Enabling network interfaces with no IP address
Note: RHEL 5 is used in this example.
# Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) DEVICE=eth1 ONBOOT=yes BOOTPROTO=none HWADDR=MAC address
Note that BOOTPROTO should either be none, or the line should not exist altogether. If BOOTPROTO is set to bootp or dhcp, and the boot protocol fails, the network interface will not be enabled.