This is an issue for 9.3 but still exists in 10.0 currently.  If you have
multiple interface cards, the first one (usually ethernet) will take precedence
over any other interfaces for assigning information via dhcp.  If the first
interface is disconnected but another interface is able to receive dhcp replies,
the network settings will never be set:

linux:~ # ps awwwx | grep dhcpcd
11149 tty1     S      0:00 /sbin/dhcpcd -C -D -K -N -t 999999 -h linux -c
/etc/sysconfig/network/scripts/dhcpcd-hook eth0
11682 ?        Ss     0:00 /sbin/dhcpcd -C -R -G -N -Y -t 999999 -h linux -c
/etc/sysconfig/network/scripts/dhcpcd-hook eth1

The -G -R -Y flags force the second interface to never set a default gateway or
any of the other settings necessary for dns resolution or routing.  The system
should detect if an interface is disconnected physically if possible and allow a
secondary interface to become the primary interface if necessary.  This would
simplify things tremendously for those of us with multiple ethernet interfaces
or ethernet and wireless interfaces who have to manually run dhcpcd each time to
configure any network settings.