Which of the following would restrict traffic from a specific host to a network?

MIBs (Management Information Bases) are used in SNMP for organizing and identifying managed objects in a network, not for restricting traffic.

NAS (Network-Attached Storage) is a file-level data storage server connected to a computer network, and does not restrict general network traffic.

An Access Control List (ACL) is a set of rules applied to a network interface or firewall that explicitly permits or denies network traffic based on criteria such as source and destination IP addresses, protocols, and port numbers. By configuring an ACL with a deny rule for a specific host's IP address, traffic originating from or destined for that host can be effectively restricted from accessing a network.

SMTP (Simple Mail Transfer Protocol) is an application-layer protocol for sending email, and does not restrict general network traffic.