[Postfix]: Block Spam with Helo Restrictions

/etc/postfix/main.cf:

###Block HELO Wildcards
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, check_helo_access hash:/etc/postfix/helo_access, permit

Example Syntax for mailminion:

/etc/postfix/helo_access:

.mailminion.net REJECT Fuck off - I hate spam like this!
mailminion.net REJECT Fuck off - I hate spam like this!
mmsvr.net REJECT Fuck off - I hate spam like this!
.mmsvr.net REJECT Fuck off - I hate spam like this!

Build readable database for postfix:

postmap helo_access

Restart Postfix:

/etc/init.d/postfix restart
or
service postfix restart

~Faulwurf