On Mar 25, 2009, at 8:14 AM, frantisek holop wrote:
hmm, on Wed, Mar 25, 2009 at 03:40:09PM +0100, Gilles Chehade said
that
Are you sure ?
just because you demonstrated a smtp session with
a questionably set up mail server it doesn't mean
you are right. sendmail by default does not check helo.
/etc/postfix/main.cf:
smtpd_helo_required = yes
smtpd_helo_restrictions =
reject_invalid_hostname
reject_unknown_hostname
reject_non_fqdn_hostname
these settings save any server a ton of work by not allowing
made up and incorrect helo's, one of the most reliable sign
of spam and clueless admins in general.
The amount of connections rejected by those settings will be pretty
small as a percentage, and it's not even close to "reliable sign of
spam". There are way more clueless admins than clued, but
unfortunately a lot of them send completely legitimate mail. How do I
know? I've worked at e-mail hosting and/or e-mail security companies
for the last 10 years. You're wrong.
--
bk
