fail2ban基于python，内置多种filter以及action，常见可对ssh voip等进行保护，原理是基于日志进行分析，自动ban掉地址。
1）filter和action是核心 需要对正则表达式以及python语法有了解才能理解，filter在jail中只能配置一个，action则可以有多个
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
2）来看下fail2ban -client -d输出：
root@ca:/etc/fail2ban# fail2ban-client -d
['set', 'syslogsocket', 'auto']
['set', 'loglevel', 'INFO']
['set', 'logtarget', '/var/log/fail2ban.log']
['set', 'dbfile', '/var/lib/fail2ban/fail2ban.sqlite3']
['set', 'dbpurgeage', 86400]
['add', 'sshd', 'auto']
['set', 'sshd', 'ignorecommand', '']
['set', 'sshd', 'addlogpath', '/var/log/auth.log', 'head']
['set', 'sshd', 'usedns', 'warn']
['set', 'sshd', 'addignoreip', '127.0.0.1/8']
['set', 'sshd', 'logencoding', 'auto']
['set', 'sshd', 'bantime', 600]
['set', 'sshd', 'maxretry', 5]
['set', 'sshd', 'findtime', 600]
['set', 'sshd', 'maxlines', '10']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?(?:error: PAM: )?[aA]uthentication (?:failure|error|failed) for .* from <HOST>( via \S+)?\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?(?:error: PAM: )?User not known to the underlying authentication module for .* from <HOST>\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?Failed \S+ for (?P<cond_inv>invalid user )?(?P<user>(?P<cond_user>\S+)|(?(cond_inv)(?:(?! from ).)*?|[^:]+)) from <HOST>(?: port \d+)?(?: ssh\d*)?(?(cond_user):|(?:(?:(?! from ).)*)$)']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?ROOT LOGIN REFUSED.* FROM <HOST>\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?[iI](?:llegal|nvalid) user .*? from <HOST>(?: port \d+)?\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?User .+ from <HOST> not allowed because not listed in AllowUsers\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?User .+ from <HOST> not allowed because listed in DenyUsers\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?User .+ from <HOST> not allowed because not in any group\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?refused connect from \S+ \(<HOST>\)\s*$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?(?:error: )?Received disconnect from <HOST>: 3: .*: Auth fail(?: \[preauth\])?$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?User .+ from <HOST> not allowed because a group is listed in DenyGroups\s*$']
['set', 'sshd', 'addfailregex', "^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?User .+ from <HOST> not allowed because none of user's groups are listed in AllowGroups\s*$"]
['set', 'sshd', 'addfailregex', '^(?P<__prefix>(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?)User .+ not allowed because account is locked<SKIPLINES>(?P=__prefix)(?:error: )?Received disconnect from <HOST>: 11: .+ \[preauth\]$']
['set', 'sshd', 'addfailregex', '^(?P<__prefix>(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?)Disconnecting: Too many authentication failures for .+? \[preauth\]<SKIPLINES>(?P=__prefix)(?:error: )?Connection closed by <HOST> \[preauth\]$']
['set', 'sshd', 'addfailregex', '^(?P<__prefix>(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?)Connection from <HOST> port \d+(?: on \S+ port \d+)?<SKIPLINES>(?P=__prefix)Disconnecting: Too many authentication failures for .+? \[preauth\]$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?(error: )?maximum authentication attempts exceeded for .* from <HOST>(?: port \d*)?(?: ssh\d*)? \[preauth\]$']
