ASL STEM

Definition

Like standard ACLs, extended ACLs check the source packet addresses, destination address, protocols and port numbers. Extended Access Control Lists (ACLs) provide a greater range of control and, therefore, an addition to your security solution. Extended ACLs provides for more precise traffic-filtering control, you can use extended ACLs numbered 100 to 199 and 2000 to 2699 providing a total of 800 possible extended ACLs. Extended ACLs can also be named.

Source: http://www.orbit-computer-solutions.com/Extended-ACLs.php