Provided by: fail2ban_0.11.1-1_all bug


       jail.conf - configuration for the fail2ban server


       fail2ban.conf fail2ban.d/*.conf fail2ban.local fail2ban.d/*.local

       jail.conf jail.d/*.conf jail.local jail.d/*.local

       action.d/*.conf action.d/*.local action.d/*.py

       filter.d/*.conf filter.d/*.local


       Fail2ban has four configuration file types:

              Fail2Ban global configuration (such as logging)

              Filters specifying how to detect authentication failures

              Actions defining the commands for banning and unbanning of IP address

              Jails defining combinations of Filters with Actions.


       *.conf  files  are  distributed  by  Fail2Ban.  It is recommended that *.conf files should
       remain unchanged to ease upgrades.   If  needed,  customizations  should  be  provided  in
       *.local  files.   For  example,  if you would like to enable the [ssh-iptables-ipset] jail
       specified in jail.conf, create jail.local containing


              enabled = true

       In .local files specify only the settings you would like to change and  the  rest  of  the
       configuration will then come from the corresponding .conf file which is parsed first.

       jail.d/ and fail2ban.d/

              In  addition  to  .local,  for  jail.conf  or  fail2ban.conf  file  there  can be a
              corresponding .d/ directory containing additional .conf files. The order  e.g.  for
              jail configuration would be:

              jail.d/*.conf (in alphabetical order)
              jail.d/*.local (in alphabetical order).

              i.e.  all  .local  files are parsed after .conf files in the original configuration
              file and files under  .d  directory.   Settings  in  the  file  parsed  later  take
              precedence  over  identical  entries in previously parsed files.  Files are ordered
              alphabetically, e.g.

              fail2ban.d/01_custom_log.conf - to use a different log path
              jail.d/01_enable.conf - to enable a specific jail
              jail.d/02_custom_port.conf - to change the port(s) of a jail.

       Configuration files have sections, those specified with [section name], and name  =  value
       pairs.  For those name items that can accept multiple values, specify the values separated
       by spaces, or in separate lines space indented at the beginning of  the  line  before  the
       second value.

       Configuration  files  can  include  other (defining common variables) configuration files,
       which is often used in Filters and Actions. Such  inclusions  are  defined  in  a  section
       called [INCLUDES]:

       before indicates that the specified file is to be parsed before the current file.

       after  indicates that the specified file is to be parsed after the current file.

       Using  Python  "string  interpolation"  mechanisms,  other definitions are allowed and can
       later be used within other definitions as %(name)s.

       Fail2ban has more advanced syntax (similar python extended interpolation).  This  extended
       interpolation is using %(section/parameter)s to denote a value from a foreign section.
       Besides  cross  section  interpolation  the value of parameter in [DEFAULT] section can be
       retrieved with %(default/parameter)s.
       Fail2ban supports also another feature named %(known/parameter)s (means last known  option
       with  name  parameter). This interpolation makes possible to extend a stock filter or jail
       regexp in .local file (opposite to simply set failregex/ignoreregex that  overwrites  it),

              baduseragents = IE|wget|%(my-settings/baduseragents)s
              failregex = %(known/failregex)s

       Additionally  to  interpolation %(known/parameter)s, that does not works for filter/action
       init parameters, an interpolation tag <known/parameter> can be used (means last known init
       definition  of  filters or actions with name parameter). This interpolation makes possible
       to  extend  a  parameters  of  stock  filter   or   action   directly   in   jail   inside
       jail.conf/jail.local file without creating a separately filter.d/*.local file, e.g.