['set', 'sshd', 'addfailregex', '^(?:\[\])?\s*(?:<[^.]+\.[^.]+>\s+)?(?:\S+\s+)?(?:kernel: \[ *\d+\.\d+\]\s+)?(?:@vserver_\S+\s+)?(?:(?:(?:\[\d+\])?:\s+[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?|[\[\(]?sshd(?:\(\S+\))?[\]\)]?:?(?:\[\d+\])?:?)\s+)?(?:\[ID \d+ \S+\]\s+)?pam_unix\(sshd:auth\):\s+authentication failure;\s*logname=\S*\s*uid=\d*\s*euid=\d*\s*tty=\S*\s*ruser=\S*\s*rhost=<HOST>\s.*$']
['set', 'sshd', 'addjournalmatch', '_SYSTEMD_UNIT=sshd.service', '+', '_COMM=sshd']
['set', 'sshd', 'addaction', 'iptables-multiport']
['set', 'sshd', 'action', 'iptables-multiport', 'actionunban', '<iptables> -D f2b-<name> -s <ip> -j <blocktype>']
['set', 'sshd', 'action', 'iptables-multiport', 'actionstop', '<iptables> -D <chain> -p <protocol> -m multiport --dports <port> -j f2b-<name>
<iptables> -F f2b-<name>
<iptables> -X f2b-<name>']
['set', 'sshd', 'action', 'iptables-multiport', 'actionban', '<iptables> -I f2b-<name> 1 -s <ip> -j <blocktype>']
['set', 'sshd', 'action', 'iptables-multiport', 'actionstart', '<iptables> -N f2b-<name>
<iptables> -A f2b-<name> -j <returntype>
<iptables> -I <chain> -p <protocol> -m multiport --dports <port> -j f2b-<name>']
['set', 'sshd', 'action', 'iptables-multiport', 'actioncheck', "<iptables> -n -L <chain> | grep -q 'f2b-<name>[ \t]'"]
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/protocol', 'tcp']
['set', 'sshd', 'action', 'iptables-multiport', 'known/chain', 'INPUT']
['set', 'sshd', 'action', 'iptables-multiport', 'known/returntype', 'RETURN']
['set', 'sshd', 'action', 'iptables-multiport', 'known/lockingopt', '-w']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/lockingopt', '-w']
['set', 'sshd', 'action', 'iptables-multiport', 'known/name', 'default']
['set', 'sshd', 'action', 'iptables-multiport', 'iptables', 'iptables <lockingopt>']
['set', 'sshd', 'action', 'iptables-multiport', 'lockingopt', '-w']
['set', 'sshd', 'action', 'iptables-multiport', 'known/blocktype', 'REJECT --reject-with icmp-port-unreachable']
['set', 'sshd', 'action', 'iptables-multiport', 'port', 'ssh']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/returntype', 'RETURN']
['set', 'sshd', 'action', 'iptables-multiport', 'returntype', 'RETURN']
['set', 'sshd', 'action', 'iptables-multiport', 'name', 'sshd']
['set', 'sshd', 'action', 'iptables-multiport', 'known/protocol', 'tcp']
['set', 'sshd', 'action', 'iptables-multiport', 'chain', 'INPUT']
['set', 'sshd', 'action', 'iptables-multiport', 'bantime', '600']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/blocktype', 'REJECT --reject-with icmp-port-unreachable']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/chain', 'INPUT']
['set', 'sshd', 'action', 'iptables-multiport', 'known/port', 'ssh']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/iptables', 'iptables <lockingopt>']
['set', 'sshd', 'action', 'iptables-multiport', 'protocol', 'tcp']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/name', 'default']
['set', 'sshd', 'action', 'iptables-multiport', 'known/iptables', 'iptables <lockingopt>']
['set', 'sshd', 'action', 'iptables-multiport', 'blocktype', 'REJECT --reject-with icmp-port-unreachable']
