Configuração de Rede

IPv4:

# cat /etc/sysconfig/network-scripts/ifcfg-eth0 
DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=none
IPADDR=192.0.2.30
PREFIX=24
GATEWAY=192.0.2.1
DNS1=203.0.113.200
DOMAIN=laboratorio.com.br
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth0"

IPv6:

# cat /etc/sysconfig/network-scripts/ifcfg-eth1 
DEVICE=eth1
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=yes
DNS1=2001:db8:cafe:dad0::200
DOMAIN="laboratorio.com.br laboratorio.com.br"
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
NAME="System eth1"
IPV6_AUTOCONF=no
IPV6_DEFAULTGW=2001:db8:cafe::
IPV6ADDR=2001:db8:cafe:dad0::30/48
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=yes
# cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=centos6.laboratorio.com.br
GATEWAY=192.0.2.1
IPV6_DEFAULTGW=2001:db8:cafe::

Referências: