ufw (uncomplicated firewall) makes it easy to allow or deny specific ports or services.
install ufw if it is not already installed.
sudo apt-get -y install ufw
enable ufw to run at boot time. since no rules are added, this will not affect your current ssh session.
sudo ufw enable
allow traffic for http, https and ssh. you can specify service names, but for this example, we specify port numbers.
sudo ufw allow 22 sudo ufw allow 80 sudo ufw allow 443
restart ufw to apply the changes immediately.
sudo service ufw restart
verify that the rules were properly applied:
sudo ufw status verbose
the projected output should look like the following:
Status: active Logging: on (low) Default: deny (incoming), allow (outgoing) New profiles: skip To Action From -- ------ ---- 22 ALLOW IN Anywhere 80 ALLOW IN Anywhere 443 ALLOW IN Anywhere 22 ALLOW IN Anywhere (v6) 80 ALLOW IN Anywhere (v6) 443 ALLOW IN Anywhere (v6)
done. firewall installed and enabled at boot time, filtering all traffic except http, https and ssh. please note that this does not filter outbound traffic in any way, it merely firewalls off all ports except those specified above.
giraffeheads 