['set', 'sshd', 'action', 'iptables-multiport', 'known/known/port', 'ssh']
['start', 'sshd']
3）fail.conf配置项说明
dbfile = /var/lib/fail2ban/fail2ban.sqlite3
# 设置守护进程持久化数据（配置指令）所使用的设置，可以是：
# None - 不缓存重要数据（配置指令）。
# memory - 将数据（配置指令）放到内存中，服务停止则数据丢失。
# FILE - 将数据（配置指令）保存到本地文件中，服务启动时会自动读取加载，服务停止数据不会丢失
在debian中sshd默认是启用的，在/etc/fail2ban/jail.d/default*.local(具体文件不记得的)启用了sshd
jail.conf配置文件内容如下：
[INCLUDES]
before = paths-debian.conf
[DEFAULT]
ignoreip = 127.0.0.1/8
ignorecommand =
bantime = 3600
findtime = 600
maxretry = 5
backend = auto
usedns = warn
logencoding = auto
enabled = false
filter = %(__name__)s
destemail = root@localhost
sender = root@localhost
mta = sendmail
protocol = tcp
chain = INPUT
port = 0:65535
fail2ban_agent = Fail2Ban/%(fail2ban_version)s
banaction = iptables-multiport
banaction_allports = iptables-allports
action_ = %(banaction)s[name=%(__name__)s, bantime="%(bantime)s", port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
action_mw = %(banaction)s[name=%(__name__)s, bantime="%(bantime)s", port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
%(mta)s-whois[name=%(__name__)s, sender="%(sender)s", dest="%(destemail)s", protocol="%(protocol)s", chain="%(chain)s"]
action_mwl = %(banaction)s[name=%(__name__)s, bantime="%(bantime)s", port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
%(mta)s-whois-lines[name=%(__name__)s, sender="%(sender)s", dest="%(destemail)s", logpath=%(logpath)s, chain="%(chain)s"]
**解释下：%(mta)s-whois-lines等同于sendmail-whois-lines，该action存在于action.d/文件夹中**
action_xarf = %(banaction)s[name=%(__name__)s, bantime="%(bantime)s", port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
xarf-login-attack[service=%(__name__)s, sender="%(sender)s", logpath=%(logpath)s, port="%(port)s"]
action_cf_mwl = cloudflare[cfuser="%(cfemail)s", cftoken="%(cfapikey)s"]
%(mta)s-whois-lines[name=%(__name__)s, sender="%(sender)s", dest="%(destemail)s", logpath=%(logpath)s, chain="%(chain)s"]
action_blocklist_de = blocklist_de[email="%(sender)s", service=%(filter)s, apikey="%(blocklist_de_apikey)s", agent="%(fail2ban_agent)s"]
action_badips = badips.py[category="%(__name__)s", banaction="%(banaction)s", agent="%(fail2ban_agent)s"]
action_badips_report = badips[category="%(__name__)s", agent="%(fail2ban_agent)s"]
action = %(action_)s
[sshd]
port = 40022
logpath = %(sshd_log)s
backend = %(sshd_backend)s
[sshd-ddos]
port = ssh
logpath = %(sshd_log)s
backend = %(sshd_backend)s
首先看jail.conf配置文件，在该文件中的include配置节存在（before=paths-debian.conf内容如下）：
# Debian
[INCLUDES]
before = paths-common.conf
after = paths-overrides.local
[DEFAULT]
syslog_mail = /var/log/mail.log
syslog_mail_warn = /var/log/mail.warn
syslog_authpriv = /var/log/auth.log
# syslog_auth = /var/log/auth.log
#
syslog_user = /var/log/user.log
syslog_ftp = /var/log/syslog
syslog_daemon = /var/log/daemon.log
syslog_local0 = /var/log/messages
apache_error_log = /var/log/apache2/*error.log
apache_access_log = /var/log/apache2/*access.log
exim_main_log = /var/log/exim4/mainlog
# was in debian squeezy but not in wheezy
# /etc/proftpd/proftpd.conf (SystemLog)
proftpd_log = /var/log/proftpd/proftpd.log
在以上paths-debian.conf中可以看到before=paths-common.conf内容如下：
# Common
#
[INCLUDES]
after = paths-overrides.local
[DEFAULT]
