Access control lists are a set of rules which control network traffic and mitigates network attacks. The goal of Access Control Lists to filter traffic based on given filtering criteria. Access control lists are a set of rules that filter traffic in our networks as required by the security policy. You can implement only one access list on any interface.
Access lists are used by routers to deny or forward specific traffic from passing through some network interface. They manage the traffic when it passes through a switch. One access, lists may be configured, per direction, for each layer three protocol configured on an interface.
You can configure one access list, per direction, per layer 3 protocol
We can have only 1 access list per protocol, per direction and per interface. It means:
+ We can not have 2 inbound access lists on an interface
+ We can have 1 inbound and 1 outbound access list on an interface
