I've seen speed problems between two NetBSD boxes because of duplex 
issues on the local Ethernet.  I'm not at all certain where the fault 
is, but how I have to set the interface on one of the boxes *changes* 
from time to time...  (The box in question is a Dell with a built-in 
3c905b.  Once upon a time, it didn't work at all with NetBSD without a 
kernel hack relating to duplex negotiation; that's been fixed, but 
perhaps the fix isn't quite right.  Or maybe it's just a weird 
switch....)

		--Steve Bellovin, http://www.research.att.com/~smb