default_backend = auto
sshd_log = %(syslog_authpriv)s
sshd_backend = %(default_backend)s
dropbear_log = %(syslog_authpriv)s
dropbear_backend = %(default_backend)s
# There is no sensible generic defaults for syslog log targets, thus
# leaving them empty here so that no errors while parsing/interpolating configs
syslog_daemon =
syslog_ftp =
syslog_local0 =
syslog_mail_warn =
syslog_user =
# Set the default syslog backend target to default_backend
syslog_backend = %(default_backend)s
# from /etc/audit/auditd.conf
auditd_log = /var/log/audit/audit.log
exim_main_log = /var/log/exim/mainlog
nginx_error_log = /var/log/nginx/*error.log
nginx_access_log = /var/log/nginx/*access.log
lighttpd_error_log = /var/log/lighttpd/error.log
# http://www.hardened-php.net/suhosin/configuration.html#suhosin.log.syslog.facility
# syslog_user is the default. Lighttpd also hooks errors into its log.
suhosin_log = %(syslog_user)s
%(lighttpd_error_log)s
# defaults to ftp or local2 if ftp doesn't exist
proftpd_log = %(syslog_ftp)s
proftpd_backend = %(default_backend)s
# http://svnweb.freebsd.org/ports/head/ftp/proftpd/files/patch-src_proftpd.8.in?view=markup
# defaults to ftp but can be overwritten.
pureftpd_log = %(syslog_ftp)s
pureftpd_backend = %(default_backend)s
# ftp, daemon and then local7 are tried at configure time however it is overwriteable at configure time
#
wuftpd_log = %(syslog_ftp)s
wuftpd_backend = %(default_backend)s
# syslog_enable defaults to no. so it defaults to vsftpd_log_file setting of /var/log/vsftpd.log
# No distro seems to set it to syslog by default
# If syslog set it defaults to ftp facility if exists at compile time otherwise falls back to daemonlog.
vsftpd_log = /var/log/vsftpd.log
# Technically syslog_facility in main.cf can overwrite but no-one sane does this.
postfix_log = %(syslog_mail_warn)s
postfix_backend = %(default_backend)s
dovecot_log = %(syslog_mail_warn)s
dovecot_backend = %(default_backend)s
# Seems to be set at compile time only to LOG_LOCAL0 (src/const.h) at Notice level
solidpop3d_log = %(syslog_local0)s
mysql_log = %(syslog_daemon)s
mysql_backend = %(default_backend)s
roundcube_errors_log = /var/log/roundcube/errors
# Directory with ignorecommand scripts
ignorecommands_dir = /etc/fail2ban/filter.d/ignorecommands
4）待理解
fail2ban-regex 日志文件 ‘正则表达式’ 如何使用？？
Python "string interpolation"机制？？
Using Python "string interpolation" mechanisms, other definitions are allowed and can
later be used within other definitions as %(name)s. Additionally fail2ban has an
extended interpolation feature named %(known/parameter)s (means last known option with
name parameter). This interpolation makes possible to extend a stock filter or jail reg‐
exp in .local file (opposite to simply set failregex/ignoreregex that overwrites it),
e.g.
baduseragents = IE|wget
failregex = %(known/failregex)s
useragent=%(baduseragents)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:
[Init]
test.method = GET
baduseragents = IE|wget
[Definition]
failregex = ^%(__prefix_line)s+"<test.method>"s+tests+regexps+-s+useragent=(?:<baduseragents>)
# jail.local:
[test]
# use filter "test", overwrite method to "POST" and extend known bad agents with "badagent":
filter = test[test.method=POST, baduseragents="badagent|<known/baduseragents>"]
5）参考
https://www.cnblogs.com/network-ren/p/13853770.html fail2ban系列文章
https://www.cnblogs.com/network-ren/p/13853755.html
简单配置 在vps上简单使用进行配置 https://help.skysilk.com/support/solutions/articles/9000149908--basic-how-to-install-and-configure-fail2ban-for-linux-vps
https://linux.cn/article-9299-1.html 可以参考
https://dev-notes.eu/2016/12/overriding-fail2ban-settings/ jail.conf文件的内容
https://isister.cc/posts/Fail2ban-Basic/