[LARTC] Promisc routing

[LARTC] Promisc routing

[Roy]

HI,

I want to set interface to promisc mode and do all routing with iptables.
Is it somehow possible? as I see now kernel do not pass everything to
ipables.

Basicaly I want to ignore ethernet addess and use only ip for routing.

I suppose this may require writting special kernel driver or it is possible
in other way?

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Re: [LARTC] Promisc routing

[Raúl Alexis Betancort Santana]

El Viernes 27 Agosto 2004 20:32, Roy escribió:
> HI,
>
> I want to set interface to promisc mode and do all routing with iptables.
> Is it somehow possible? as I see now kernel do not pass everything to
> ipables.
>
> Basicaly I want to ignore ethernet addess and use only ip for routing.
>
> I suppose this may require writting special kernel driver or it is possible
> in other way?

What are you trying to do?, what you have said is not posible, first because 
TCP/IP are not physical-layer protocols, that means that speaking about 
ethernet cards, you could not ignore ethernet adress.
You have to take into account on with ISO Network layer level you are 
speaking.
By the way .. what do you want to do?

Best regards
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Re: [LARTC] Promisc routing

[Andrew Ross]

On Sat, 2004-08-28 at 05:32, Roy wrote:
> I want to set interface to promisc mode and do all routing with iptables.

You don't need to set an interface in promisc mode to do routing. You
need the clients to have you configured as a router (easily acheived via
dhcp).

Routing isn't actually done with netfilter, although the routed packets
are available for filtering.

> Is it somehow possible?

Is it possible to use netfilter to make a routing decision? I suppose it
_might_ be (using the MARK target and iproute2), but it would be overly
convulted, esp compared to doing it "the normal way".

> I see now kernel do not pass everything to ipables.

I think you'll find that netfilter _does_ see all packets it's supposed
to see - it's just a matter of what chains they pass through.

Routed packets will pass through the FORWARD chains. Of course, this
won't happen unless you have configured your machine as a router, and
you have clients actually using it as a router (see above).

> Basicaly I want to ignore ethernet addess and use only ip for routing.

Um, that's what routing is (at least, in my understanding). You're
talking about a Layer 3 router, which makes routing decisions based on
IP addreses/subnets.

Cheers

Andrew

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