cat /etc/fail2ban/action.d/hostsdeny.conf
# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 660 $
#
[Definition]
# Option: actionstart
# Notes.: command executed once at the start of Fail2Ban.
# Values: CMD
#
actionstart =
# Option: actionstop
# Notes.: command executed once at the end of Fail2Ban
# Values: CMD
#
actionstop =
# Option: actioncheck
# Notes.: command executed once before each actionban command
# Values: CMD
#
actioncheck =
# Option: actionban
# Notes.: command executed when banning an IP. Take care that the
# command is executed with Fail2Ban user rights.
# Tags: <ip> IP address
# <failures> number of failures
# <time> unix timestamp of the ban time
# Values: CMD
#
actionban = IP=<ip> &&
printf %%b "ALL: $IP\n" >> <file>
# Option: actionunban
# Notes.: command executed when unbanning an IP. Take care that the
# command is executed with Fail2Ban user rights.
# Tags: <ip> IP address
# <failures> number of failures
# <time> unix timestamp of the ban time
# Values: CMD
#
actionunban = IP=<ip> && sed -i.old /ALL:\ $IP/d <file>
[Init]
# Option: file
# Notes.: hosts.deny file path.
# Values: STR Default: /etc/hosts.deny
#
file = /etc/hosts.deny