Exploration Network Chapter 11 (Rev 1.0)

7/29/2019 Exploration Network Chapter 11 (Rev 1.0)

1/42

2007 Cisco Systems, Inc. All rights reserved. Cisco PublicITE PC v4.0Chapter 1 1

Configuring and Testing

Your Network

Network Fundamentals Chapter 11


2/42

ITE PC v4.0Chapter 1 2 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Role of Internetwork Operating System (IOS)

The IOS file itself is several MB in size and is stored in asemi-permanent memory area called flash.


3/42


4/42


Configuration Files


5/42


Cisco IOS Modes Recognize that Cisco IOS is modal and describe the

implications of modes.


6/42


IOS Prompt Structure


7/42ITE PC v4.0Chapter 1 7 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

IOS Primary Mode Two primary modes: User EXEC and Privileged EXEC



Moving between the User EXEC and PrivilegedEXEC Modes

Output similar to a Cisco switch



Basic IOS Command Structure

Commands are not case-sensitive.

A command might require one or more arguments. Anargument is a value or variable defined by the user.

After entering each complete command, including anyarguments, press the key to submit thecommand to the command interpreter.



IOS Command Convention



Context-sensitive Help

IOS Help Forms: Context-sensitive help, Command,Syntax Check, Hot Keys and Shortcuts



Command Syntax Check


13/42


Hot Keys and Shortcuts

Tab - Completes the remainder of the command or keywordCtrl-R - Redisplays a line

Ctrl-Z - Exits configuration mode and returns to the EXEC

Down Arrow - Allows user to scroll forward through formercommands (Ctrl-N)

Up Arrow - Allows user to scroll backward through formercommands (Ctrl-P)

Ctrl-Shift-6 - Allows the user to interrupt an IOS process suchas ping or traceroute

Ctrl-C - Aborts the current command and exits the configuration

mode

Commands and keywords can be abbreviated to theminimum number of characters that identifies a uniqueselection.


14/42


IOS Examination Commands

Identify the purpose of the show command and severalof its variations


15/42


IOS Output show version


16/42


Other show outputs

show arp - Displays the ARP table of the device. show mac-address-table - (switch only) Displays the MAC

table of a switch.

show startup-config - Displays the saved configurationlocated in NVRAM.

show running-config - Displays the contents of the currentlyrunning configuration file

show ip interfaces - Displays IPv4 statistics for all interfaceson a router. To view the statistics for a specific interface,enter the show ip interfaces command followed by the

specific interface slot/port number. Another important formatof this command is show ip interface brief. This gets a quicksummary of the interfaces and their operational states.

When a --More-- prompt appears, press the Spacebar toview the next portion of output. To display only the next line,press the Enter key.


17/42


Other IOS Configuration Modes


18/42


Configuring Host Names

If the hostname is not explicitly configured, a routeruses the factory-assigned default hostname "Router."(Switch for a Cisco switch)

It is a good practice to create the naming convention at

the same time as the addressing scheme to allow forcontinuity within the organization.

Device host names are only used by administratorswhen they use the CLI to configure devices. Unless

configured to do so, the devices themselves do not usethese names when they discover each other andinteroperate.


19/42


Configuring Host Names

To negate the effects of a command, preface the commandwith the no keyword.


20/42


Limiting Device Access Passwords andBanners

Passwords are the primary defense againstunauthorized access to network devices.

The passwords introduced here are:

Console password - limits device access using the consoleconnection

Enable password - limits access to the privileged EXEC mode

Enable secret password - encrypted, limits access to theprivileged EXEC mode

VTY password - limits device access using Telnet

Use strong passwords that are not easily guessed.

In our labs, simple passwords such as cisco or classwill be used. These passwords are considered weakand easily guessable.


21/42


Configuring Console Passwords


22/42


Use Cisco CLI Commands to Perform BasicRouter & Switch Configuration and Verification

service password-encryption - causes the encryption of passwordsto occur when a password is configured. The command appliesweak encryption to all unencrypted passwords; weak encryption;irreversible


23/42


Banner MOTD

Because banners can be seen by anyone who attempts to log in,the message must be worded very carefully. Any wording thatimplies that a login is "welcome" or "invited" is not appropriate.


24/42


Checking Configuration Files


25/42


Backing Up Configurations Offline

Configuration files should be stored as backup files inthe event of a problem. Configuration files can bestored on a Trivial File Transfer Protocol (TFTP) server,a CD, a USB memory stick, or a floppy disk stored in asafe place. A configuration file should also be included

in the network documentation..


26/42


Backup Configurations with Text Capture(HyperTerminal)

Use a text file to backup and restore config settings


27/42


Configuring Router Ethernet Interfaces


28/42


Configuring Router Serial Interfaces


29/42


Interface Descriptions

Explain the purpose of assigning interface descriptionsto a router


30/42


Configuring Switch Interfaces


31/42


Test the Stack

Ping indicators: (!) - receipt of an ICMP echo reply; (.) -indicates a timed out while waiting for a reply; (U) -ICMP unreachable message


32/42


Interface Testing


33/42


Testing the Local NIC Assignment Use the ping command to determine if the IP protocol is

properly bound to an NIC


34/42


Testing Gateway Connectivity


35/42


Testing Remote Connectivity


36/42


Testing the Path to a Remote Host


37/42


Interpreting Test Results Identify several conditions that might cause the test to

fail


38/42


Use Common Utilities to Establish a RelativePerformance Baseline for the Network A baseline is a process for studying the network at regular intervals to

ensure that the network is working as designed. It is more than a singlereport detailing the health of the network at a certain point in time.

One method for starting a baseline is to copy and paste the results froman executed ping, trace, or other relevant command into a text file.


39/42


Use Common Utilities to Establish a RelativePerformance Baseline for the Network

Use the output of the traceroute command, saved intologs, and repeated over time, to establish relativenetwork performance


40/42


Learning About Nodes on a Network The arp command provides for the mapping of physical

addresses to known IPv4 addresses.

Another method for collecting MAC addresses is to employ aping sweep


41/42


Learning About Switched Connections One additional tool that can be helpful is a mapping of how

hosts are connected to a switch.


42/42

Date post:	04-Apr-2018
Category:	Documents
Upload:	yin0110yang
View:	223 times
Download:	0 times

Exploration Network Chapter 11 (Rev 1.0)

Documents