[e2e] Transparent subnets with Proxy Arp

[Jerry Zeitgeisty]

What was so bad about using proxy ARP to implement transparent
subnets a la RFC 1027? (aside from being a violation of the e2e 
principle)

The Host Requirements RFC includes a comment about it 
interfering with transport layer dynamics.  And some other
references mentioned problems when an ARP table maps
several hosts to a single MAC.  In both cases the actual
problems weren't described.

Any help on this would be much appreciated.  Thanks!

- Eric Goldman