Fail2ban startup fail on Debian

Error message

The key message: Failed during configuration: Have not found any log file for sshd jail

➜ ~ /usr/bin/fail2ban-server -xf start
2024-11-11 02:12:02,637 fail2ban.configreader   [1255228]: WARNING 'allowipv6' not defined in 'Definition'. Using default one: 'auto'
2024-11-11 02:12:02,647 fail2ban                [1255228]: ERROR   Failed during configuration: Have not found any log file for sshd jail
2024-11-11 02:12:02,651 fail2ban                [1255228]: ERROR   Async configuration of server failed

Solution

Edit /etc/fail2ban/jail.local

On [Default] add backend=systemd will fix the issue.

nano /etc/fail2ban/jail.local

[DEFAULT]
backend=systemd
ignoreip = 127.0.0.1
bantime = 86400
maxretry = 5
findtime = 1800

[ssh-iptables]
enabled = true
filter = sshd
action = iptables[name=SSH, port=ssh, protocol=tcp]
logpath = /var/log/auth.log
maxretry = 5
findtime = 3600
bantime = 31536000

Reference

1. https://github.com/fail2ban/fail2ban/issues/3292#issuecomment-1142579029

Photo by Brusk Dede on Unsplash

Script to install fail2ban

#!/bin/bash

CHECK_OS(){
	if [[ -f /etc/redhat-release ]]; then
		release="centos"
	elif grep -q -E -i "debian" /etc/issue; then
		release="debian"
	elif grep -q -E -i "ubuntu" /etc/issue; then
		release="ubuntu"
	elif grep -q -E -i "centos|red hat|redhat" /etc/issue; then
		release="centos"
	elif grep -q -E -i "debian" /proc/version; then
		release="debian"
	elif grep -q -E -i "ubuntu" /proc/version; then
		release="ubuntu"
	elif grep -q -E -i "centos|red hat|redhat" /proc/version; then
		release="centos"
	fi
}

GET_SETTING_FAIL2BAN_INFO(){
	read -p "允许SSH登陆失败次数,默认10: " BLOCKING_THRESHOLD
	[[ -z "${BLOCKING_THRESHOLD}" ]] && BLOCKING_THRESHOLD=10

	read -p "SSH登陆失败次数超过${BLOCKING_THRESHOLD}次时,封禁时长(h),默认8760: " BLOCKING_TIME_H
	[[ -z "${BLOCKING_TIME_H}" ]] && BLOCKING_TIME_H=8760

	BLOCKING_TIME_S=$((BLOCKING_TIME_H * 3600))
}

INSTALL_FAIL2BAN(){
	if [ ! -e /etc/fail2ban/jail.local ]; then
		CHECK_OS
		case "${release}" in
			centos)
				GET_SETTING_FAIL2BAN_INFO
				yum -y install epel-release
				yum -y install fail2ban
				;;
			debian|ubuntu)
				GET_SETTING_FAIL2BAN_INFO
				apt-get -y install fail2ban
				;;
			*)
				echo "请使用CentOS,Debian,Ubuntu系统."
				exit 1
				;;
		esac
	else
		echo "fail2ban已经安装了."
		exit 0
	fi
}

REMOVE_FAIL2BAN(){
	if [ -e /etc/fail2ban/jail.local ]; then
		CHECK_OS
		case "${release}" in
			centos)
				systemctl stop fail2ban
				yum -y remove fail2ban
				rm -rf /etc/fail2ban/jail.local
				;;
			debian|ubuntu)
				systemctl stop fail2ban
				apt-get -y remove fail2ban
				rm -rf /etc/fail2ban/jail.local
				;;
		esac
	else
		echo "fail2ban尚未安装."
		exit 0
	fi
}

SETTING_FAIL2BAN(){
	CHECK_OS
	case "${release}" in
		centos|debian|ubuntu)
			cat > /etc/fail2ban/jail.local <<EOF
[DEFAULT]
backend = systemd
ignoreip = 127.0.0.1
bantime = 86400
maxretry = ${BLOCKING_THRESHOLD}
findtime = 1800

[ssh-iptables]
enabled = true
filter = sshd
action = iptables[name=SSH, port=ssh, protocol=tcp]
logpath = $( [[ "$release" == "centos" ]] && echo "/var/log/secure" || echo "/var/log/auth.log" )
maxretry = ${BLOCKING_THRESHOLD}
findtime = 3600
bantime = ${BLOCKING_TIME_S}
EOF
			systemctl restart fail2ban
			systemctl enable fail2ban
			systemctl restart sshd
			;;
	esac
}

VIEW_RUN_LOG(){
	CHECK_OS
	case "${release}" in
		centos)
			tail -f /var/log/secure
			;;
		debian|ubuntu)
			tail -f /var/log/auth.log
			;;
	esac
}

case "${1}" in
	install)
		INSTALL_FAIL2BAN
		SETTING_FAIL2BAN
		;;
	uninstall)
		REMOVE_FAIL2BAN
		;;
	status)
		echo -e "\033[41;37m【进程】\033[0m"
		ps aux | grep fail2ban
		echo
		echo -e "\033[41;37m【状态】\033[0m"
		fail2ban-client ping
		echo
		echo -e "\033[41;37m【Service】\033[0m"
		service fail2ban status
		;;
	blocklist|bl)
		[ -e /etc/fail2ban/jail.local ] && fail2ban-client status ssh-iptables || echo "fail2ban尚未安装."
		;;
	unlock|ul)
		[ -e /etc/fail2ban/jail.local ] || { echo "fail2ban尚未安装."; exit 0; }
		if [[ -z "${2}" ]]; then
			read -p "请输入需要解封的IP: " UNLOCK_IP
			[[ -z "${UNLOCK_IP}" ]] && { echo "不允许空值,请重试."; exit 1; }
			fail2ban-client set ssh-iptables unbanip "${UNLOCK_IP}"
		else
			fail2ban-client set ssh-iptables unbanip "${2}"
		fi
		;;
	more)
		echo "【参考文章】
https://www.fail2ban.org
https://linux.cn/article-5067-1.html

【更多命令】
fail2ban-client -h"
		;;
	runlog)
		VIEW_RUN_LOG
		;;
	start)
		systemctl start fail2ban
		;;
	stop)
		systemctl stop fail2ban
		;;
	restart)
		systemctl restart fail2ban
		;;
	*)
		echo "bash fail2ban.sh {install|uninstall|runlog|more}"
		echo "bash fail2ban.sh {start|stop|restart|status}"
		echo "bash fail2ban.sh {blocklist|unlock}"
		;;
esac

#END