Sybex CCNA 640-802Chapter 4: Cisco’s IOS and SDM

Chapter 4 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– You should understand that routers are seldom

directly connected to user devices, such as workstations, printers, etc. Normally, a router is connected to another router, or it is connected to a switch (or a hub in an older environment) which is in turn connected to workstations or other devices found in an office.p. 173

Router Access (Connecting to a Cisco Router - 173)

• Console port (console)– Rollover cable (each end is a mirror-image o/t other)

• RJ-45 to DB-9• RJ-45 to DB-25

• Auxiliary port (AUX)– Can function like a console port– Or, can accept modem commands, i.e., from

sources outside the network (i.e., “out of band”)

• Virtual terminal (VTY)– This is for telnet access– This kind of access is from within the network (i.e.,

“in band”.

Connecting To A Cisco Router

Cisco 2811

Cisco 1841

Cisco ISR Routers

• Distinguish older Cisco routers from the newer, ISR routers

• The “Integrated Services Routers” line runs a “hardened” version of Linux and is generally deployed at branch offices.

• ISR routers are part of a trend to include more services in routers – probably making them more profitable.

Connecting To A Cisco Router

Connecting Via Terminal Programs• Establish a connection

– Physical connection through console• 9600 bits per second• data bits 8• stop bits 1• parity “none” • flow control “none”

– Logical connection through VTY – Terminal programs

• HyperTerminal, • Microphone Pro, • ProComm Plus, • Telix, • Tera Term

Bringing up a Router - pg 175

• 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)• i.e., the IOS is stored in a compressed state in non-

volatile memory, or NVRAM• When the router boots it is “decompressed” into RAM.

4: If a valid config is not found in NVRAM:• setupsetup mode mode

p. 177

Bringing up a Router - pg 175-76

• After the POST, some hardware information is listed. Specifically, memory information:

– Copyright (c) 1998-2003 by Boson Software

– C2500 platform with 20480 Kbytes of main memory [RAM]

– program load complete, entry point:0x8000080000, size:0x43b7fc

Self decompressing the image :

– ########################################

– ########################################

– ########################################

– ########################################

– ########################################

– ################# [OK]

– Cisco Internetwork Operating System Software

– IOS ™ C2500 Software (C2500-IK937S2-M), Version 12.3(20) Release software fc2 [IOS version]

– IOS (tm) 2500 Software(C2500-enterprise), Version 5.0, RELEASE SOFTWARE

– Copyright (c) 1998-2003 by Cisco Systems, Inc.

– -- some output omitted --

– Boson 2500 (BOSS) emulator (revision 5.0) with 20480K/512K simulated memory.

– BOSS, Version 5.0

– 1 Ethernet/IEEE 802.3 interface(s)

– 3 ISDN Basic Rate interface(s)7K bytes of simulated non-volatile configuration memory.

– 8192K bytes of simulated processor flash (Read/Write)

Bringing up a Router• Boot-up process:

Setup Mode

• Basic Management Setup

• Extended Setup

• Command-Line Interface

Command-Line Interface (CLI)

• More flexible than setup mode.

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

• Initial prompt consists of two parts– Hostname– Greater than symbol (>)

p. 179

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-configrunning-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-running-configconfig

p. 1

Configuration Modes

• Global configuration mode– Router(config)#

• Interface mode– Router(config–if)#

• Line configuration mode– Router(config-line)#

• Router configuration mode– Router(config-router)#

Configuration Modes

Configuration

• CLI Prompts

• Interfaces

• Sub-interfaces

• Line Commands

• Routing Protocol Configurations

Editing & Help Features

• Commands starting with a certain letterRouter#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• Passwords• Interface descriptions

Hostnames & Descriptions

• HostnamesRouter(config)#hostname todd

todd(config)#

• DescriptionsAtlanta(config)#int e0

Atlanta(config-if)#description Sales Lan

Banners

• Purpose: welcome message

• Types– exec: set EXEC process creation banner– incoming: set incoming terminal line banner– login: login banner– motd: set “Message of the Day” banner

• Delimiting character

Banners

Setting the Passwords

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

• Used to secure privileged mode; • Router>enable• Or Router>en (because no other commands at privileged level

. begin with “en”

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

• console port• auxiliary port• Telnet

Passwords• Enable passwords

– Router(config)#enable password cisco– Router(config)#enable secret cisco

Note: the secret password supersedes the enable password, i.e., if you set both passwords, you will be asked for the secret password.

• Auxiliary Password

• Console Password

• Telnet Password

• Encrypting Your PasswordRouter(config)#service password-encryption

Passwords

Passwords

Passwords

Passwords

Passwords

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 InterfaceRouter(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)

Configuring The Time And Date

Viewing, & Saving Configurations

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

copy 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 (layer 3 info)– Router#show ip interface– Router#show ip interface brief– Router#show controllers

Show Run command• Router# show run

• Version 12.1

• service timestamps debug uptime

• service timestamps log uptime

• no service password-encryption

• hostname Router

• ip subnet-zero

• !

• interface Serial0

• ip address 172.16.12.1 255.255.0.0

• no ip directed-broadcast

• clock rate 56000

• !

• interface Serial1

• no ip address

• no ip directed-broadcast

• shutdown

• !

• interface Ethernet0

• ip address 192.168.1.1 255.255.255.0

• no ip directed-broadcast

• !

• interface Ethernet1

• no ip address

• no ip directed-broadcast

• shutdown

• interface Bri0• no ip address• no ip directed-broadcast• shutdown• !• !• router igrp 1• network 192.168.1.0• network 172.16.0.0• !• ip classless• no ip http server• !• !• line con 0• transport input none• line aux 0• line vty 0 4• !• no scheduler allocate• end

Router Components

• ROM

• Flash memory

• NVRAM

• RAM/DRAM

Router Components

• ROM– Read-only memory (ROM)– Bootstrap program– ROM monitor firmware– ROM monitor mode

• (>) or (rommon 1>)

Router Components

• Flash memory– Erasable, programmable, read-only memory

(EPROM)– Contains the Cisco IOS– Can store multiple IOS– “show version” command (sh ver)– “show flash” command (sh fla)

Router Components

• NVRAM– Nonvolatile random access memory (NVRAM)– Special type of RAM– Not cleared when router is rebooted– Startup configuration file– “show start” command (sh sta)

Router Components

• Random access memory (RAM)– Volatile– Information is not retained during router reboot– Running configuration– “show running-config” command (sh ru)– “show memory” command (sh me)– “show buffers” command (sh buf)

Summary

• Go through all the written labs and review questions• Review answers in class

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