> +1 to Mark's comments... Without discovery you'll never know if you're over
> the limits or not.
That's not the point though. It might be fine today. But at any time any one
of those providers could change a record you are including from them, and take
you over the limit, effectively a DoS
Envelope sender often manifests itself in the Return-Path:. This /should/ only
be added by the final delivering system based on the envelope sender as it was
handed the message, but who knows how many final delivery systems do add it,
and what do they do if an inbound message already has a Retu
