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