Firewall of kali

   Kali操作系统安装时默认已经安装了"iptables"防火墙，配置前先检查是否安装，执行：iptables -L

root@kali:~# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
root@kali:~# 

Iptables described above has been installed, if not installed, execute: apt-get install iptables installed with " " means to "iptables" all relevant packages are installed, to prevent the installation of dependencies not lead to "iptables" installation failed.