Lars Vogdt wrote:
Today I got an emergency call from our security team: their mailing list was "spammed" from a bot (aka ticket system) - as the ticket system address (which looks it was in CC of one Email to the list) generated an Email to the list - getting an answer from mlmmj that it is not subscribed, which generated a new ticket with an automated answer, which was answered by mlmmj... (I think you got the loop)
Still getting some of them trickling through :-)
As result, I created /etc/postfix/sender_access with : $EMAIL DROP inside,
There is no DROP action for sender access, REJECT would probably be better. I
think DROP led to "451 4.3.5 Server configuration error; from=