[ih] Some Questions over IPv4 Ownership

[Dave CROCKER]

On 10/15/2010 12:08 PM, Jorge Amodio wrote:
> I always thought email routing as end-to-end,

but it ain't.

the 'routing' that we are used to thinking about is actually only between border 
MTA's.  In a sense, the standard use of MX is like the role of BGP, which leaves 
open the question of interior routing.  (That's most often also done with 
internal MXs.)


> I don't see further forwarding by the receiving MX host as "routing".

but alas, it is exactly that.


Because quite a lot of email is between very large ISPs, there is a tendency to 
believe that modern email is only one-hop.  This misses all sorts of legitimate 
and very present scenarios, especially between enterprises.

d/

-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net