Creating a bridge in linux
Debian and/or Ubuntu  --  By Rodney Richison

First, download the tools we need.

    apt-get install uml-utilities bridge-utils


Now lets edit the /etc/network/if-pre-up.d/uml-utilities file.


Change
                chmod 660 /dev/net/tun
          to
                chmod 666 /dev/net/tun
    NOTE: Make sure your not in /etc/network/if-up.d/uml-utilites
                While a file with the same name exists, there is no chmod line



Now, be sure to make a backup copy of your current setup.

    cp /etc/network/interfaces /etc/network/interfaces.beforetap

Below you will see an example of a working bridge with four taps assigned.
You may assign more if you'd like.

############ /etc/network/interfaces ###################

#Here is an example of the /etc/network/interfaces file

###############################################

# The loopback network interface
auto lo
iface lo inet loopback

# Taps should be before br0
auto tap0
iface tap0 inet manual
tunctl_user rodney
uml_proxy_arp 192.168.0.2
uml_proxy_ether eth0

auto tap1
iface tap1 inet manual
tunctl_user rodney
uml_proxy_arp 192.168.0.2
uml_proxy_ether eth0

auto tap2
iface tap2 inet manual
tunctl_user rodney
uml_proxy_arp 192.168.0.2
uml_proxy_ether eth0

auto tap3
iface tap3 inet manual
tunctl_user rodney
uml_proxy_arp 192.168.0.2
uml_proxy_ether eth0

auto tap4
iface tap4 inet manual
tunctl_user rodney
uml_proxy_arp 192.168.0.2
uml_proxy_ether eth0


# Ip address is same as eth0 would have been.
auto br0
iface br0 inet static
address 192.168.0.2
netmask 255.255.255.0
gateway 192.168.0.1
bridge_ports eth0 tap0 tap1 tap2 tap3 tap4
bridge_maxwait 0


# The primary network interface
auto eth0
iface eth0 inet manual

############################################