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File name : sendmail-reject.conf

Content :# Fail2Ban filter for sendmail spam/relay type failures # # Some of the below failregex will only work properly, when the following # options are set in the .mc file (see your Sendmail documentation on how # to modify it and generate the corresponding .cf file): # # FEATURE(`delay_checks') # FEATURE(`greet_pause', `500') # FEATURE(`ratecontrol', `nodelay', `terminate') # FEATURE(`conncontrol', `nodelay', `terminate') # # ratecontrol and conncontrol also need corresponding options ClientRate: # and ClientConn: in the access file, see documentation for ratecontrol and # conncontrol in the sendmail/cf/README file. [INCLUDES] before = common.conf [Definition] _daemon = (?:(sm-(mta|acceptingconnections)|sendmail)) __prefix_line = %(known/__prefix_line)s(?:\w{14,20}: )? prefregex = ^<F-MLFID>%(__prefix_line)s</F-MLFID><F-CONTENT>.+</F-CONTENT>$ cmnfailre = ^ruleset=check_rcpt, arg1=(?P<email><\S+@\S+>), relay=(\S+ )?\[(?:IPv6:<IP6>|<IP4>)\](?: \(may be forged\))?, reject=(550 5\.7\.1 (?P=email)\.\.\. Relaying denied\. (IP name possibly forged \[(\d+\.){3}\d+\]|Proper authentication required\.|IP name lookup failed \[(\d+\.){3}\d+\])|553 5\.1\.8 (?P=email)\.\.\. Domain of sender address \S+ does not exist|550 5\.[71]\.1 (?P=email)\.\.\. (Rejected: .*|User unknown))$ ^ruleset=check_relay, arg1=(?P<dom>\S+), arg2=(?:IPv6:<IP6>|<IP4>), relay=((?P=dom) )?\[(\d+\.){3}\d+\](?: \(may be forged\))?, reject=421 4\.3\.2 (Connection rate limit exceeded\.|Too many open connections\.)$ ^rejecting commands from (\S* )?\[(?:IPv6:<IP6>|<IP4>)\] due to pre-greeting traffic after \d+ seconds$ ^(?:\S+ )?\[(?:IPv6:<IP6>|<IP4>)\]: (?:(?i)expn|vrfy) \S+ \[rejected\]$ ^<[^@]+@[^>]+>\.\.\. No such user here$ ^<F-NOFAIL>from=<[^@]+@[^>]+></F-NOFAIL>, size=\d+, class=\d+, nrcpts=\d+, bodytype=\w+, proto=E?SMTP, daemon=MTA, relay=\S+ \[(?:IPv6:<IP6>|<IP4>)\]$ mdre-normal = mdre-extra = ^(?:\S+ )?\[(?:IPv6:<IP6>|<IP4>)\](?: \(may be forged\))? did not issue (?:[A-Z]{4}[/ ]?)+during connection to (?:TLS)?M(?:TA|S[PA])(?:-\w+)?$ mdre-aggressive = %(mdre-extra)s failregex = %(cmnfailre)s <mdre-<mode>> # Parameter "mode": normal (default), extra or aggressive # Usage example (for jail.local): # [sendmail-reject] # filter = sendmail-reject[mode=extra] # mode = normal ignoreregex = journalmatch = SYSLOG_IDENTIFIER=sm-mta + _SYSTEMD_UNIT=sendmail.service # DEV NOTES: # # Regarding the multiline regex: # # "No such user" lines generate a failure and needs to be matched together with # another line with the HOST, therefore no-failure line was added as regex, that # contains HOST (see line with tag <F-NOFAIL>). # # Note the capture <F-MLFID>, includes both the __prefix_lines (which includes # the sendmail PID), but also the `\w{14}` which the the sendmail assigned # mail ID (todo: check this is necessary, possible obsolete). # # Author: Daniel Black, Fabian Wenk and Sergey Brester aka sebres. # Rewritten using prefregex by Serg G. Brester.

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