Re: NIS/NFS alternatives? - dhcp
In article <[🔎] 20011007191421.B9403@harmony.cs.rit.edu>,
dman <dsh8290@rit.edu> wrote:
>On Sun, Oct 07, 2001 at 02:45:38PM +0200, Miquel van Smoorenburg wrote:
>| Even if you use a switch and put MAC address filters on the
>| switch an attacker can simply unplug an existing PC / laptop
>| and take over its MAC address.
>
>No, the MAC adress is in the ethernet card, not the outlet in the
>wall.
I know. But MAC addresses aren't hardcoded in the ethernet card-
they can easily be changed. "ifconfig eth0 hw ether 00:50:56:01:00:00"
et voila
>I even have actual experience with this. I have taken a laptop
>to school. In the 2 labs I spend most of my time in there are no
>spare ethernet jacks. I simply unplug one of the 'doze2k boxen and
>plug my woody laptop in. Still, even though I brought up the
>interface using DHCP and got an IP I could only reach the classs C I
>was on, the DNS server, and a certain web site. After talking with
>the admin of the labs I learned that ISC only routes host's whose MAC
>address is in their database and associated with a username. The web
>site I could access is the internal site used to register the MAC with
>the username. Now that I have registered the MAC I get routed
>properly.
But it's easy to forge someone else's mac address.
Mike.
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