Ist das Modul für Deine Netzwerkkarte geladen? Normalerweise legt man die Netzwerkgeräte in der rc.conf fest.
Hier mal meine:
#
# /etc/rc.conf - Main Configuration for Arch Linux
#
#
# -----------------------------------------------------------------------
# LOCALIZATION
# -----------------------------------------------------------------------
#
# LOCALE: available languages can be listed with the 'locale -a' command
# HARDWARECLOCK: set to "UTC" or "localtime"
# TIMEZONE: timezones are found in /usr/share/zoneinfo
# KEYMAP: keymaps are found in /usr/share/kbd/keymaps
# CONSOLEFONT: found in /usr/share/kbd/consolefonts (only needed for non-US)
# CONSOLEMAP: found in /usr/share/kbd/unimaps
# USECOLOR: use ANSI color sequences in startup messages
#
LOCALE=de_DE.utf8
HARDWARECLOCK="UTC"
TIMEZONE=Europe/Berlin
KEYMAP=de-latin1-nodeadkeys
CONSOLEFONT=
CONSOLEMAP=
USECOLOR="yes"
#
# -----------------------------------------------------------------------
# HARDWARE
# -----------------------------------------------------------------------
#
# Scan hardware and load required modules at bootup
MOD_AUTOLOAD="yes"
# Module Blacklist - modules in this list will never be loaded by hwdetect
MOD_BLACKLIST=()
#
# Modules to load at boot-up (in this order)
# - prefix a module with a ! to disable it
#
MODULES=(it87)
# Scan for LVM volume groups at startup, required if you use LVM
USELVM="no"
#
# -----------------------------------------------------------------------
# NETWORKING
# -----------------------------------------------------------------------
#
HOSTNAME="athlon64"
#
# Interfaces to start at boot-up (in this order)
# Declare each interface then list in INTERFACES
# - prefix an entry in INTERFACES with a ! to disable it
#
# Note: to use DHCP, set your interface to be "dhcp" (eth0="dhcp")
#
lo="lo 127.0.0.1"
eth0="dhcp"
INTERFACES=(lo eth0)
#
# Routes to start at boot-up (in this order)
# Declare each route then list in ROUTES
# - prefix an entry in ROUTES with a ! to disable it
#
gateway="default gw 192.168.0.1"
ROUTES=(!gateway)
#
# Enable these network profiles at boot-up. These are only useful
# if you happen to need multiple network configurations (ie, laptop users)
# - set to 'menu' to present a menu during boot-up
# - prefix an entry with a ! to disable it
#
# Network profiles are found in /etc/network-profiles
#
#NET_PROFILES=(main)
#
# -----------------------------------------------------------------------
# DAEMONS
# -----------------------------------------------------------------------
#
# Daemons to start at boot-up (in this order)
# - prefix a daemon with a ! to disable it
# - prefix a daemon with a @ to start it up in the background
#
DAEMONS=(syslog-ng @network dbus hal alsa @cups @httpd @mysqld)
# End of file