Re: PPPoE on a bridge, nat sees bridge as incoming interface

[Georgi Georgiev <chutz@gg3.net>]

maillog: 06/03/2008-23:36:53(+0100): Pascal Hambourg types
> Hello,
>
> Georgi Georgiev wrote :
>> I am having trouble understaning how bridging and iptables fit together.
>> The situation that bugs me is: if I do a PPPoE connection over a bridge
>> with a single physical port, my nat table will see any incoming packet
>> as coming from the bridge interface, and not the ppp interface. Why?
>
> I guess you have a kernel 2.6.22 or above.
>
> From ChangeLog-2.6.22 :
>     [NETFILTER]: bridge-nf: filter bridged IPv4/IPv6 encapsulated in
>     pppoe traffic
>
>     The attached patch by Michael Milner adds support for using iptables
>     and ip6tables on bridged traffic encapsulated in pppoe frames,
>     similar to what's already supported for vlan.
>
> Setting the net.bridge.bridge-nf-filter-pppoe-tagged sysctl 
> (/proc/sys/net/bridge/bridge-nf-filter-pppoe-tagged) to 0 should disable 
> it.
>
> From <kernelsourcedir>/Documentation/networking/ip-sysctl.txt :
>
> bridge-nf-filter-pppoe-tagged - BOOLEAN
>     1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables.
>     0 : disable this.
>     Default: 1

The above did the trick with immediate effect. Thanks!

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