What distinguishes standard ACLs from extended ACLs in networking?

Standard Access Control Lists (ACLs) primarily focus on filtering traffic based on the source IP address. This means that when a standard ACL is applied to a network interface, it can only permit or deny traffic originating from specific IP addresses without taking into account additional parameters like the destination IP address, protocols, or port numbers.

This simplicity is both a strength and a limitation. By only evaluating the source IP address, standard ACLs are straightforward to configure and often used for basic filtering needs. However, they do not provide the granularity that extended ACLs offer, which can filter traffic based on both source and destination IP addresses, as well as on protocols (like TCP or UDP) and port numbers.

In contrast, extended ACLs have the capability to filter based on multiple criteria – source and destination IP addresses, protocols, and specific port numbers – allowing for more refined control over network traffic.

So, the role of a standard ACL, which restricts its evaluation to just the source IP, clearly sets it apart from extended ACLs that provide a broader range of filtering capabilities.