si ça peut t’aider,chez moi
$ fail2ban-client -d
2024-01-24 19:10:07,338 fail2ban.configreader [10472]: WARNING 'allowipv6' not defined in 'Definition'. Using default one: 'auto'
['set', 'syslogsocket', 'auto']
['set', 'loglevel', 'INFO']
['set', 'logtarget', '/var/log/fail2ban.log']
['set', 'allowipv6', 'auto']
['set', 'dbfile', '/var/lib/fail2ban/fail2ban.sqlite3']
['set', 'dbmaxmatches', 10]
['set', 'dbpurgeage', '1d']
['add', 'sshd', 'auto']
['set', 'sshd', 'usedns', 'warn']
['set', 'sshd', 'prefregex', '^<F-MLFID>(?:\\[\\])?\\s*(?:<[^.]+\\.[^.]+>\\s+)?(?:\\S+\\s+)?(?:kernel:\\s?\\[ *\\d+\\.\\d+\\]:?\\s+)?(?:@vserver_\\S+\\s+)?(?:(?:(?:\\[\\d+\\])?:\\s+[\\[\\(]?sshd(?:\\(\\S+\\))?[\\]\\)]?:?|[\\[\\(]?sshd(?:\\(\\S+\\))?[\\]\\)]?:?(?:\\[\\d+\\])?:?)\\s+)?(?:\\[ID \\d+ \\S+\\]\\s+)?</F-MLFID>(?:(?:error|fatal): (?:PAM: )?)?<F-CONTENT>.+</F-CONTENT>$']
['set', 'sshd', 'maxlines', 1]
['multi-set', 'sshd', 'addfailregex', ['^[aA]uthentication (?:failure|error|failed) for <F-USER>.*</F-USER> from <HOST>( via \\S+)?(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User not known to the underlying authentication module for <F-USER>.*</F-USER> from <HOST>(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^Failed publickey for invalid user <F-USER>(?P<cond_user>\\S+)|(?:(?! from ).)*?</F-USER> from <HOST>(?: (?:port \\d+|on \\S+)){0,2}(?: ssh\\d*)?(?(cond_user): |(?:(?:(?! from ).)*)$)', '^Failed (?:<F-NOFAIL>publickey</F-NOFAIL>|\\S+) for (?P<cond_inv>invalid user )?<F-USER>(?P<cond_user>\\S+)|(?(cond_inv)(?:(?! from ).)*?|[^:]+)</F-USER> from <HOST>(?: (?:port \\d+|on \\S+)){0,2}(?: ssh\\d*)?(?(cond_user): |(?:(?:(?! from ).)*)$)', '^<F-USER>ROOT</F-USER> LOGIN REFUSED FROM <HOST>', '^[iI](?:llegal|nvalid) user <F-USER>.*?</F-USER> from <HOST>(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User <F-USER>\\S+|.*?</F-USER> from <HOST> not allowed because not listed in AllowUsers(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User <F-USER>\\S+|.*?</F-USER> from <HOST> not allowed because listed in DenyUsers(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User <F-USER>\\S+|.*?</F-USER> from <HOST> not allowed because not in any group(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^refused connect from \\S+ \\(<HOST>\\)', '^Received <F-MLFFORGET>disconnect</F-MLFFORGET> from <HOST>(?: (?:port \\d+|on \\S+)){0,2}:\\s*3: .*: Auth fail(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User <F-USER>\\S+|.*?</F-USER> from <HOST> not allowed because a group is listed in DenyGroups(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', "^User <F-USER>\\S+|.*?</F-USER> from <HOST> not allowed because none of user's groups are listed in AllowGroups(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$", '^<F-NOFAIL>pam_[a-z]+\\(sshd:auth\\):\\s+authentication failure;</F-NOFAIL>(?:\\s+(?:(?:logname|e?uid|tty)=\\S*)){0,4}\\s+ruser=<F-ALT_USER>\\S*</F-ALT_USER>\\s+rhost=<HOST>(?:\\s+user=<F-USER>\\S*</F-USER>)?(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^maximum authentication attempts exceeded for <F-USER>.*</F-USER> from <HOST>(?: (?:port \\d+|on \\S+)){0,2}(?: ssh\\d*)?(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^User <F-USER>\\S+|.*?</F-USER> not allowed because account is locked(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*', '^<F-MLFFORGET>Disconnecting</F-MLFFORGET>(?: from)?(?: (?:invalid|authenticating)) user <F-USER>\\S+</F-USER> <HOST>(?: (?:port \\d+|on \\S+)){0,2}:\\s*Change of username or service not allowed:\\s*.*\\[preauth\\]\\s*$', '^Disconnecting: Too many authentication failures(?: for <F-USER>\\S+|.*?</F-USER>)?(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*$', '^<F-NOFAIL>Received <F-MLFFORGET>disconnect</F-MLFFORGET></F-NOFAIL> from <HOST>(?: (?:port \\d+|on \\S+)){0,2}:\\s*11:', '^<F-NOFAIL><F-MLFFORGET>(Connection (?:closed|reset)|Disconnected)</F-MLFFORGET></F-NOFAIL> (?:by|from)(?: (?:invalid|authenticating) user <F-USER>\\S+|.*?</F-USER>)? <HOST>(?:(?: (?:port \\d+|on \\S+|\\[preauth\\])){0,3}\\s*|\\s*)$', '^<F-MLFFORGET><F-MLFGAINED>Accepted \\w+</F-MLFGAINED></F-MLFFORGET> for <F-USER>\\S+</F-USER> from <HOST>(?:\\s|$)', '^<F-NOFAIL>Connection from</F-NOFAIL> <HOST>']]
