routes.
• ifdown-ppp and ifup-ppp — Used to bring a PPP interface up or down using a particular
device.
• ifup-routes — Adds static routes for a particular device as its interface is brought up.
• ifdown-sit and ifup-sit — Contains function calls related to bringing up and down an
IPv6 tunnel within an IPv4 connection.
• ifdown-sl and ifup-sl — Used to bring an SLIP interface up or down.
Chapter 12:Network Scripts