Se eu não estiver errado, você não instalou nenhum MTA (sendmail / postfix) no servidor. Tente reiniciar o fail2ban depois de instalar o sendmail / postfix.
Eu corrigi o problema depois de instalar o MTA.
Instalei o fail2ban no meu servidor (SO: Ubuntu 16.0.4 LTS). Quando tento iniciá-lo, recebo a seguinte mensagem de erro:
Job for fail2ban.service failed because the control process exited with error code.
Aqui estão as saídas para vários comandos de diagnóstico:
morpheous@ZEUS:~$ sudo systemctl status fail2ban.service
● fail2ban.service - Fail2Ban Service
Loaded: loaded (/lib/systemd/system/fail2ban.service; enabled; vendor preset: enabled)
Active: inactive (dead) (Result: exit-code) since Sat 2016-10-29 11:46:36 UTC; 18s ago
Docs: man:fail2ban(1)
Process: 23122 ExecStart=/usr/bin/fail2ban-client -x start (code=exited, status=255)
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Unit entered failed state.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Failed with result 'exit-code'.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Oct 29 11:46:36 ZEUS systemd[1]: Stopped Fail2Ban Service.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Start request repeated too quickly.
Oct 29 11:46:36 ZEUS systemd[1]: Failed to start Fail2Ban Service.
morpheous@ZEUS:~$ sudo journalctl -xe
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Oct 29 11:46:36 ZEUS systemd[1]: Stopped Fail2Ban Service.
-- Subject: Unit fail2ban.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit fail2ban.service has finished shutting down.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Start request repeated too quickly.
Oct 29 11:46:36 ZEUS systemd[1]: Failed to start Fail2Ban Service.
-- Subject: Unit fail2ban.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit fail2ban.service has failed.
--
-- The result is failed.
Oct 29 11:46:55 ZEUS sudo[23124]: morpheous : TTY=pts/0 ; PWD=/home/morpheous ; USER=root ; COMMAND=/bin/systemctl status fail2ban.service
Oct 29 11:46:55 ZEUS sudo[23124]: pam_unix(sudo:session): session opened for user root by morpheous(uid=0)
Oct 29 11:46:55 ZEUS sudo[23124]: pam_unix(sudo:session): session closed for user root
Oct 29 11:47:01 ZEUS kernel: iptables_INPUT_denied: IN=eth0 OUT= MAC=[mac_address] SRC=[lan_ip_address] DST=[server_ip_address]
Oct 29 11:47:09 ZEUS sudo[23128]: morpheous : TTY=pts/0 ; PWD=/home/morpheous ; USER=root ; COMMAND=/bin/journalctl -xe
Oct 29 11:47:09 ZEUS sudo[23128]: pam_unix(sudo:session): session opened for user root by morpheous(uid=0)
lines 1353-1374/1374 (END)
Alguém sabe o que está acontecendo aqui e, mais importante, como resolver esse problema?
Se eu não estiver errado, você não instalou nenhum MTA (sendmail / postfix) no servidor. Tente reiniciar o fail2ban depois de instalar o sendmail / postfix.
Eu corrigi o problema depois de instalar o MTA.
Por Homicculus Reticulli , 29 de outubro de 2016 às 18:26 , a seguinte sugestão resolveu meu problema :
cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local