Iptables

Berikut contoh script install iptables dan konfigurasinya :

# !/bin/sh
# apt-get update
# apt-get install iptables
# apt-get install iptables-persistent
iptables -V
iptables -I INPUT -p tcp -s 192.168.10.202 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 1912 -j ACCEPT
iptables -A INPUT -p tcp --dport 3306 -j ACCEPT
iptables -A INPUT -p tcp --dport 5432 -j ACCEPT
iptables -A INPUT -p tcp -s 192.168.10.0/24 -j DROP
iptables -L
# iptables-save > /etc/iptables/rules.v4
# systemctl enable iptables-persistent
# service iptables-persistent start 

DDOS

iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP)
iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP)
iptables -I INPUT -p tcp --dport 80 -m state --state NEW -m recent --set)
iptables -I INPUT -p tcp --dport 80 -m state --state NEW -m recent --update --seconds 20 --hitcount 10 -j DROP)

Kalau ini manual :

# blok port 22 dari ip 192.168.10.0/24
echo "sshd: 192.168.10.0/255.255.255.0" >> /etc/hosts.deny
# open port 22 dari ip 192.168.10.202
echo "sshd: 192.168.10.202" >> /etc/hosts.allow
# open port 22 dari ip 192.168.10.36
echo "sshd: 192.168.10.36" >> /etc/hosts.allow
# open port 22 dari ip 192.168.10.29
echo "sshd: 192.168.10.29" >> /etc/hosts.allow
echo "sshd: 192.168.10.19" >> /etc/hosts.allow

Ini agar ketika di restart rule iptables tidak hilang

apt install iptables-persistent