Understanding ACL
ACLs perform packet filtering to control the packets that move through the network. These controls allow to limit the network traffic and restrict the access of users and devices to the network. ACLs have many uses, and therefore many commands accept a reference to an access list in their command syntax. An ACL consists of one or more access control entries (ACE) that collectively define the network traffic profile.
Purpose of ACLs
ACLs allow you to perform the following:
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Filter incoming or outgoing packets on an interface.
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Restrict the contents of routing updates.
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Limit debug output that is based on an address or protocol.
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Control vty access.