[wplug] Clearing arp cache

[Brian Sammon]

> Arp -d *.*.*.*
> 
> In Redhat 9 Linux this give an error about an unknown host.  
> 
> If I type merely arp -a, I get prompted for a host name.  

Apparently, this depends on which version of arp you have.
On my system, arp is part of net-tools 1.60, and "arp -a" lists the arp cache. 
I can't find an arp parameter to clear the arp cache.
Also arp (my version) doesn't support wildcards.