ARP cache renewal

I have hundreds of network devices I am testing, all on the same IP address.
Each time I change devices, I have to wait 2 minutes for the ARP cache to
timeout. If I attempt any activity within that time it fails, but the ARP
cache restarts the timer.

The device does Gratuitous ARP at power up, but Windows is ignoring that.

I do not wish to clear the ARP cache from the command line every time: my
hands are full. Even waiting 3 minutes is not a bad as that. I am looking
for a better way.

Is there any way I can (1) Change the ARP timeout interval or (2) Get
Windows to recognise Gratuitous ARP?

(david)

Thank You.

In the end I used the registry settings:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Tcpip\Parameters]
"ArpCacheMinReferencedLife"=dword:0000001e
"ArpCacheLife"=dword:0000001e

to set the ARP timeout interval to 30 seconds (the defaults in XP are 120 &
180)

Vista does not use these entries, but Vista defaults to 30 & 45 seconds
anyway.

(david)


"Olivier C." <v-(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> Hello David ,
>
> Here's the solution :
>
> How to change the ARP timeout interval ? :
>
>
> See Option DHCP 35 in DHCP.(RFC 2132)
> http://www.faqs.org/rfcs/rfc2132.html
>
>
> Get Windows to recognise Gratuitous ARP?
>
> http://www.windowsreference.com/wind...windows-vista/
>
> http://wiki.wireshark.org/Gratuitous_ARP
>
> Client-Side Conflict Detection
> With the evolution of smarter client operating systems such as Windows
> 2000 and
> Windows XP, conflict detection has been integrated into the client side of
> the DHCP
> leasing process. A process called gratuitous arp defines the steps by
> which a client attempts to
> determine if its offered IP lease is already in use on its network
> segment.The DHCP client
> sends a gratuitous arp request on the local subnet for the offered IP
> address. If it receives a
> positive reply, it knows the address is already in use and sends a
> DHCPDECLINE message
> back to the DHCP server.Then the client requests another address.
>
>
> Regards,
>
>
> Olivier C.
>
> Microsoft Customer Service and Support.
>
>
> ################################################## ##
>
> "david" <(E-Mail Removed)> wrote in message
> news:eyHpymc$(E-Mail Removed)...
>>I have hundreds of network devices I am testing, all on the same IP
>>address. Each time I change devices, I have to wait 2 minutes for the ARP
>>cache to timeout. If I attempt any activity within that time it fails, but
>>the ARP cache restarts the timer.
>>
>> The device does Gratuitous ARP at power up, but Windows is ignoring that.
>>
>> I do not wish to clear the ARP cache from the command line every time: my
>> hands are full. Even waiting 3 minutes is not a bad as that. I am
>> looking for a better way.
>>
>> Is there any way I can (1) Change the ARP timeout interval or (2) Get
>> Windows to recognise Gratuitous ARP?
>>
>> (david)
>>
>
>