CCNA: Access-Lists (Standard and Extended)

 In Cisco networking, an access list (or ACL) is a set of rules that defines what traffic is allowed or denied to pass through a network device, such as a router or switch. Access lists are used to filter and control network traffic based on criteria such as source and destination IP addresses, protocols, and ports. Access lists can be applied to inbound or outbound traffic on an interface, and they can be used to permit or deny traffic.

Access lists are identified by a number, which can range from 1 to 199 for standard IPv4 access lists, 100 to 199 for extended IPv4 access lists, 2000 to 2699 for standard IPv6 access lists, and 2700 to 2799 for extended IPv6 access lists.

There are two types of access lists in Cisco networking:

Standard access lists: These access lists match traffic based on the source IP address only. They are identified by a number from 1 to 99 (IPv4) or 1300 to 1999 (IPv6).

Extended access lists: These access lists match traffic based on multiple criteria, such as source and destination IP addresses, protocols, and ports. They are identified by a number from 100 to 199 (IPv4) or 2000 to 2699 (IPv6).

Check this video on Access-Lists (Standard and Extended): CCNA Training