Re: [LARTC] block ethernet IPv4 traffic

[Rene Gallati <lartc@draxinusom.ch>]

Anton Glinkov wrote:
>>Anton Glinkov wrote:
>>
>>
>>>On Mon, July 19, 2004 15:25, Ed Wildgoose said:
>>>
>>>
>>>>>the bridge thing is not possible.. the network is too big.. 300
>>>>>machines..
>>>>>with over 30 switches (only one of them is manageable) :(
>>>>>Basically I want to deny ethertype 0800 (IPv4) packets for that LAN.
>>>>>The only solution I thought of was to have a linux machine in this LAN
>>>>>that has all the possible IP addresses set on its interface.
>>>>>
>>>>>
>>>>
>>>>Look, we can't help you until you explain the problem
>>>>
>>>>WHY is it not possible to have a bridge?  This only requires two network
>>>>cards?
>>>
>>>
>>>I want to block the traffic between _ANY_ 2 of the machines in the
>>>network.
>>
>>How about giving them a netmask of /32 instead of /24 (or whatever you
>>have) so that they only see themselves in the same network and then
>>giving them a static route to the default gw (since it is outside of the
>>/32).
>>
>>Then you can block all inter-client traffic at that single default
>>gateway (or one hop "in front" of it, seen from the clients)
>>
> 
> 
> I don't have access to those machines :-)
> they use internet via different ehternet protocol (PPPoE)

If you don't have access to those machines, you need to do "something" 
where you have access which presumeably is at the switches. But that 
means you either need to replace those with smart ones (which can also 
be a linux box with many nics or multi-port nics) or basically put a 
linux box with 2 nics in between the cable from the client and the 
switch port. Either way, it's not gonna be cheap and possibly isn't 
feasible at all. I see no easier solution if you cannot control/trust 
the client systems.

-- 

C U

      - -- ---- ----- -----/\/  René Gallati  \/\---- ----- --- -- -
_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/