Further reading

• 25 iptables netfilter firewall examples: https://www.cyberciti.biz/tips/linux-iptables-examples.html
• Linux IPv6 how-to: http://tldp.org/HOWTO/html_single/Linux+IPv6-HOWTO/
• Recommendations for Filtering ICMPv6 Messages in Firewalls: https://www.ietf.org/rfc/rfc4890.txt
• Rate-limiting with ufw: https://45squared.com/rate-limiting-with-ufw/
• UFW Community Help Wiki: https://help.ubuntu.com/community/UFW
• How to set up a Linux firewall with UFW on Ubuntu 18.04: https://linuxize.com/post/how-to-setup-a-firewall-with-ufw-on-ubuntu-18-04/