What is the command to enter extended named ACL config mode?

The command to enter extended named ACL configuration mode is "ip access-list extended {name | number}". This command is specifically designed for defining extended access control lists, which allow for more granular control over traffic by enabling a combination of both source and destination IP addresses and protocols.

When using this command, the "ip" prefix indicates that it is related to Internet Protocol (IP), and "access-list" specifies that this is indeed an access list configuration. The term "extended" distinguishes this ACL from standard ones, signifying that it can filter traffic based on a variety of criteria beyond just source IP addresses, such as the destination IP address, protocol type, and port numbers.

Using the correct format ensures that users can effectively configure ACLs that meet their network security requirements, allowing for decisions to be made based on detailed protocol and address information rather than the simpler criteria of standard ACLs.