iptables -A INPUT -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT
# Allow the local loopback interface (i.e., access to the machine running native)
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
# Allow established or even relevant passage
iptables -A OUTPUT -j ACCEPT
Allows access to all local # outwardly
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
# Allow access to port 22
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
# Allow access to port 80
iptables -A INPUT -p tcp --dport 21 -j ACCEPT
# 21 port allows ftp services
iptables -A INPUT -p tcp --dport 20 -j ACCEPT
# FTP services allow port 20
iptables -A INPUT -j reject
# Prohibit other rules are not allowed access
iptables -A FORWARD -j REJECT
# Prohibit other rules are not allowed access