Catalin Bucur:
> For an existing domain but without MX, I receive the error /"Host or
> domain name not found. Name service error for name=onedomain.com
> type=MX: Host not found, try again)"/, but AFTER
> /maximal_queue_lifetime/, which is very annoying. In this case the
> sender finds out only after 5 days about the real problem.
This is a problem with your DNS resolver WHICH IS NOT PART OF
POSTFIX. You need to use a better DNS resolver.
With a properly functioning resolver:
$ host -t mx www.postfix.org
www.postfix.org has no MX record
Wietse