Gratuitous ARP is a feature of Address Resolution Protocol in which a Gratuitous ARP request is sent by a host for its own IP Address while initiliazing. Gratuitous ARP requests are sent to ensure that the IPv4 address is not already in use on the locally attached subnet.
In Windows 2008 & Windows Vista, we can control the number of Gratuitous ARP requests sent and is set to “3″ by default. To modify the number of Gratuitous ARP entries sent (between 0 and 3)
To set or modify the number of Gratuitous ARP nrequests,
1. Click Start - Search and type “regedit”. This launches the WIndows Registry.
2. In the registry, navigate to the following registry key
3. In the right pane, right-click and select New – DWORD (32-bit value) and set its name as “ArpRetryCount” and set its value anything between “0″ and “3″. The value sets the number of Gartuitous ARP requests sent.
This should set the number of Gratuitous ARP requests sent.