[Bridge] linux bridging problem

richardvoigt at gmail.com richardvoigt at gmail.com
Thu Aug 21 21:34:19 PDT 2008

On Thu, Aug 21, 2008 at 8:39 PM, Brodie, Laura (Mission Systems)
<Laura.Brodie at ngc.com> wrote:
> Help please,
> My goal is to create a bridge to do traffic shaping for a subnet.
> I am trying to create a bridge following the Linux Foundation sample
> setup in a VMware CentOS guest OS (before the router) using the
> commands:
>        brctl addbr br0
>        brctl addif br0 eth0
>        brctl addif br0 eth1
>        ifconfig eth0 down
>        ifconfig eth1 down
>        ifconfig eth0 up
>        ifconfig eth1 up
>        ifconfig eth1
> The problem: A flood of ARP requests from the Vyatta machine
> ( looking for the DNS Server ( on the upper
> network shuts down the entire network.

ARP requests are almost never issued in floods.  Most likely you have
a bridging loop duplicating the packets (maybe without reducing TTL)
and multiplying the traffic a thousand-fold.  Consider enabling
spanning tree or break the bridging loop.

Also, you should put IP addresses on the bridge, not the member
interfaces.  Try:

ifconfig eth0 up
ifconfig eth1 up
ifconfig br0 up

as your last three entries.

> Thanks,
> Laura Lee

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