Configure Extended IPv4 ACLs:
Extended ACLs are used more often than standard ACLs because they provide a greater degree of control. They can filter on source address, destination address, protocol (i.e., IP, TCP, UDP, ICMP), and port number. This provides a greater range of criteria on which to base the ACL. For example, one extended ACL can allow email traffic from a network to a specific destination while denying file transfers and web browsing.
Like standard ACLs, extended ACLs can be created as:
Numbered Extended ACL - Created using the access-list access-list-number global configuration command.
Named Extended ACL - Created using the ip access-list extended access-list-name.
