[Ilugc] DHCP Servers List

[Binand Sethumadhavan]

On 19/10/05, Bharathi Subramanian <sbharathi at midascomm.com> wrote:
> Is it possible to get the list of DHCP Servers address on the current
> network ??  I tried to find it using TCP/UDP port scan technique. But
> No luck :(

Usually there is only one DHCP server in a given subnet. If you
suspect there are more, some of the things you can try are:

1. Scan the subnet on port 67/udp using Nmap: nmap -sU -p 67
192.168.100.0/24 (you will need root privileges to run nmap -sU).

2. Send out test DHCP requests and look at the IPs responding. Perl is
good - look up Net::DHCP or Net::DHCPClient on CPAN.

3. Try something like dhcp_probe -
http://www.net.princeton.edu/software/dhcp_probe/

Binand