Open relay test (was: Bounce/System Notification Address Verification)

Hector Santos wrote:

> I did learn one new trick that I think I will implement and
> explore - flip it around, test the random address first.
> If accept, it is operating in an open relay behavior.
It could be also a "teergrube" accepting one character per
second after DATA (with a 5xx after the data).  You're not
testing a dummy (empty) DATA, or are you ?  I report this
crap as spam.
                        Bye, Frank