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Re: bridge firewall with kernel 2.4.22


bridging is not routing! A bridge forwards frames at leyer 2, a router forwards ip packets at leyer 3. However iptables is a 3rd leyer firewall, therefore bridged traffic is not affected by any iptables rule!

Francisco Oliveira wrote:


I have compiled kernel 2.4.22 for bridge and iptables support.

Bridge is working ok but Layer 3 packets are only processed if they are addressed to bridge box ip address interface.


hostA --------------Bridgebox-------------------------Router------------Remote locations

hostA ip address

BridgeBox ip addres

Router ip address

Remote locations ip addres Any

If I write a rule into the bridgebox to deny all forwarding traffic for Any destination, and router ip addres as hostA default gateway. Packets are not processed by bridge box and are routed by router
In this case packets are bridged by the bridgebox (at leyer 2) an routed by the router.

If the same rule is written with bridge box as hostA default gateway works ok

Here the ip packet is goind through the 3rd leyer of the bridgebox (are routed by it) and iptables rules are processed.

I would like bridegebox process all ip traffic throught it

Exclude the interface ot the router from the bridge.

Best regards,
   Tibor Repasi

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