              # filter.d/test.conf:
              test.method = GET
              baduseragents = IE|wget
              failregex = ^%(__prefix_line)\s+"<test.method>"\s+test\s+regexp\s+-\s+useragent=(?:<baduseragents>)

              # jail.local:
              # use filter "test", overwrite method to "POST" and extend known bad agents with "badagent":
              filter = test[test.method=POST, baduseragents="badagent|<known/baduseragents>"]

       Comments:  use  '#'  for  comment lines and '; ' (space is important) for inline comments.
       When using Python2.X, '; ' can only be used on the first line due  to  an  Python  library


       The items that can be set in section [Definition] are:

              verbosity  level  of  log  output:  CRITICAL,  ERROR, WARNING, NOTICE, INFO, DEBUG,
              TRACEDEBUG, HEAVYDEBUG or corresponding numeric value (50-5). Default: ERROR (equal

              log  target:  filename,  SYSLOG,  STDERR  or  STDOUT. Default: STDOUT if not set in
              Note. If fail2ban running as systemd-service, for logging to  the  systemd-journal,
              the logtarget could be set to STDOUT
              Only  a  single  log  target  can  be  specified.  If you change logtarget from the
              default value and you are using logrotate -- also adjust or disable rotation in the
              corresponding   configuration   file   (e.g.  /etc/logrotate.d/fail2ban  on  Debian

       socket socket filename.  Default: /var/run/fail2ban/fail2ban.sock
              This is used for communication with the fail2ban server daemon. Do not remove  this
              file  when  Fail2ban  is  running.  It will not be possible to communicate with the
              server afterwards.

              PID filename.  Default: /var/run/fail2ban/
              This is used to store the process ID of the fail2ban server.

       dbfile Database filename. Default: /var/lib/fail2ban/fail2ban.sqlite3
              This defines where the persistent data for fail2ban is stored. This persistent data
              allows  bans  to  be  reinstated  and continue reading log files from the last read
              position when fail2ban is restarted. A value of None disables this feature.

              Max number of matches stored in database per ticket. Default: 10
              This option sets the max number of matched log-lines could be stored per ticket  in
              the  database.  This  also  affects  values  resolvable  via  tags  <ipmatches> and
              <ipjailmatches> in actions.

              Database purge age in seconds. Default: 86400 (24hours)
              This sets the age at which bans should be purged from the database.

       The config parameters of section [Thread] are:

              Stack size of each thread in fail2ban. Default: 0 (platform or configured default)
              This specifies the stack size (in KiB) to be used for subsequently created threads,
              and must be 0 or a positive integer value of at least 32.


       The  following options are applicable to any jail. They appear in a section specifying the
       jail name or in the [DEFAULT] section which defines default  values  to  be  used  if  not
       specified in the individual section.

       filter name of the filter -- filename of the filter in /etc/fail2ban/filter.d/ without the
              .conf/.local extension.
              Only one filter can be specified.

              filename(s) of the log files to be monitored, separated by new lines.
              Globs -- paths containing * and ? or [0-9] -- can be used however  only  the  files
              that exist at start up matching this glob pattern will be considered.

              Optional space separated option 'tail' can be added to the end of the path to cause
              the log file to be read from the end, else default 'head' option  reads  file  from
              the beginning

              Ensure  syslog  or  the  program  that  generates  the log file isn't configured to
              compress repeated log messages to "*last message repeated 5  time*s"  otherwise  it
              will  fail  to detect. This is called RepeatedMsgReduction in rsyslog and should be

              encoding of log files used for decoding.  Default  value  of  "auto"  uses  current
              system locale.

              Force the time zone for log lines that don't have one.

              If  this  option  is  not specified, log lines from which no explicit time zone has
              been found are interpreted by fail2ban in its own system time zone,  and  that  may
              turn  to  be  inappropriate.  While the best practice is to configure the monitored
              applications to include explicit offsets, this option  is  meant  to  handle  cases
              where that is not possible.

              The supported time zones in this option are those with fixed offset: Z, UTC[+-]hhmm
              (you can also use GMT as an alias to UTC).

