Remote MAC address on Windows

[Alex Tweedly]

J. Landman Gay wrote:
> Alex Tweedly wrote:
>> J. Landman Gay wrote:
>>>
>>> From what I read, the arp command is supposed to get what I need but 
>>> I can't make it work. I think that's because my server is a Mac. If 
>>> I had a Windows-only network it might work but I don't know how to 
>>> test it with my current setup. :(
>>>
>> I very much doubt that :-)
>> Whether the server is a Mac or a polka-dotted unicorn (??), if you 
>> can ping it, it pretty much has to have an arp association on the 
>> client machine :-)
>>
>> after you do the ping, does the arp table on the server have an entry 
>> for the client ?
>
> Well, I'm pinging from Parallels to the Mac, then doing the arp 
> command on the Windows/Parallels side. It says there are no entries at 
> all. I did use the -a flag. Sounds like maybe I'm doing it backwards? 
> It's the only way I can do it, since Parallels is my only functioning 
> Windows environment right now.
>
Sounds like you may be doing it right. I would be concerned that 
Parallels manages the network from their "Hypervisor", and may therefore 
"shield" (i.e. hide) such things as the ARP entries form the non-primary 
OSes.

In any case, there was nothing in your description that said to me "must 
be on same subnet", so as Luis said, arp is pretty much a loser once you 
need to handle a routed (multi-subnet) network; I'd look more into his 
suggestions of a script / file on the server which determines / holds 
its own MAC address.

In another email, you said
> If there is no reliable way to get the server's MAC address, I have a 
> problem.
The only way you can get even close to a "reliable way" is to run 
something on the server itself - anything else will fail in some case 
involving routed networks and/or proxy-arp and/or 
multi-network-interface machines (which Mac address is to be used ?).

Even then, you can still hit problems if the MAC address changes (e.g. 
servers running load-sharing or virtual network protocols).


-- 

Alex Tweedly      mailto:alex at tweedly.net      www.tweedly.net