The arp problem which I reported a few months ago has been cured by
ISS. The problem would occur when my gateway was having
problems. Eventually no arp requests would go onto the wire because
the device buffers (confirmed with printk) were full then suddenly
arp would work but small bits of memory seemed to be missing. I had
accepted the explanation that it was a flakey ethernet card and the
memory leak was something else. Now arp works 100% and the memory
leak is gone.
Wheee, I did something right ;-)