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jail.conf(10) - phpMan
JAIL.CONF(10) Fail2Ban Configuration JAIL.CONF(10)
NAME
jail.conf - configuration for the fail2ban server
SYNOPSIS
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
filter.d/*.conf filter.d/*.local
DESCRIPTION
Fail2ban has four configuration file types:
fail2ban.conf
Fail2Ban global configuration (such as logging)
filter.d/*.conf
Filters specifying how to detect authentication failures
action.d/*.conf
Actions defining the commands for banning and unbanning of IP address
jail.conf
Jails defining combinations of Filters with Actions.
CONFIGURATION FILES FORMAT
*.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
jail.local
[ssh-iptables-ipset]
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 corre‐
sponding .d/ directory containing additional .conf files. The order e.g. for jail
configuration would be:
jail.conf
jail.d/*.conf (in alphabetical order)
jail.local
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 prece‐
dence over identical entries in previously parsed files. Files are ordered alpha‐
betically, 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. For example.
baduseragents = IE|wget
failregex = useragent=%(baduseragents)s
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 bug.
FAIL2BAN CONFIGURATION FILE(S) (fail2ban.conf)
These files have one section, [Definition].
The items that can be set are:
loglevel
verbosity level of log output: 1 = ERROR, 2 = WARN, 3 = INFO, 4 = DEBUG. Default: 1
logtarget
log target: filename, SYSLOG, STDERR or STDOUT. Default: STDERR . 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 config‐
uration file (e.g. /etc/logrotate.d/fail2ban on Debian systems).
socket socket filename. Default: /var/run/fail2ban/fail2ban.sock . This is used for com‐
munication 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.
pidfile
PID filename. Default: /var/run/fail2ban/fail2ban.pid. This is used to store the
process ID of the fail2ban server.
JAIL CONFIGURATION FILE(S) (jail.conf)
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 spec‐
ified 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.
logpath
filename(s) of the log files to be monitored. 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.
Ensure syslog or the program that generates the log file isn't configured to com‐
press 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 Off.
action action(s) from /etc/fail2ban/action.d/ without the .conf/.local extension. Argu‐
ments can be passed to actions to override the default values from the [Init] sec‐
tion in the action file. Arguments are specified by:
[name=value,name2=value,name3="values,values"]
Values can also be quoted (required when value includes a ","). More that one
action can be specified (in separate lines).
ignoreip
list of IPs not to ban. They can include a CIDR mask too.
ignorecommand
command that is executed to determine if the current candidate IP for banning
should not be banned. IP will not be banned if command returns successfully (exit
code 0). Like ACTION FILES, tags like <ip> are can be included in the ignorecom‐
mand value and will be substituted before execution. Currently only <ip> is sup‐
ported however more will be added later.
bantime
effective ban duration (in seconds).
findtime
time interval (in seconds) before the current time where failures will count
towards a ban.
maxretry
number of failures that have to occur in the last findtime seconds to ban then IP.
backend
backend to be used to detect changes in the logpath. It defaults to "auto" which
will try "pyinotify", "gamin" before "polling". Any of these can be specified.
"pyinotify" is only valid on Linux systems with the "pyinotify" Python libraries.
"gamin" requires the "gamin" libraries.
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 res‐
olution altogether (thus ignoring entries where hostname, not an IP is logged)..
failregex
regex (Python regular expression) to be added to the filter's failregexes. 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).
ignoreregex
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
filters.
ACTION CONFIGURATION FILES (action.d/*.conf)
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.
actionstart
command(s) executed when the jail starts.
actionstop
command(s) executed when the jail stops.
actioncheck
command(s) ran before any other action. It aims to verify if the environment is
still ok.
actionban
command(s) that bans the IP address after maxretry log lines matches within last
findtime seconds.
actionunban
command(s) that unbans the IP address after bantime.
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 setctag 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 sepa‐
rate 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. 192.168.0.2
failures
number of times the failure occurred in the log file. e.g. 3
time UNIX (epoch) time of the ban. e.g. 1357508484
matches
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.
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] sec‐
tion.
There are two filter definitions used in the [Definition] section:
failregex
regex that will match failed attempts. The tag <HOST> is used as part of the regex
and is itself a regex for IPv4 addresses (and hostnames if usedns). Fail2Ban will
work out which one of these it actually is.
ignoreregex
regex to identify log entries that should be ignored by Fail2Ban, even if they
match failregex.
AUTHOR
Fail2ban was originally written by Cyril Jaquier <cyril.jaquier AT fail2ban.org>. At the
moment it is maintained and further developed by Yaroslav O. Halchenko <debian@onerus‐
sian.com>, Daniel Black <daniel.subs AT internode.net> and Steven Hiscocks <steven-
fail2ban AT hiscocks.uk> along with a number of contributors. See THANKS file shipped
with Fail2Ban for a full list. Manual page written by Daniel Black and Yaroslav
Halchenko.
REPORTING BUGS
Report bugs to https://github.com/fail2ban/fail2ban/issues
COPYRIGHT
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 ver‐
sion.
SEE ALSO
fail2ban-server(1)
Fail2Ban October 2013 JAIL.CONF(10)
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