['set', 'sshd', 'datepattern', '{^LN-BEG}']
['set', 'sshd', 'addjournalmatch', '_SYSTEMD_UNIT=sshd.service', '+', '_COMM=sshd']
['set', 'sshd', 'maxretry', 5]
['set', 'sshd', 'maxmatches', 5]
['set', 'sshd', 'findtime', '10m']
['set', 'sshd', 'bantime', '10m']
['set', 'sshd', 'ignorecommand', '']
['set', 'sshd', 'logencoding', 'auto']
['set', 'sshd', 'addlogpath', '/var/log/auth.log', 'head']
['set', 'sshd', 'addaction', 'iptables-multiport']
['multi-set', 'sshd', 'action', 'iptables-multiport', [['actionstart', "{ <iptables> -C f2b-sshd -j RETURN >/dev/null 2>&1; } || { <iptables> -N f2b-sshd || true; <iptables> -A f2b-sshd -j RETURN; }\nfor proto in $(echo 'tcp' | sed 's/,/ /g'); do\n{ <iptables> -C INPUT -p $proto -m multiport --dports ssh -j f2b-sshd >/dev/null 2>&1; } || { <iptables> -I INPUT -p $proto -m multiport --dports ssh -j f2b-sshd; }\ndone"], ['actionstop', "for proto in $(echo 'tcp' | sed 's/,/ /g'); do\n<iptables> -D INPUT -p $proto -m multiport --dports ssh -j f2b-sshd\ndone\n<iptables> -F f2b-sshd\n<iptables> -X f2b-sshd"], ['actionflush', '<iptables> -F f2b-sshd'], ['actioncheck', "for proto in $(echo 'tcp' | sed 's/,/ /g'); do\n<iptables> -C INPUT -p $proto -m multiport --dports ssh -j f2b-sshd\ndone"], ['actionban', '<iptables> -I f2b-sshd 1 -s <ip> -j <blocktype>'], ['actionunban', '<iptables> -D f2b-sshd -s <ip> -j <blocktype>'], ['port', 'ssh'], ['protocol', 'tcp'], ['chain', '<known/chain>'], ['name', 'sshd'], ['actname', 'iptables-multiport'], ['blocktype', 'REJECT --reject-with icmp-port-unreachable'], ['returntype', 'RETURN'], ['lockingopt', '-w'], ['iptables', 'iptables <lockingopt>'], ['blocktype?family=inet6', 'REJECT --reject-with icmp6-port-unreachable'], ['iptables?family=inet6', 'ip6tables <lockingopt>']]]
['start', 'sshd']
et mon /var/log/fail2ban.log
2024-01-24 17:50:54,915 fail2ban.server [1352]: INFO Starting Fail2ban v1.0.2
2024-01-24 17:50:54,916 fail2ban.observer [1352]: INFO Observer start...
2024-01-24 17:50:55,616 fail2ban.database [1352]: INFO Connected to fail2ban persistent database '/var/lib/fail2ban/fail2ban.sqlite3'
2024-01-24 17:50:55,740 fail2ban.jail [1352]: INFO Creating new jail 'sshd'
2024-01-24 17:51:31,474 fail2ban.jail [1352]: INFO Jail 'sshd' uses pyinotify {}
2024-01-24 17:51:31,489 fail2ban.jail [1352]: INFO Initiated 'pyinotify' backend
2024-01-24 17:51:31,492 fail2ban.filter [1352]: INFO maxLines: 1
2024-01-24 17:51:31,508 fail2ban.filter [1352]: INFO maxRetry: 5
2024-01-24 17:51:31,509 fail2ban.filter [1352]: INFO findtime: 600
2024-01-24 17:51:31,509 fail2ban.actions [1352]: INFO banTime: 600
2024-01-24 17:51:31,509 fail2ban.filter [1352]: INFO encoding: UTF-8
2024-01-24 17:51:31,555 fail2ban.filter [1352]: INFO Added logfile: '/var/log/auth.log' (pos = 3120789, hash = d72d366c2f8210daa2eec22aca47174c6eefc69f)
2024-01-24 17:51:31,654 fail2ban.jail [1352]: INFO Jail 'sshd' started
où on voit que j’utilise pyinotify pas systemd, mais sans volonté particulière ( je fais des upgrades des debian depuis deb9 ou deb10
mais je ne sais pas si ça bloque les attaques ( je n’ai pas de ssh autorisé , donc pas d’attaques )
