2013-05-13 03:56:05 UTC
Since I started using mailing-lists, my inbox has been attacked with
spam. At first it was not so bad, but now its ridiculous and I have to act.
I am currently looking at using the 'smtpd_helo_required' parameter in
my main/cf configuration file.
I am someone that won't use a spam prevention method that could block a
a legitimate e-mail, and as so, my way of fighting spam is by
protocol-compliance means only.
I wasn't sure if 'smtpd_helo_required' was suitable as I wasn't sure if
the SMTP 'HELO' message was a protocol requirement. After reading
'220.127.116.11 Extended HELLO (EHLO) or HELLO (HELO)' of RFC 2821, I learnt
that it is a protocol requirement.
As HELO is a requirement of the SMTP specification, then the parameter
'smtpd_helo_required' should not exist, and Postfix should not accept
e-mail if the remote server does not send a HELO message, period.