Strange ARP Problem

[Jon Simmons]

I have a very strange ARP table problem.
Some of the machines on my network, both servers AND clients, both Win2k and
XP seem to be setting the hardware address of the Domain Controller to the
wrong Hardware Address.

The domain controller is a Win2000 with AD and DNS (AD integrated). It has
two network cards that are bridged for load balancing.

I have watched a client pinging this server constantly getting a speedy
response when suddenly the responses begin to time out, if
I check the ARP table (arp -a) at this time the dynamic entry for the
server's IP address has the incorrect hardware
address (it was correct while getting ping response), which is often similar
to the address of another server.
If I clear the ARP table (arp -d) the following ping requests respond.
This happens randomly and sometimes the problem "fixes itself".


If I understand how ARP works the hardware address should never change as
it's defined by the network card in the destination machine. Am I just
confused perhaps?

Can anyone help me figure out why this address might be changing and how to
stop it from happening?

Thanks
Jon

[Jon Simmons]

Oh, I thought of setting the address static in the ARP table, but it's not
as static as the documentation says as it's lost upon reboot and sometimes
just during the day for no reason. Also I would rather not set a static
address for this server as I would have to reset them all if the hardware on
the server changes. This server is my domain controller, so I couldn't make
that change in a GPO it would have to be done by hand at every client.


Thanks again
Jon


"Jon Simmons" <jon_nntp@jpsalaser.com> wrote in message
news:ucNhlSrXEHA.3156@TK2MSFTNGP12.phx.gbl...

>
> I have a very strange ARP table problem.
> Some of the machines on my network, both servers AND clients, both Win2k

and

> XP seem to be setting the hardware address of the Domain Controller to the
> wrong Hardware Address.
>
> The domain controller is a Win2000 with AD and DNS (AD integrated). It

has

> two network cards that are bridged for load balancing.
>
> I have watched a client pinging this server constantly getting a speedy
> response when suddenly the responses begin to time out, if
> I check the ARP table (arp -a) at this time the dynamic entry for the
> server's IP address has the incorrect hardware
> address (it was correct while getting ping response), which is often

similar

> to the address of another server.
> If I clear the ARP table (arp -d) the following ping requests respond.
> This happens randomly and sometimes the problem "fixes itself".
>
>
> If I understand how ARP works the hardware address should never change as
> it's defined by the network card in the destination machine. Am I just
> confused perhaps?
>
> Can anyone help me figure out why this address might be changing and how

to

> stop it from happening?
>
> Thanks
> Jon
>
>