nano /etc/conf.d/net
config_eth0=("192.168.24.203/24")
routes_eth0=("default via 192.168.24.1")

/etc/init.d/net.eth0 restart
 
nano /etc/udev/rules.d/70-persistent-net.rules
# This file was automatically generated by the /lib/udev/write_net_rules
# program, probably run by the persistent-net-generator.rules rules file.
#
# You can modify it, as long as you keep each rule on a single line.

# PCI device 0x1106:0x3065 (via-rhine)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:1f:f2:07:df:f9", NAME="eth0"

# PCI device 0x1106:0x3065 (via-rhine)
SUBSYSTEM=="net", DRIVERS=="?*", ATTRS{address}=="00:1f:f2:07:09:87", NAME="eth1"

Open the file /etc/udev/rules.d/70-persistent-net.rules with your favorite editor
Find the rule matching your MAC address
Change the NAME value from eth1 to eth0 i.e. NAME="eth0"
To apply changes without restarting run

sudo udevadm trigger