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
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] 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