[ih] Some Questions over IPv4 Ownership

[Larry Sheldon]

On 10/15/2010 1:23 PM, Dave CROCKER wrote:
> 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.)

We used aliases files to tell the boundary MTA where to route the 
incoming email traffic.

I believe some of the departments had further distributions.

And within the organization, we had email portability, if people 
followed the example at example.com address structure because we could 
update the control aliases file pretty quickly when people moved from 
one department to another.

And even mail you perceive as "one hop" very likely made several hops 
within ${DepartureISP}, maybe a couple through ${spamFilkterHouse} and 
more than one within ${terminatingISP} to your mbox.

If your client will show them to you, look at (and count) the Received: 
headers on messages you read.