Edit File: 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+)?/\w+(?:/smtp[ds])? _port = (?::\d+)? _pref = [A-Z]{4} prefregex = ^%(__prefix_line)s<mdpr-<mode>> <F-CONTENT>.+</F-CONTENT>$ # Extended RE for normal mode to match reject by unknown users or undeliverable address, can be set to empty to avoid this: exre-user = |[Uu](?:ser unknown|ndeliverable address) mdpr-normal = (?:\w+: (?:milter-)?reject:|(?:improper command pipelining|too many errors) after \S+) mdre-normal=^%(_pref)s from [^[]*\[<HOST>\]%(_port)s: [45][50][04] [45]\.\d\.\d+ (?:(?:<[^>]*>)?: )?(?:(?:Helo command|(?:Sender|Recipient) address) rejected: )?(?:Service unavailable|(?:Client host|Command|Data command) rejected|Relay access denied|(?:Host|Domain) not found|need fully-qualified hostname|match%(exre-user)s)\b ^from [^[]*\[<HOST>\]%(_port)s:? mdpr-auth = warning: mdre-auth = ^[^[]*\[<HOST>\]%(_port)s: SASL ((?i)LOGIN|PLAIN|(?:CRAM|DIGEST)-MD5) authentication failed:(?! Connection lost to authentication server| Invalid authentication mechanism) mdre-auth2= ^[^[]*\[<HOST>\]%(_port)s: SASL ((?i)LOGIN|PLAIN|(?:CRAM|DIGEST)-MD5) authentication failed:(?! Connection lost to authentication server) # todo: check/remove "Invalid authentication mechanism" from ignore list, if gh-1243 will get finished (see gh-1297). # Mode "rbl" currently included in mode "normal", but if needed for jail "postfix-rbl" only: mdpr-rbl = %(mdpr-normal)s mdre-rbl = ^%(_pref)s from [^[]*\[<HOST>\]%(_port)s: [45]54 [45]\.7\.1 Service unavailable; Client host \[\S+\] blocked\b # Mode "rbl" currently included in mode "normal" (within 1st rule) mdpr-more = %(mdpr-normal)s mdre-more = %(mdre-normal)s # Includes some of the log messages described in # <http://www.postfix.org/POSTSCREEN_README.html>. mdpr-ddos = (?:lost connection after(?! DATA) [A-Z]+|disconnect(?= from \S+(?: \S+=\d+)* auth=0/(?:[1-9]|\d\d+))|(?:PREGREET \d+|HANGUP) after \S+|COMMAND (?:TIME|COUNT|LENGTH) LIMIT) mdre-ddos = ^from [^[]*\[<HOST>\]%(_port)s:? mdpr-extra = (?:%(mdpr-auth)s|%(mdpr-normal)s) mdre-extra = %(mdre-auth)s %(mdre-normal)s mdpr-aggressive = (?:%(mdpr-auth)s|%(mdpr-normal)s|%(mdpr-ddos)s) mdre-aggressive = %(mdre-auth2)s %(mdre-normal)s mdpr-errors = too many errors after \S+ mdre-errors = ^from [^[]*\[<HOST>\]%(_port)s$ failregex = <mdre-<mode>> # Parameter "mode": more (default combines normal and rbl), auth, normal, rbl, ddos, extra or aggressive (combines all) # Usage example (for jail.local): # [postfix] # mode = aggressive # # # or another jail (rewrite filter parameters of jail): # [postfix-rbl] # filter = postfix[mode=rbl] # # # jail to match "too many errors", related postconf `smtpd_hard_error_limit`: # # (normally included in other modes (normal, more, extra, aggressive), but this jail'd allow to ban on the first message) # [postfix-many-errors] # filter = postfix[mode=errors] # maxretry = 1 # mode = more ignoreregex = [Init] journalmatch = _SYSTEMD_UNIT=postfix.service # Author: Cyril Jaquier