Cisco’s IOS

Cisco’s IOS

Chapter 6 Objectives

• The Cisco router IOS• Enhanced editing• Administrative functions

– Hostnames– Banners– Passwords– Interface descriptions

• Verifying your configuration

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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

Connecting To A Cisco Router

Cisco 2800

Cisco 1841

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

Setup Mode

• Basic Management Setup

• Extended Setup

• Command-Line Interface

Configuration

• CLI Prompts

• Interfaces

• Sub-interfaces

• Line Commands

• Routing Protocol Configurations

Command-Line Interface (CLI)

• More flexible than setup mode.

• To use the CLI, just say No to entering the initial configuration dialog.

Subinterfaces

Allow you to create logical interfaces within the router

Router(config-if)#interface f0/0.1

Router(config-subif)#

Logging into the Router

• User mode: – Router>– Used mostly to view statistics

• Privileged mode:– Router#– Used to view & change router

configuration

Overview of Router Modes

• Global changes:– config terminal or config t– Changes made to running-config running-config

(DRAM)– To change the startup-configstartup-config (NVRAM)

• config memory or config mem

Note: Any configuration changes need to be placed into RAM. Typing config mem or config net (from a TFTP host) will append the current running-configrunning-config

Editing & Help Features

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 versionshow version

Enhanced Editing Commands

Enhanced Editing Commands (cont.)

Router Command History

Gathering Basic Routing Information

Administrative Functions

The administrative functions that you can configure on a router and switch are

• Hostnames• Banners• Password• Interface descriptions

Hostnames & Descriptions

• HostnamesRouter(config)#hostname todd

todd(config)#

• DescriptionsAtlanta(config)#int e0

Atlanta(config-if)#description Sales Lan

Banners

• Purpose

• Types– exec– incoming– login– motd

• Delimiting character

Setting the Passwords

• 5 passwords:– 1st two used to set your enable

password• Used to secure privileged mode;

Router>enable

– Other three are used to configure a password in useruser mode via:

• console port• auxiliary port• Telnet

Passwords

• Enable passwordsRouter(config)#enable password cisco

Router(config)#enable secret cisco

• Auxiliary Password

• Console Password

• Telnet Password

• Encrypting Your PasswordRouter(config)#service password-

encryption

Interface DescriptionsSetting 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.

Router Interfaces

• Bringing up an Interfaceno shutdownshutdownshow interface

• Configuring an IP Address on an Interface

Router(config)#int e0Router(config-if)#ip address 172.16.10.2

255.255.255.0Router(config-if)#no shut

• Serial Interface Commandsclock rate & bandwidth (entered in

kilobits)

Viewing, & Saving Configurations

• Viewing & Saving Configurations– running-configrunning-config saved in DRAM– startup-configstartup-config saved in

NVRAMcopy run start

sh run

sh start

erase startup-config

Verifying Your Configuration

Tools:– show running-config– show startup-config– ping– show cdp nei detail– trace– telnet

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

Summary

• Go through all the written labs and review questions

• Review answers in class

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