© Wiley Inc All Rights Reserved. CHAPTER 4: Introduction to the Cisco IOS CCNA: Cisco Certified Network Associate Study Guide

© Wiley Inc All Rights Reserved. The CCNA exam topics covered in this chapter include the following: Implementation & Operation Configure IP addresses, subnet masks, and gateway addresses on routers and hosts Configure a router for additional administrative functionality Implement a LAN Perform an initial configuration on a router Perform an initial configuration on a switch

© Wiley Inc All Rights Reserved. Cisco Router IOS Carries network protocols and functions Connects high-speed traffic between devices Adds security to control access Provides scalability for growth Supplies reliability

© Wiley Inc All Rights Reserved. Connecting To A Cisco Router

© Wiley Inc All Rights Reserved. Bringing up a Router Boot-up process: 1: POST 2: Looks for the Cisco IOS from Flash memory 3: IOS loads & looks for a valid configuration; startup-configstartup-config stored in nonvolatile RAM (NVRAM) 4: If a valid config is not found in NVRAM: setup modesetup mode

© Wiley Inc All Rights Reserved. Setup Mode Basic Management Setup Extended Setup Command-Line Interface

© Wiley Inc All Rights Reserved. Command-Line Interface (CLI) More flexible than setup mode. To use the CLI, just say No to entering the initial configuration dialog.

© Wiley Inc All Rights Reserved. Logging into the Router User mode: –Router> –Used mostly to view statistics Privileged mode: –Router# –Used to view & change router configuration

© Wiley Inc All Rights Reserved. Overview of Router Modes Global changes: –config terminal or config t running-config –Changes made to running-config (DRAM) startup-config –To change the startup-config (NVRAM) config memory or config mem running-config Note: Any configuration changes need to be placed into RAM. Typing config mem or config net (from a TFTP host) will replace the current running-config

© Wiley Inc All Rights Reserved. Configuration CLI Prompts Interfaces Sub-interfaces Line Commands Routing Protocol Configurations

© Wiley Inc All Rights Reserved. Editing & Help Features

© Wiley Inc All Rights Reserved. Editing & Help Features Commands starting with a certain letter Router#c? clear clock configure connect copy Enhanced Editing Commands Router-Command History Gathering Basic Routing Information –show version

© Wiley Inc All Rights Reserved. Enhanced Editing Commands

© Wiley Inc All Rights Reserved. Enhanced Editing Commands (cont.)

© Wiley Inc All Rights Reserved. Router Command History

© Wiley Inc All Rights Reserved. Gathering Basic Routing Information

© Wiley Inc All Rights Reserved. Administrative Functions The administrative functions that you can configure on a router and switch are Hostnames Banners Password Interface descriptions

© Wiley Inc All Rights Reserved. Hostnames & Descriptions Hostnames Router(config)#hostname todd todd(config)# Descriptions Atlanta(config)#int e0 Atlanta(config-if)#description Sales Lan

© Wiley Inc All Rights Reserved. Banners Purpose Types –exec –incoming –login –motd Delimiting character

© Wiley Inc All Rights Reserved. Setting the Passwords 5 passwords: –1st two used to set your enable password Used to secure privileged mode; Router>enable user –Other three are used to configure a password in user mode via: console port auxiliary port Telnet

© Wiley Inc All Rights Reserved. Passwords Enable passwords Router(config)#enable password cisco Router(config)#enable secret cisco Auxiliary Password Console Password Telnet Password Encrypting Your Password Router(config)#service password-encryption

© Wiley Inc All Rights Reserved. Interface Descriptions Setting descriptions on an interface is helpful to the administrator and, like the hostname, only locally significant. The description command is a helpful one because you can, for instance, use it to keep track of circuit numbers. Here’s an example: Atlanta(config)#int e0 Atlanta(config-if)#description Sales Lan Atlanta(config-if)#int s0 Atlanta(config-if)#desc Wan to Miami circuit:6fdda4321 You can view the description of an interface either with the show running-config command or the show interface command.

© Wiley Inc All Rights Reserved. Router Interfaces Purpose Bringing up an Interface no shutdown shutdown show interface Configuring an IP Address on an Interface Router(config)#int e0 Router(config-if)#ip address Router(config-if)#no shut Serial Interface Commands clock rate & bandwidth (entered in kilobits)

© Wiley Inc All Rights Reserved. Viewing, & Saving Configurations Viewing & Saving Configurations –running-config –running-config saved in DRAM –startup-config –startup-config saved in NVRAM copy run start sh run sh start erase startup-config

© Wiley Inc All Rights Reserved. Verifying Your Configuration Tools: –show running-config –show startup-config –ping –show cdp nei detail –trace –telnet

© Wiley Inc All Rights Reserved. Other Verification Methods Verifying with the show interface command –Router#show interface ? Verifying with the show ip interface command –Router#show ip interface –Router#show ip interface brief –Router#show controllers