What is a key reason that default-allow firewall rules can be risky?

Default-allow firewall rules can lead to unintended network connections because they permit all types of traffic by default, unless explicitly denied. This means that any device or application that tries to connect to the network may be allowed access, regardless of whether it’s legitimate or secure. As a result, malicious traffic, unauthorized devices, or malware can exploit these open pathways, posing significant risks to the security of the network. By not restricting traffic, default-allow rules can create vulnerabilities that may go unnoticed until an incident occurs, fundamentally undermining the effectiveness of network security measures.

In contrast, approaches that employ default-deny rules—where all traffic is blocked unless it is specifically permitted—are generally considered more secure because they require explicit permission for any connection to be established, reducing the risk of unauthorized access.