Re: Cable Modem [really responsible engineering]

["Wojtek Zlobicki" <wojtekz () idirect com>]

And have you ever arped for an IP not on your subnet (I am really opening
myself up here if I am wrong :) ?  ARP broadcasts
IIRC are sent to the MAC broadcast.  If your data link layer broadcast
domain consists of you and a router, you will not be able to get any other
MAC. You will only be able to see the MAC addresses of those in the MAC
broadcast domain.


----- Original Message -----
From: "PJ" <briareos () otherlands net>
To: "Wojtek Zlobicki" <wojtekz () idirect com>
Cc: <nanog () merit edu>
Sent: Wednesday, June 27, 2001 5:04 AM
Subject: Re: Cable Modem [really responsible engineering]


> On Tue, 26 Jun 2001, Wojtek Zlobicki wrote:
>
> > ----- Original Message -----
> > From: "Chris Adams" <cmadams () hiwaay net>
> > To: <nanog () merit edu>
> > Sent: Tuesday, June 26, 2001 9:20 PM
> > Subject: Re: Cable Modem [really responsible engineering]
> >
> > > Also, how do you prevent the user from trying to forge someone else's
> > > IP address or even MAC address in outgoing packets?  Without
protecting
> > > against forged packets, I don't see how to provide accountability when
> > > someone attacks.
> >
> > How would anyone find out anothers MAC.  As long as you seperate each
> > customer into their own bridge group, there is no way for them to find
> > anothers MAC.  As for forging IP's not much you can do about that.  MAC
> > address access list.. do they exists ?
>
> There is a neat little utility called arping that can return the MAC
address of a
> specified IP.  Comes in handy for bypassing MAC address filters.
>
> PJ
>
> --
> Security is mostly a superstition.  It does not exist in nature.
> -- Helen Keller