unknown IP delivering DHCP

[Dirty Mortain <dirtymortain () gmail com>]

Hello.

In my LAN I'm using the network 192.0.0.0/24 with a DHCP (192.0.0.14)
delivering for the entire LAN through 3 smart switches.
Yesterday I found a machine which have received 192.168.2.3 as DNS
server by the DHCP, in 192.0.0.14 there is no configuration pointing
to this so I tried to find that machine.
It looks like a Linux 2.4 box which had 80 open with HTTP
authentication (default admin/admin but changed) and DHCP open which
only delivers DNS (overwrites 192.0.0.14, it always reply after it).
Since switches are "smart" (not that smart indeed) I have no
configuration interface where I could create a VLAN and/or block that
MAC. Because it is a broadcast I cannot block it on the firewall
(since it doesn't pass through it) what can I do to both know which
machine is it (a smart and humanized machine) and block it?


Thanks.

------------------------------------------------------------------------
Securing Apache Web Server with thawte Digital Certificate
In this guide we examine the importance of Apache-SSL and who needs an SSL certificate.  We look at how SSL works, how 
it benefits your company and how your customers can tell if a site is secure. You will find out how to test, purchase, 
install and use a thawte Digital Certificate on your Apache web server. Throughout, best practices for set-up are 
highlighted to help you ensure efficient ongoing management of your encryption keys and digital certificates.

http://www.dinclinx.com/Redirect.aspx?36;4175;25;1371;0;5;946;e13b6be442f727d1
------------------------------------------------------------------------