Provided by: fail2ban_0.11.2-6_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: INFO  (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  parse  a  common part containing in every
              message (see prefregex in section FILTER FILES for details).

              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.  Multiple  systemd-specific  flags can be passed to the
              backend, including journalpath and journalfiles, to explicitly set the  path  to  a
              directory  or  set  of files. journalflags, which by default is 4 and excludes user
              session files, can be set to include them  with  journalflags=1,  see  the  python-
              systemd documentation for other settings and further details. Examples:

              backend = systemd[journalpath=/run/log/journal/machine-1]
              backend = systemd[journalfiles="/path/to/system.journal, /path/to/user.journal"]
              backend = systemd[journalflags=1]

       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 several standard filter definitions used in the [Definition] section:

              is  the  regex  (regular  expression)  to  parse  a common part containing in every
              message, which is applied after datepattern found a match, before  the  search  for
              any failregex or ignoreregex would start.
              If  this  regex doesn't match the process is starting immediately with next message
              and search for any failregex does not occur.
              If prefregex contains <F-CONTENT>...</F-CONTENT>,  the  part  of  message  enclosed
              between  this  tags will be extracted and herafter used as whole message for search
              with failregex or ignoreregex.

              For example:
                      prefregex = ^%(__prefix_line)s (?:ERROR|FAILURE) <F-CONTENT>.+</F-CONTENT>$
                      failregex = ^user not found
                                  ^authentication failed
                                  ^unknown authentication method

              You can use prefregex in order to:

                     - specify 1 common regex to match some common part present in every messages
                     (do avoid unneeded match in every failregex if you have more as one);

                     -  to  cut  some  interesting  part  of message only (to simplify failregex)
                     enclosed between tags <F-CONTENT> and </F-CONTENT>;

                     - to gather some failure identifier  (e.  g.  some  prefix  matched  by  <F-
                     MLFID>...<F-MLFID/>  tag)  to  identify  several  messages belonging to same
                     session,  where  a  connect  message  containing  IP  followed  by   failure
                     message(s)  that  are not contain IP; this provides a new multi-line parsing
                     method as replacement for  old  (slow  an  ugly)  multi-line  parsing  using
                     buffering window (maxlines > 1 and <SKIPLINES>);

                     -  to ignore some wrong, too long or even unneeded messages (a.k.a. parasite
                     log traffic) which can be also present in journal, before  failregex  search
                     would take place.

              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).

              NOTE: the failregex will  be  applied  to  the  remaining  part  of  message  after
              prefregex  processing  (if  specified), which in turn takes place after datepattern
              processing (whereby the string of timestamp matching the best pattern, cut out from
              the message).

              For multiline regexs (parsing with maxlines greater that 1) the tag <SKIPLINES> can
              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.
              This  is  an  obsolete  handling  and  if the lines contain some common identifier,
              better would be to use new handling (with tags <F-MLFID>...<F-MLFID/>).

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

              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.
              NOTE:  due  to config file string substitution, that %'s must be escaped by an % in
              config files.
              Also, special values of Epoch (UNIX Timestamp), TAI64N and ISO8601 can be  used  as
              Normally  the  regexp  generated  for  datepattern additionally gets word-start and
              word-end boundaries to avoid accidental match inside of some  word  in  a  message.
              There  are  several prefixes and words with special meaning that could be specified
              with custom datepattern to control resulting regex:

                     {DEFAULT} - can be used to add default date patterns of fail2ban.

                     {DATE} - can be used as part of regex that will  be  replaced  with  default
                     date patterns.

                     {^LN-BEG} - prefix (similar to ^) changing word-start boundary to line-start
                     boundary (ignoring up to 2 characters). If used as value (not as a  prefix),
                     it  will  also  set  all  default  date patterns (similar to {DEFAULT}), but
                     anchored at begin of message line.

                     {UNB} - prefix to disable automatic word boundaries in regex.

                     {NONE} - value would allow to find failures totally without date-time in log
                     message.  Filter  will  use now as a timestamp (or last known timestamp from
                     previous line with timestamp).

              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, filters may have an [Init] section also (optional since  v.0.10).  All
       parameters  of  both  sections  [Definition]  and  [Init]  can be overridden (redefined or
       extended) in jail.conf or jail.local (or in  related  filter.d/filter-name.local).   Every
       option  supplied  in  the  jail  to  the  filter  overwrites the value specified in [Init]
       section, which in turm would overwrite the value in  [Definition]  section.   Besides  the
       standard  settings  of  filter  both  sections  can  be used to initialize filter-specific

       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