Different linux distribution vendors put their networking configuration files in different places in the filesystem. Here is a brief summary of the locations of the IP networking configuration information under a few common linux distributions along with links to further documentation.
Location of networking configuration files
RedHat (and Mandrake)
Interface definitions
/etc/sysconfig/network-scripts/ifcfg-*
Hostname and default gateway definition
/etc/sysconfig/network
Definition of static routes
/etc/sysconfig/static-routes
SuSe (version >= 8.0)
Interface definitions
/etc/sysconfig/network/ifcfg-*
Static route definition
/etc/sysconfig/network/routes
Interface specific static route definition
/etc/sysconfig/network/ifroute-*
SuSe (version <= 8.0)
Interface and route definitions
/etc/rc.config
Debian
Interface and route definitions
/etc/network/interfaces
Gentoo
Interface and route definitions
/etc/conf.d/net
Slackware
Interface and route definitions
/etc/rc.d/rc.inet1
The format of the networking configuration files differs significantly from distribution to distribution, yet the tools used by these scripts are the same. This documentation will focus on these tools and how they instruct the kernel to alter interface and route information. Consult the distribution's documentation for questions of file format and order of operation.
For the remainder of this document, many examples refer to machines in a hypothetical network. Refer to the example network description for the network map and addressing scheme.