12.3. Core Configuration
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## 12.3. Core Configuration

The principal location for system configuration information is `/etc/rc.conf`. This file contains a wide range of configuration information and it is read at system startup to configure the system. It provides the configuration information for the `rc*` files.

The entries in `/etc/rc.conf` override the default settings in `/etc/defaults/rc.conf`. The file containing the default settings should not be edited. Instead, all system-specific changes should be made to `/etc/rc.conf`.

A number of strategies may be applied in clustered applications to separate site-wide configuration from system-specific configuration in order to keep administration overhead down. The recommended approach is to place system-specific configuration into `/etc/rc.conf.local`. For example:

- `/etc/rc.conf`:

  sshd_enable="YES" keyrate="fast" defaultrouter="10.1.1.254"

- `/etc/rc.conf.local`:

  hostname="node1.example.org" ifconfig_fxp0="inet 10.1.1.1/8"

Distribute `/etc/rc.conf` to every system using `rsync` or a similar program, while `/etc/rc.conf.local` remains unique.

Upgrading the system using sysinstall(8) or `make world` will not overwrite `/etc/rc.conf`, so system configuration information will not be lost.

### Tip:

The configuration in `/etc/rc.conf` is parsed by sh(1). This allows system operators to create complex configuration scenarios. Refer to rc.conf(5) for further information on this topic.

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