kepo-ing Zz85

Mentioned in MIO is here, at last, I needed a bridge to trick/configure the router into recognising my 5th cat5e/ethernet wired pc.

A network bridge (before my cisco networking license and memory end soon)
* Connects 2 or more networks together
* Usually transparent in a network (unless an interface is created, like in a firewalled bridge, like in this case)
* A layer 2 device- less lag when compared a router (a layer 3 device) and therefore faster(?)
* Same broadcast domain, same subnet address
* Different collision domains, preventing the networks to split the wire’s bandwidth.

Here is a script I used to test out if my bridge could work

#bridgeman.sh
# Create the interface br0
/usr/sbin/brctl addbr br0

# Add the Ethernet interface to use with the bridge
/usr/sbin/brctl addif br0 eth0
/usr/sbin/brctl addif br0 eth1

# Start up the Ethernet interface
/sbin/ifconfig eth0 0.0.0.0
/sbin/ifconfig eth1 0.0.0.0

# Configure the bridge Ethernet
# The bridge will be correct and invisible ( transparent firewall ).
# It’s hidden in a traceroute and you keep your real gateway on the
# other computers. Now if you want you can config a gateway on your
# bridge and choose it as your new gateway for the other computers.
/sbin/ifconfig br0 192.168.1.66 netmask 255.255.255.0

run chmod +x bridgeman.sh

Note that the last line in the script was fairly important as I configure my router remotely via ssh. I first time I tried configuring a bridge, I added no interface the bridge, so by the time enabled the bridge interface, the linux box became transparent to the network and my ssh connection was dropped (that is different of course if you are configuring at the local terminal).

This is the configuration I used in /etc/network/interfaces for automatic startup/restart situations

# The bridge network interface(s)
auto br0
iface br0 inet dhcp
       bridge_ports eth0 eth1

Links
http://linux-net.osdl.org/index.php/Bridge
http://www.debian.org/doc/manuals/securing-debian-howto/ap-bridge-fw.en.html

http://forums.invisionpower.com/index.php?showtopic=187910
http://compsoc.dur.ac.uk/~djw/qemu.html
http://affix.sourceforge.net/affix-newdoc/Affix-enduser/x199.html