[Mimedefang] "Possible SMTP attack: command=HELO/EHLO, count=3"

[Joseph Brennan]

Yesterday we had 57,510 of these from 29,312 different IP addresses.
Therefore they average less than 2 a day per IP.

Many were to invalid addresses, some of them in a format that could
never have been a valid address in our domain.  From a few that were
to valid addresses, and so had subject logged-- prescription drug spam.

Joseph Brennan
Lead Email Systems Engineer
Columbia University Information Technology