Otherwise, postfwd and the like could be configured for a rate limit
of zero (can't send mail).
Sorry, for the late answer, but no zero rate limits are required here.
With postfwd simply use:
id=SASLDROP
sasl_username==barrak
sasl_username==vladimir
sasl_username==mao
action=REJECT sorry no access for user $$sasl_username
It is also possible to have a separate file with the sasl_usernames:
id=SASLDROP
sasl_username==file:/etc/postfwd/evil_users
action=REJECT sorry no access for user $$sasl_username
Jan
