/etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
        address 192.168.1.250
        netmask 255.255.255.0
        gateway 192.168.1.1
        dns-nameservers 192.168.1.1 8.8.8.8

/etc/sysconfig/network-scripts/ifcfg-eth2

DEVICE=eth2
HWADDR=00:C0:DD:15:00:24
ONBOOT=yes
TYPE=Ethernet
IPADDR=192.168.0.21
NETMASK=255.255.255.0
NETWORK=192.168.0.0
BROADCAST=192.168.0.255

/etc/sysconfig/network

NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=hostname
GATEWAY=192.168.0.1
DNS1=192.168.0.1

ifdown eth2
ifup eth2

apt-get install ifenslave-2.6

echo bonding » /etc/modules

modprobe bonding

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

#p4p1 is manually configured, and slave to the "bond0" bonded NIC
auto p4p1
iface p4p1 inet manual
        bond-master bond0
        bond-primary p4p1

#eth0 ditto, thus creating a 2-link bond.
auto eth0
iface eth0 inet manual
        bond-master bond0

# bond0 is the bonding NIC and can be used like any other normal NIC.
auto bond0
iface bond0 inet manual
        bond-mode active-backup
        bond-miimon 100
        bond-slaves none

auto br0
iface br0 inet static
        address 192.168.0.250
        netmask 255.255.255.0
        gateway 192.168.0.1
        bridge_ports bond0
        bridge_hello 2
        bridge_stp off
        bridge_fd 9
        bridge_maxwait 12
        dns-nameservers 192.168.0.250
        dns-search n-t-i.ru n-t-i

1. Bring the network interfaces down, then
2. modify /etc/udev/rules.d/70-persistent-net.rules (or its equivalent)
3. re-load with udevadm control –reload-rules and finally
4. re-trigger with udevadm trigger –attr-match=subsystem=net
5. bring the network interfaces up.