fail2ban/config/filter.d/sendmail-auth.conf

# Fail2Ban filter for sendmail authentication failures
#

[INCLUDES]

before = common.conf

[Definition]

_daemon = (?:sendmail|sm-(?:mta|acceptingconnections))
__prefix_line = %(known/__prefix_line)s(?:\w{14,20}: )?

# "w{14,20}" will give support for IDs from 14 up to 20 characters long
failregex = ^%(__prefix_line)s(\S+ )?\[(?:IPv6:<IP6>|<IP4>)\]( \(may be forged\))?: possible SMTP attack: command=AUTH, count=\d+$

ignoreregex =

journalmatch = _SYSTEMD_UNIT=sendmail.service

# DEV Notes:
#
# Author: Daniel Black