BSK Lab1 firewall.sh

gistfile1.txt

iptables -F
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP
#icmp
iptables -A OUTPUT -o eno16777728 --proto icmp -m icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -i eno16777728 --proto icmp -m icmp --icmp-type echo-reply -j ACCEPT
#dns
iptables -A OUTPUT -o eno16777728 -p udp -m udp --dport 53 -m state --state NEW -j ACCEPT
iptables -A INPUT -i eno16777728 -p udp -m udp --sport 53 -m state --state ESTABLISHED,RELATED -j ACCEPT
#ssh
iptables -A INPUT -i eno16777728 -p tcp -m tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eno16777728 -p tcp -m tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
#ssh particular host allowed
iptables -A INPUT -i eno16777728 -p tcp -m tcp --dport 22 -s 100.120.12.10 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eno16777728 -p tcp -m tcp --sport 22 -d 100.120.12.10 -m state --state ESTABLISHED -j ACCEPT