Firewalls are important at promoting protection for your home or business. As the first line of defense it is important to have a good a properly configured firewall.
I'm a huge fan of pfSense firewall/router/VPN/DHCP server/Data Snooping wonder, which is free and based on the more secure FreeBSD operating system.
Found this Barebones Firewall and installed pfSense on it and after configuring it, I finally feel safe at home.
The best way to describe it is a common router on strodes. Easy to use but will take time to configure.
https://www.linuxincluded.com/block-ads-malvertising-on-pfsense-using-pfblockerng-dnsbl-old/ - PFBlocker
https://www.cyberciti.biz/faq/how-to-pfsense-configure-network-interface-as-a-bridge-network-switch/
https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers - Useful to know Ports and what they normally do