              This option has no effect on log lines on which an  explicit  time  zone  has  been
              found.  Examples:

                      logtimezone = UTC
                      logtimezone = UTC+0200
                      logtimezone = GMT-0100

              banning  action  (default  iptables-multiport) typically specified in the [DEFAULT]
              section for all jails.
              This parameter will be used by the standard  substitution  of  action  and  can  be
              redefined  central  in  the [DEFAULT] section inside jail.local (to apply it to all
              jails at once) or separately in each jail, where this substitution will be used.

              the same  as  banaction  but  for  some  "allports"  jails  like  "pam-generic"  or
              "recidive" (default iptables-allports).

       action action(s) from /etc/fail2ban/action.d/ without the .conf/.local extension.
              Arguments  can  be passed to actions to override the default values from the [Init]
              section in the action file. Arguments are specified by:


              Values can also be quoted (required when value  includes  a  ",").  More  that  one
              action can be specified (in separate lines).

              boolean  value  (default  true) indicates the banning of own IP addresses should be

              list of IPs not to ban. They can include a DNS resp.  CIDR  mask  too.  The  option
              affects  additionally  to  ignoreself  (if  true) and don't need to contain own DNS
              resp. IPs of the running host.

              command that is executed to determine if the current candidate IP for  banning  (or
              failure-ID  for  raw  IDs) should not be banned. The option affects additionally to
              ignoreself and ignoreip and will be first executed if both don't hit.
              IP will not be banned if command returns successfully (exit code 0).   Like  ACTION
              FILES,  tags  like  <ip> are can be included in the ignorecommand value and will be
              substituted before execution.

              provide cache parameters (default disabled) for ignore failure  check  (caching  of
              the result from `ignoreip`, `ignoreself` and `ignorecommand`), syntax:

                      ignorecache = key="<F-USER>@<ip-host>", max-count=100, max-time=5m
                      ignorecommand = if [ "<F-USER>" = "technical" ] && [ "<ip-host>" = "" ]; then exit 0; fi;
                                      exit 1
              This  will  cache  the  result of ignorecommand (does not call it repeatedly) for 5
              minutes (cache time) for maximal 100 entries (cache size), using values substituted
              like "user@host" as cache-keys.  Set option ignorecache to empty value disables the

              effective ban duration (in seconds or time abbreviation format).

              time interval (in seconds or time abbreviation  format)  before  the  current  time
              where failures will count towards a ban.

              number of failures that have to occur in the last findtime seconds to ban then IP.

              backend to be used to detect changes in the logpath.
              It  defaults  to  "auto"  which  will  try  "pyinotify",  "gamin", "systemd" before
              "polling". Any of these can be  specified.  "pyinotify"  is  only  valid  on  Linux
              systems  with  the  "pyinotify"  Python  libraries.  "gamin"  requires  the "gamin"

       usedns use DNS to resolve HOST names that appear in the logs.  By  default  it  is  "warn"
              which  will resolve hostnames to IPs however it will also log a warning. If you are
              using DNS here you could be blocking the wrong IPs due to the asymmetric nature  of
              reverse DNS (that the application used to write the domain name to log) compared to
              forward DNS that fail2ban uses to resolve this back to an IP (but  not  necessarily
              the  same  one).  Ideally  you should configure your applications to log a real IP.
              This can be set to "yes" to prevent warnings in the log  or  "no"  to  disable  DNS
              resolution altogether (thus ignoring entries where hostname, not an IP is logged)..

              regex  (Python  regular  expression)  to  be added to the filter's failregexes (see
              failregex in section FILTER FILES for details). If this is useful for others  using
              your  application  please share you regular expression with the fail2ban developers
              by reporting an issue (see REPORTING BUGS below).

              regex which, if the log line matches, would cause Fail2Ban not consider that  line.
              This  line will be ignored even if it matches a failregex of the jail or any of its

              max number of matched log-lines the jail  would  hold  in  memory  per  ticket.  By
              default  it  is  the same value as maxretry of jail (or default).  This option also
              affects values resolvable via tag <matches> in actions.

       Available options are listed below.

              requires pyinotify (a file alteration monitor) to be installed. If pyinotify is not
              installed, Fail2ban will use auto.

       gamin  requires  Gamin  (a  file  alteration  monitor)  to  be  installed. If Gamin is not
              installed, Fail2ban will use auto.

              uses a polling algorithm which does not require external libraries.

              uses systemd python library to access the systemd journal.  Specifying  logpath  is
              not  valid  for  this  backend  and  instead  utilises  journalmatch from the jails
              associated filter config.

