Setup Firewall with UFW on Debian/Ubuntu

gistfile1.txt

#See https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-with-ufw-on-ubuntu-16-04 for more details on UFW commands

#change to root
sudo -i

#install ufw
apt install ufw

#enable writing logs to separate file https://askubuntu.com/a/728657
sed -i '/^#& ~/s/^#//' /etc/rsyslog.d/20-ufw.conf
/etc/init.d/rsyslog restart

#(optional) if you become stuck, start at this point and run down again.
ufw reset

#add rules
ufw allow from 192.168.8.0/22
#ufw allow from 192.168.8.0/22 to any port 22
#ufw allow from 192.168.8.0/22 to any port 443

#block all incoming and allow all outgoing
ufw default deny incoming
ufw default allow outgoing

#review rules
less /lib/ufw/user.rules

#enable firewall (be careful you haven't locked yourself out! If you are over terminal, ensure 22 for your IP address is available)
ufw enable
ufw status verbose

#try out the rules
watch -d --interval 0 'iptables -nvL | grep -v "0 0"'


#clean up any old rules if you don't need them.
rm /lib/ufw/user{,6}.rules.*
rm /etc/ufw/before{,6}.rules.*
rm /etc/ufw/after{,6}.rules.*