How Does Firewall Security Work?
Simple Firewalls
Firewalls are typically governed by rules, although some simpler firewalls just use network address translation (NAT) to hide the internal networks from external networks) and open ports which, whilst often sufficient for domestic use, are not always sufficient for business use, especially if the business is hosting its own IT systems that require some presentation to the internet and this is where more comprehensive rules-based firewalls are typically deployed.
Rule Based Firewalls
Rule based firewall security works across different layers of the OSI network protocol model allowing different layers to be queried and appropriate rules applied. This way a far more granular way of controlling inbound and outbound network traffic, adding better network security to your configuration.