I'd like to do something like this. I have a domain, let's call
example.com. This domain has a set of users. I want to have email
accepted for any user in any hostname that is a part of this domain.
And, regardless of which hostname in this domain was involved, if the
user doesn't exist, the RCPT command should be rejected. This would
correspond to using a wildcard (e.g. a * label) in DNS for the zone
for that domain. The ability to make exceptions for this (e.g. a
special hostname in the domain handled differently) would be a plus,
but not essential. It seems what I need is some kind of RCPT command
time rewrite.
