Ubuntu – DHCP server on bridged connection

I want to put DHCP server on Ubuntu server to listen on 10.0.0.1 (internal network).
I also need to configure OpenVPN server on Ubuntu server (DHCP is going to lease addresses to OpenVPN clients), therefore I need to bridge one hardware interface (eth1) and one virtual interface (TAP from OpenVPN) in bridge mode (br0).

Where should I put DHCP to listen (on br0 or on eth1) ?
Should I put a gateway in the following configuration or not (if the DHCP listens on that interface) ?

I have the following configuration (/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 eth2
iface eth2 inet dhcp

# Other interfaces - not used
#auto eth0

# Internal interface - is now in bridge
#auto eth1 iface eth1 inet static
#     address 10.0.0.1
#     netmask 255.255.0.0

# Bridge
auto br0
iface br0 inet static
#ip, netmask, gateway
address 10.0.0.1
netmask 255.255.0.0
#gateway 10.0.0.1
#network interfaces on which to enable the bridge
bridge_ports eth1
#optional configuration if the machine is VM
#bridge_fd 9
#bridge_hello 2
#bridge_maxage 12
#bridge_stp off