Re: Problem when WinXP firewall is activated (does not reply to ping)

According to 
http://technet2.microsoft.com/WindowsServer/en/library/75cd0e1f-f464-40ea-ac88-2060e6769f331033.mspx?mfr=true

DHCP client computers running Windows 2000 or Windows XP that obtain an 
IP address use a gratuitous ARP request to perform client-based conflict 
detection before completing configuration and use of a server offered IP 
address. If the DHCP client detects a conflict, it will send a DHCP 
decline message (DHCPDECLINE) to the server.

If your network includes legacy DHCP clients (clients running a version 
of Windows earlier than Windows 2000), you can use server-side conflict 
detection provided by the DHCP Server service under specific 
circumstances. For example, this feature might be useful during failure 
recovery when scopes are deleted and recreated.

--Raphael



Rune Kock wrote:
> On 12/1/06, Raphaël HUCK <raphael.huck-HH44TBFINEIAvxtiuMwx3w@xxxxxxxxxxxxxxxx> 
> wrote:
> > There is a problem when the firewall of Windows XP is activated, as it
> > does not reply to ping, and dnsmasq checks with ping whether an IP
> > address is already attributed before giving it to someone.
> >
> > As Windows XP doesn't reply to ping when its firewall is activated,
> > dnsmasq thinks the address isn't in use, and gives it to someone else.
>
> Back in July, when I asked about using arping rather than ping, Simon 
> replied:
>
> > Interestingly DHCP clients do the address-in-use check too, and since
> > the client only needs to check the local network, it does use ARP.
>
> As I understand it, the client should try an arping before using the
> address it has been given by the server.
>
> The interesting question is whether WinXP actually implements this
> arping.  If Windows follows the specification on this, there should be
> no point in the server using arping.
>
>
> Rune