fail2ban/config/filter.d/postfix.conf

# Fail2Ban filter for selected Postfix SMTP rejections
#
#

[INCLUDES]

# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf

[Definition]

_daemon = postfix(-\w+)?/(?:submission/|smtps/)?smtp[ds]

prefregex = ^%(__prefix_line)s(?:NOQUEUE: reject:|improper command pipelining) <F-CONTENT>.+</F-CONTENT>$

failregex = ^RCPT from \S+\[<HOST>\]: 554 5\.7\.1 
            ^RCPT from \S+\[<HOST>\]: 450 4\.7\.1 Client host rejected: cannot find your (reverse )?hostname\b
            ^RCPT from \S+\[<HOST>\]: 450 4\.7\.1 (<[^>]*>)?: Helo command rejected: Host not found\b
            ^EHLO from \S+\[<HOST>\]: 504 5\.5\.2 (<[^>]*>)?: Helo command rejected: need fully-qualified hostname\b
            ^VRFY from \S+\[<HOST>\]: 550 5\.1\.1 
            ^RCPT from \S+\[<HOST>\]: 450 4\.1\.8 (<[^>]*>)?: Sender address rejected: Domain not found\b
            ^after \S+ from [^[]*\[<HOST>\]:?

ignoreregex = 

[Init]

journalmatch = _SYSTEMD_UNIT=postfix.service

# Author: Cyril Jaquier