Which type of access control is used on a router or firewall to limit network activity?

Mandatory access control (MAC) uses sensitivity labels and security clearances assigned to subjects and objects - not applicable to packet-level network filtering.

Discretionary access control (DAC) lets resource owners set permissions on their own resources, which does not map to how routers or firewalls filter traffic.

Rule-based access control (RuBAC) grants or denies access based on a set of predefined rules configured by an administrator, which is exactly how router ACLs and firewall policies function. Each packet is evaluated against an ordered rule set and permitted or denied based on criteria like source IP, destination IP, port, and protocol. This model is distinct from role-based control because access is tied to traffic attributes, not user identities.

Role-based access control (RBAC) grants access based on a user's assigned role within an organization, not on network traffic rules.