Are LAN0 and LAN1 bridged in hardware?

[barryf]

@pacman

I think this is down to the Topaz chip at this stage.

[doron]

@barryf

So I’m not going crazy :-/

It’s like the Topaz chip will only operate the ports in “switch” mode and somehow over-rides the sw bridging’s usual operation. Just guessing here.

Not yet at least :-\

Note that “ifconfig br0 down” (or “ip link br0 down”) stops the bridging. “up” resumes.
So either the bridge driver is working closely with the hardware bridge switch chip, or we are just not listening at the right layer at the stack.
Time to read some kernel source code.

[boozel]

@barryf
I have the exact same problem. Lan0 and Lan1 bridged in the OS. iptables sending the packets to nfqueue but only broadcast shows up there.

On a side note please can you share your /etc/network/interfaces config if you are doing the bridging there.
If I uncomment the lan0, lan1 and bridge lines my DHCP on the wan prot stops working strangely. If i bring them up manually after boot then it works ok

# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto lo 
iface lo inet loopback

auto eth0
iface eth0 inet manual

allow-hotplug wan
iface wan inet dhcp

# First bridged interface
#allow-hotplug lan0
#iface lan0 inet manual
#    up ifconfig $IFACE 0.0.0.0 up
#    up ip link set $IFACE promisc on

# Second bridged interface
#allow-hotplug lan1
#iface lan1 inet manual
#    up ifconfig $IFACE 0.0.0.0 up
#    up ip link set $IFACE promisc on

#auto br0
#iface br0 inet manual
#  bridge_ports lan0 lan1
#  bridge_stp off

[doron]

@barryf

I think this is down to the Topaz chip at this stage.

It might be that tcpdump is just not listening at the right layer.

I don’t have a kernel with ebtables yet; are you able to filter frames that are unicast and are not destined to your box?
If you can, then perhaps you can also user ebtables to redirect them.

[barryf]

@boozel

Here is my interfaces for using wan plus a separate bridge. They all come up for me on boot.

auto lo 
iface lo inet loopback

auto eth0
iface eth0 inet manual

auto wan
iface wan inet dhcp

auto lan0
iface eth0 inet manual

auto lan1
iface eth0 inet manual
#
auto br0
iface br0 inet manual
        bridge_ports lan0 lan1
        bridge_stp off
        bridge_fd 0
        pre-up /sbin/ifconfig lan0 up
        pre-up /sbin/ifconfig lan1 up

Hope this helps.

[scaldwell]

I am also trying to use this hardware to monitor traffic by bridging those two interfaces. Looks like its been a while since anyone posted here. Anyone have any luck figuring this out? Or found different hardware better suited to the purpose? Any direction would be helpful, thanks!

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