| how egregious would it be to have, for example, "arp -p" reach down
| into the kernel and tickle it into arping the given default gateway
| intending only to elicit an arp reply?  the theory here being that if
| you can't arp the default gateway, it ain't a good gateway, regardless
| of whether it's filtering icmp (or other) or not.

It would be good to have a userland utility to be able
to issue/recieve arps just as we can do so with icmp
echo request.

Perhaps this could fill the void associated with
lacking an ethernet-level "ping" utility. I don't
think it belongs in the "arp" program, though...

For those not in the know, Ethernet in fact
deffines a "Configuration and Test Protocol" with
source-routing even (!), for doing layer two
pings. Very few hosts implement it, though
cisco routers do.

I did up an implementation a few years ago, I
periodically wonder if it's worth adding to NetBSD,
and then I decide that it's not too useful unless
it is widely deployed, which it is not...

--jhawk