I was wondering, how many legitimate email (i.e. poorly configured but legit
MTA’s out there) would be blocked with either of these?
unknown_client_reject_code = 550 # Hmm, should this be another value in the 5xx
range?
smtpd_recipient_restrictions =
…,
reject_unknown_client_hostname
...
unknown_hostname_reject_code = 550 # Hmm, should this be another value in the
5xx range?
smtpd_helo_restrictions =
…,
reject_unknown_helo_hostname,
…
I personally suspect that the reject_unknown_client_hostname would block too
much, but the reject_unknown_helo_hostname would be ok. Am I right?
I’d like to turn this on against spam, but I don’t want to lose legit mail.
G
