Access Control Lists (ACLs) in networking are categorized into two main types: standard ACLs and extended ACLs.
Standard ACLs: Standard ACLs filter traffic based solely on the source IP address of packets. They are simpler in operation compared to extended ACLs but provide less granularity in controlling network traffic. Standard ACLs are typically applied closest to the destination network in order to filter traffic based on its source IP address.
Extended ACLs: Extended ACLs provide more advanced filtering capabilities compared to standard ACLs. They can filter traffic based on multiple criteria, including source and destination IP addresses, protocols, port numbers, and other Layer 3 and Layer 4 information. Extended ACLs offer greater flexibility in defining access control policies and are applied closer to the source network to control outbound traffic more effectively.
In Cisco networking, the different types of access lists include:
- Standard Access Lists (1-99 and 1300-1999): These ACLs filter traffic based on source IP addresses only.
- Extended Access Lists (100-199 and 2000-2699): These ACLs offer more detailed filtering capabilities, including source and destination IP addresses, protocols, port numbers, and other criteria.
- Named Access Lists: Named ACLs are user-defined ACLs that provide similar functionality to numbered ACLs but use alphanumeric names instead of numeric identifiers for easier management and identification.
Each type of ACL serves specific purposes in controlling network traffic based on the level of detail required for access control policies within Cisco networking environments.