       Each jail can be configured with only a single filter, but may have multiple  actions.  By
       default,  the  name of a action is the action filename, and in the case of Python actions,
       the ".py" file extension is stripped. Where multiple of the same action are  to  be  used,
       the actname option can be assigned to the action to avoid duplication e.g.:

       enabled = true
       action =[, actname=smtp-chris]
      [, actname=smtp-sally]


       The  time  entries in fail2ban configuration (like findtime or bantime) can be provided as
       integer in seconds or as string using special abbreviation format (e. g. 600 is  the  same
       as 10m).

       Abbreviation tokens:

              years?, yea?, yy?
              months?, mon?
              weeks?, wee?, ww?
              days?, da, dd?
              hours?, hou?, hh?
              minutes?, min?, mm?
              seconds?, sec?, ss?

              The question mark (?) means the optional character, so day as well as days can be used.

       You  can combine multiple tokens in format (separated with space resp. without separator),
       e. g.: 1y 6mo or 1d12h30m.
       Note that tokens m as well as mm means minutes, for month use abbreviation mo or mon.

       The time format can be tested using fail2ban-client:

              fail2ban-client --str2sec 1d12h


       Action files specify which commands are executed to ban and unban an IP address.

       Like with jail.conf files, if you desire local changes create an  [actionname].local  file
       in the /etc/fail2ban/action.d directory and override the required settings.

       Action files have two sections, Definition and Init .

       The  [Init] section enables action-specific settings. In jail.conf/jail.local these can be
       overridden for a particular jail as options of the action's specification in that jail.

       The following commands can be present in the [Definition] section.

              command(s) executed when the jail starts.

              command(s) executed when the jail stops.

              command(s) ran before any other action. It aims to verify  if  the  environment  is
              still ok.

              command(s)  that  bans  the IP address after maxretry log lines matches within last
              findtime seconds.

              command(s) that unbans the IP address after bantime.

       The [Init] section allows for action-specific settings. In jail.conf/jail.local these  can
       be  overwritten  for  a  particular jail as options to the jail. The following are special
       tags which can be set in the [Init] section:

              The maximum period of time in seconds that a command  can  executed,  before  being

       Commands  specified  in  the  [Definition]  section are executed through a system shell so
       shell redirection and process control is allowed. The commands should return 0,  otherwise
       error  would  be  logged.  Moreover if actioncheck exits with non-0 status, it is taken as
       indication that firewall status has changed and  fail2ban  needs  to  reinitialize  itself
       (i.e.  issue  actionstop  and  actionstart  commands).   Tags are enclosed in <>.  All the
       elements of [Init] are tags that are replaced in all action commands.  Tags can  be  added
       by  the fail2ban-client using the "set <JAIL> action <ACT>" command. <br> is a tag that is
       always a new line (\n).

       More than a single command is allowed to be specified. Each  command  needs  to  be  on  a
       separate  line  and indented with whitespace(s) without blank lines. The following example
       defines two commands to be executed.

        actionban = iptables -I fail2ban-<name> --source <ip> -j DROP
                    echo ip=<ip>, match=<match>, time=<time> >> /var/log/fail2ban.log

   Action Tags
       The following tags are substituted in the actionban,  actionunban  and  actioncheck  (when
       called before actionban/actionunban) commands.

       ip     IPv4 IP address to be banned. e.g.

              number of times the failure occurred in the log file. e.g. 3

              As  per  failures,  but  total of all failures for that ip address across all jails
              from the fail2ban persistent database. Therefore the database must be set for  this
              tag to function.

              As per ipfailures, but total based on the IPs failures for the current jail.

       time   UNIX (epoch) time of the ban. e.g. 1357508484

              concatenated  string  of  the log file lines of the matches that generated the ban.
              Many characters interpreted by shell get escaped to prevent injection, nevertheless
              use with caution.

