Segue abaixo meus arquivos da rede.
DEVICE=eth0
BOOTPROTO=none
BROADCAST=10.1.1.255
IPADDR=10.1.1.5
NETMASK=255.255.255.0
ONBOOT=yes
DEVICE=eth1
BOOTPROTO=none
BROADCAST=172.0.0.255
IPADDR=172.0.0.1
NETMASK=255.255.255.0
ONBOOT=yes
e network
NETWORKING=yes
FORWARD_IPV4=yes
HOSTNAME=firewall
GATEWAY=10.1.1.1
GATEWAYDEV=eth0
#NOZEROCONF=yes