What are ACLs?
ACLs (Accsess Control Lists) have multiple uses.
Controls which devices have access to certain parts of the network.
ACLs funtion as a packet filter, instructing the router to permit or discard specific traffic.
ACLs can filter traffic based on source/destination IP addresses, source/destination Layer 4 ports, etc.
Requirements
Hosts in 192.168.1.0/24 can access the 10.0.1.0/24 network.
Hosts in 192.168.2.0/24 cannot access the 10.0.1.0/24 network.
ACLs are configured globally on the router. (global config mode)
They are an ordered sequence of ACEs. (Access Control Entries)
ACL1:
if source IP = 192.168.1.0/24, then permit
if source IP = 192.168.2.0/24, then deny
source IP = any, then permit
Configuring an ACL in global config mode will not make the ACL take effect.
The ACL must be applied to an interface.
ACLs are applied either inbound or outbound.
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