> That was the part that would have been indicative.  It probably showed a
> From: line of [log in to unmask], correct?
> Administrator@* is part of the built-in filter.

From: "POSTMASTER" <[log in to unmask]>

> Actually this bounced to the right place.

Yep. Sorry, I checked the FAQ and archives, read the doc, but couldn't
see how they related to the "From:" in the actual bounce.

It's very clear now and makes perfect sense, as I expected :)

Thanks,

Peter