如何在通过 SSH 会话测试远程服务器配置时自动重置 Linux 防火墙

#!/bin/bash
# reset.fw - Reset firewall
# set x to 0 - No reset
# set x to 1 - Reset firewall
# ---------------------------------------------------------------------------------------------------------------
# Added support for IPV6 Firewall
# ---------------------------------------------------------------------------------------------------------------
# Written by Vivek Gite <vivek@example.com>
# ---------------------------------------------------------------------------------------------------------------
# You can copy / paste / redistribute this script under GPL version 2.0 or above
# =============================================================
x=1
 
# set to true if it is CentOS / RHEL / Fedora box
RHEL=false
 
# set true if it is CentOS/RHEL v7.x or above
RHEL7=false
 
### no need to edit below  ###
IPT=/sbin/iptables
IPT6=/sbin/ip6tables
 
if [ "$x" == "1" ];
then
	if [ "$RHEL" == "true" ];
	then
	      # reset firewall using redhat script
               if [ "$RHEL7" == "true" ];
               then
                 systemctl stop iptables
                 systemctl stop ip6tables
               else  ## old rhel <= v6.x ##
		         /etc/init.d/iptables stop
		         /etc/init.d/ip6tables stop
               fi
	else
		# for all other Linux distro use following rules to reset firewall
		### reset ipv4 iptales ###
		$IPT -F
		$IPT -X
		$IPT -Z
		for table in $(</proc/net/ip_tables_names)
		do
			$IPT -t $table -F
			$IPT -t $table -X
			$IPT -t $table -Z
		done
		$IPT -P INPUT ACCEPT
		$IPT -P OUTPUT ACCEPT
		$IPT -P FORWARD ACCEPT
		### reset ipv6 iptales ###
		$IPT6 -F
		$IPT6 -X
		$IPT6 -Z
		for table in $(</proc/net/ip6_tables_names)
		do
			$IPT6 -t $table -F
			$IPT6 -t $table -X
			$IPT6 -t $table -Z
		done
		$IPT6 -P INPUT ACCEPT
		$IPT6 -P OUTPUT ACCEPT
		$IPT6 -P FORWARD ACCEPT
	fi
else
        :
fi

iptables -P INPUT DROP
iptables -P OUTPUT DROP
# only accept ssh port (add other as per need such as HTTP 80 or HTTPS 443)
iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
iptables -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED,RELATED -j ACCEPT

...
	else
		# for all other Linux distro use following rules to reset firewall
		### reset ipv4 iptales ###
		$IPT -F
		$IPT -X
		$IPT -Z
		for table in $(</proc/net/ip_tables_names)
		do
			$IPT -t $table -F
			$IPT -t $table -X
			$IPT -t $table -Z
		done
		$IPT -P INPUT ACCEPT
		$IPT -P OUTPUT ACCEPT
		$IPT -P FORWARD ACCEPT
		#Uncommet to drop everything but only allow ssh over ipv4 ##
		#$IPT -P INPUT DROP
		#$IPT -P OUTPUT DROP
		#$IPT -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
		#$IPT -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED,RELATED -j ACCEPT
		### reset ipv6 iptales ###
		$IPT6 -F
		$IPT6 -X
		$IPT6 -Z
		for table in $(</proc/net/ip6_tables_names)
		do
			$IPT6 -t $table -F
			$IPT6 -t $table -X
			$IPT6 -t $table -Z
		done
		$IPT6 -P INPUT ACCEPT
		$IPT6 -P OUTPUT ACCEPT
		$IPT6 -P FORWARD ACCEPT
	fi
...