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Module 4: ACL Concepts - Coggle Diagram

- - - - Limit network traffic to increase
        network performance
      - Provide traffic flow control
      - Provide a basic level of security
        for network access
      - Filter traffic based on traffic type
    - - Cisco routers support two types of ACLs
        
        Standard ACLs
        
        Extended ACLs
    - - An inbound ACL filters packets before they are routed to the outbound interface.
        
        An outbound ACL filters packets after being routed, regardless of the inbound interface.
- - - - To Match a Host
      - To Match an IPv4 Subnet
      - To Match an IPv4 Address Range
    - - To subtract the subnet mask from 255.255.255.255. Refer to the examples to learn how to calculate the wildcard mask using the subnet mask.
    - - Keywords reduce ACL keystrokes and make it easier to read the ACE.
        
        HOST- This keyword substitutes for the 0.0.0.0 mask. This mask states that all IPv4 address bits must match to filter just one host address.
        
        ANY - This keyword substitutes for the 255.255.255.255 mask. This mask says to ignore the entire IPv4 address or to accept any addresses.
- - - - Specifically, a router interface can have
        
        one outbound IPv4 ACL
        
        one inbound IPv4 ACL
        
        one inbound IPv6 ACL
        
        one outbound IPv6 ACL
        
        Assume R1 has two dual-stacked interfaces that require inbound and outbound IPv4 and IPv6 ACLs applied. As shown in the figure, R1 could have up to 8 ACLs configured and applied to interfaces. Each interface would have four ACLs; two ACLs for IPv4 and two ACLs for IPv6. For each protocol, one ACL is for inbound traffic and one for outbound traffic.