What type of access control can block traffic based on the source address?

The choice of a standard ACL as the correct answer is based on its design to filter traffic primarily based on the source IP address. Standard access control lists (ACLs) are typically used to permit or deny traffic originating from specific source addresses, thus providing a straightforward means of controlling access on a network.

Standard ACLs work at Layer 3 of the OSI model, where they examine the IP header of packets to determine their source address. This allows network administrators to create rules that block or allow data packets based on where they come from. For example, if a standard ACL is configured to deny all traffic coming from a specific IP address, any packets from that address will be blocked from entering the network or reaching certain devices.

In contrast, other types of access controls mentioned in the options have different functionalities. Extended ACLs can filter traffic based on both source and destination IP addresses as well as protocol types and port numbers, making them more versatile but not solely focused on the source address. Restrictive access control is a broader term and does not specifically refer to any standard mechanism in the context of network access control. A transparent firewall operates at a different level, focusing on traffic monitoring and filtering without modifying the IP address, which does not directly relate to controlling