Re: Linksys assigned IP to unknown DHCP client???

From: Walter Roberson (
Date: 11/16/02

From: (Walter Roberson)
Date: 16 Nov 2002 07:21:56 GMT

In article <>,
aladin <> wrote:
:I have noticed that my DHCP clients table has been showing UNKNOWN
:DHCP clients!!! I only have 2 computers using my cable modem, but on
:the DHCP clients table, it showed weird IP addresses that are outside
:of the DHCP IP range I assigned. The MAC address seems to be spoofed
:too... Any exploits out there for this type of behavior?

My understanding is that cable modems see all the broadcasts
for the entire block/group served by the common copper trunk
but filter the non-broadcast traffic except to your assigned IP.

The implication would be that you would be seeing MAC addresses
for a number of machines that you wouldn't be able to reach by IP.

I understand that this broadcast behaviour is necessary in order
to support establishing the session in order to get an IP address
to work with.

I am not a cable modem user; I've merely seen the behaviour mentioned

Positrons can be described as electrons traveling backwards in time.
Certainly many Usenet arguments about the past become clearer when they
are re-interpreted as uncertainty about the future.
   -- Walter Roberson