              As  per  matches,  but  includes  all lines for the IP which are contained with the
              fail2ban persistent database. Therefore the database must be set for  this  tag  to

              As per ipmatches, but matches are limited for the IP and for the current jail.


       Python  based  actions  can also be used, where the file name must be [actionname].py. The
       Python file must contain a variable Action which points to Python class. This  class  must
       implement a minimum interface as described by fail2ban.server.action.ActionBase, which can
       be inherited from to ease implementation.

FILTER FILES (filter.d/*.conf)

       Filter definitions are those in /etc/fail2ban/filter.d/*.conf and filter.d/*.local.

       These are used to identify failed authentication attempts in log files and to extract  the
       host IP address (or hostname if usedns is true).

       Like  action  files,  filter  files  are  ini  files. The main section is the [Definition]

       There are two filter definitions used in the [Definition] section:

              is the regex (regular expression) that will match  failed  attempts.  The  standard
              replacement tags can be used as part of the regex:

                     <HOST> - common regex for IP addresses and hostnames (if usedns is enabled).
                     Fail2Ban will work out which one of these it actually is.

                     <ADDR> - regex for IP addresses (both families).

                     <IP4> - regex for IPv4 addresses.

                     <IP6> - regex for IPv6 addresses (also IP enclosed in brackets).

                     <DNS> - regex to match hostnames.

                     <CIDR> - helper regex to match CIDR (simple integer form of net-mask).

                     <SUBNET> - regex to match sub-net adresses (in form of IP/CIDR, also  single
                     IP is matched, so part /CIDR is optional).

       For  multiline  regexs  the  tag <SKIPLINES> should be used to separate lines. This allows
       lines between the matched lines to continue to be searched for other failures. The tag can
       be used multiple times.

              is  the  regex  to identify log entries that should be ignored by Fail2Ban, even if
              they match failregex.

       Similar  to  actions,  filters  have  an  [Init]  section  which  can  be  overridden   in
       jail.conf/jail.local.  Besides the filter-specific settings, the filter [Init] section can
       be used to set following standard options:

              specifies the maximum number of lines to buffer to  match  multi-line  regexs.  For
              some  log  formats  this will not required to be changed. Other logs may require to
              increase this value if a particular log file is frequently written to.

              specifies a custom date  pattern/regex  as  an  alternative  to  the  default  date
              detectors  e.g.  %Y-%m-%d %H:%M(?::%S)?. For a list of valid format directives, see
              Python library documentation for strptime behaviour.
              Also, special values of Epoch (UNIX Timestamp), TAI64N and ISO8601 can be used.
              NOTE: due to config file string substitution, that %'s must be escaped by an  %  in
              config files.

              specifies  the  systemd  journal  match  used  to  filter  the journal entries. See
              journalctl(1) and systemd.journal-fields(7) for matches syntax and more details  on
              special journal fields. This option is only valid for the systemd backend.

       Similar  to  actions  [Init]  section  enables  filter-specific  settings.  All parameters
       specified in [Init] section can be redefined or extended in jail.conf/jail.local.

       Filters  can  also  have  a  section  called  [INCLUDES].  This  is  used  to  read  other
       configuration files.

       before indicates that this file is read before the [Definition] section.

       after  indicates that this file is read after the [Definition] section.


       Fail2ban  was  originally  written  by Cyril Jaquier <>.  At the
       moment   it   is   maintained   and   further   developed   by   Yaroslav   O.   Halchenko
       <>,  Daniel  Black <> and Steven Hiscocks
       <> along with a number of  contributors.   See  THANKS  file
       shipped  with  Fail2Ban for a full list.  Manual page written by Daniel Black and Yaroslav


       Report bugs to


       Copyright © 2013 the Fail2Ban Team
       Copyright of modifications held by their respective authors.
       Licensed under the GNU General Public License v2 (GPL)  or  (at  your  option)  any  later