How To Force Routers To Refresh Their ARP Cache On DHCP?

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Is there some way, when I RAS-dial into a RRAS server, for the server to send a message to the default router telling it to refresh its ARP cache for the newly-assigned address?

When Win2000 boots, it broadcasts a "Gratuitous ARP" so that routers will refresh their ARP caches to the machine's current IP-MAC mapping. Is there any way to configure RRAS to broadcast a "Gratuitous ARP" for a newly-assigned client address, using its own MAC address as the mapping?

(This is a *real* problem when letting RRAS use DCHP addresses for incalling clients; if the router's ARP cache remembers some previous owner of that address, the new client will not be able to use the router to access the larger network.)
 
ARP caches usually run on very short storage times. XP and Server 2003
use two minutes by default, and it can be changed in the registry. Not sure
how you would check on what your router uses.

The other way around the problem is to give your remote clients IP
addresses in their own subnet (using a static pool) and routing them through
the RRAS server. That way the client MAC addresses don't appear on the LAN.

Theophilus said:
Is there some way, when I RAS-dial into a RRAS server, for the server to
Click to expand...
send a message to the default router telling it to refresh its ARP cache for
the newly-assigned address?
When Win2000 boots, it broadcasts a "Gratuitous ARP" so that routers will
Click to expand...
refresh their ARP caches to the machine's current IP-MAC mapping. Is there
any way to configure RRAS to broadcast a "Gratuitous ARP" for a
newly-assigned client address, using its own MAC address as the mapping?
(This is a *real* problem when letting RRAS use DCHP addresses for
Click to expand...
incalling clients; if the router's ARP cache remembers some previous owner
of that address, the new client will not be able to use the router to access
the larger network.)
 
Bill Grant said:
...give your remote clients IP addresses in their own subnet
(using a static pool) and routing them through the RRAS server.
Click to expand...

Thanks. Part of the problem is that I'm using 2000 Professional, not Server, so I don't have a nice RRAS MMC snap-in to set things up with. So, for instance, I have manually enabled the IPEnableRouter registry entry; but I don't know what else to adjust to make the static pool idea work. (I've tried a static pool, but then I can't get to anything.)

If I go with a static pool, don't I have to put a route in the router so that it can find my RRAS box to reply to those addresses? Or can RRAS actually proxy my traffic using it's own IP address? (That is, should I be experimenting with Internet Connection Sharing to NAT my traffic?) This application is for customer networks where I *don't* have access to their router configuration.
 
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