DHCP Conflict Detection & Win 7 Firewall..

Question

       This may be a stupid question, but I can't quite find the answer....
   We have a small network, about 200 computers (Server 2012), Win 7 workstations (Very Few XP's left)
  I had one workstation detect an IP conflict (XP if it makes any difference), and it just was assigned another address
and it was on its merry way.   I took a look at the DHCP server and realized that I never turned on DHCP Conflict detection.
I turned it on and set it for 1 attempt. 
    So for  the heck of it I pinged the workstation and DNS worked but ping is blocked on the workstations firewall.
    Which made me wonder if I should push out a GP to allow ping to all the workstations????  (Question 1)
     Question  two:  If I do that to all the workstations, what would stop it from happening if someone brings a "guest"
     laptop into the building??
           What would be best options? or is it working as it should and I am just Paranoid!! LOL
                           Thank You in advance for any advice
                                           Wolverine..

Answer 1

Hi,
According to
this article, Client computers running Windows Server 2008, Windows Vista, Windows Server 2003, Windows XP, Windows 2000, Windows NT 4.0, Windows Millennium Edition, and Windows 98 automatically check to determine if an IP address is already in use before
using it. I think this behavior still exists in windows server 2012.
On the server-side, when a DHCP client requests a lease, a DHCP server checks its pool of available addresses and assigns the client a lease on an available IPv4 address. By default, the server checks only the list of current leases to determine whether an
address is available. It doesn’t actually query the network to see whether an address is in use. If you enable address conflict detection, the DHCP server uses the ping process to test available scope IP addresses before including these addresses in DHCP lease
offers to clients.
In addition, each additional conflict detection attempt delays the DHCP server response by a second while waiting for the ping request to time out. This increases the load on the server, so it is not recommended to set the value greater than two for ping attempts.
Hope this helps!
Best regards,
Susie