Re: DHCP scanning

["Alex V. Lukyanenko" <y_avenger_y () ua fm>]

Hello Bénoni,

Wednesday, November 10, 2004, 9:44:42 PM, you wrote:

BM> Hi list !

BM> I was wondering if there was way to scan a network (a class
BM> C) to look for DHCP machines (I know I can ask the DHCP server,
BM> but I want to know what machines are under DHCP independly, and
BM> check after with what the DHCP server claims).

BM> I was thinking about creating such a plugin to report the
BM> results in Big Brother or Nagios. Developping it is not really a
BM> trouble, but I don't know exactly what checks do I have to
BM> perform, what queries send to the machines, ... 

BM> Any clue would be helpful !

You may want to sniff the network traffic for DHCP/BOOTP requests. They are
broadcast UDP datagrams sent to 255.255.255.255, and are clearly
marked as such by Ethereal.

-- 
Alex V. Lukyanenko | 86195208@icq | y_avenger_y () ua fm