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Los Medanos CollegeLos Medanos College

Introduction to Cisco Network DevicesIntroduction to Cisco Network DevicesMark McGregor, InstructorApril, 2005

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Introduction to Cisco Introduction to Cisco Network Devices (ICND)Network Devices (ICND)

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What are ACLs?What are ACLs?

• ACLs are lists of instructions you apply to a router's interface to tell the router what kinds of packets to accept and what kinds to deny.

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How ACLs WorkHow ACLs Work

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Protocols with ACLs Protocols with ACLs Specified by NumbersSpecified by Numbers

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Creating ACLsCreating ACLs

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The Function of a Wildcard The Function of a Wildcard MaskMask

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Verifying ACLsVerifying ACLs

• There are many show commands that will verify the content and placement of ACLs on the router.–show ip interface –show access-lists–Show running-config

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Standard ACLsStandard ACLs

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Extended ACLsExtended ACLs

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Named ACLsNamed ACLs

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Placing ACLsPlacing ACLs

• Standard ACLs should be placed close to the destination.

• Extended ACLs should be placed close to the source.

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FirewallsFirewalls

A firewall is an architectural structure that exists between the user and the outside world to protect the internal network from intruders.

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Restricting Virtual Terminal Restricting Virtual Terminal AccessAccess