Chapter 11- Configuring and Testing Your Network

Modified by Profs. Chen and Cappellino

Objectives Learning Objectives

Upon completion of this chapter, you will be able to:

Define the role of the Internetwork Operating System (IOS).

Define the purpose of a configuration file.

Identify several classes of devices that have the IOS embedded.

Identify the factors contributing to the set of IOS commands available to a device.

Identify the IOS modes of operation. Identify the basic IOS commands. Compare and contrast the basic

show commands.

Cisco IOS Routers, switches and other Cisco devices cannot function

without an operating system. The Cisco Internetwork Operating System (______) is the

________________________________________Provides the following services:

The IOS operates differently depending on different devices, the device's purpose and _________________

The IOS file itself is several megabytes in size and is stored in a memory area called _________________.

____________ of flash memory are _______________________________ Using flash memory _____________________________________ to newer

versions or to have new features added. The _____________________________________________ and

runs from RAM when the device is operating. The services provided by the Cisco IOS are accessed using

a command line interface (_____________).

Cisco IOS Access Methods: Console

The CLI can be accessed through a __________ __________, also known as the ____________

Console uses a low speed _______________ to directly connect computer to console port on the router or switch.

The ________________________________ that provides _______________ to a router.

The console port ________________________ ________________________ on the device.

Console port used for the following: The __________________ of the network device__________________________ and when remote

access is not possible_________________________ procedures

The console should be ___________________ _____________________ to prevent unauthorized device access.

3 ways to access the CLI: –Console

–Telnet or SSH

–AUX port

Console cont… Initial startup of Cisco routers

Take the following steps to connect a terminal to the console port on the router: • Connect the terminal using a rollover cable with an RJ-45 to DB-9 adapter. • Configure the terminal or PC terminal emulation software for 9600 baud, 8 data

bits, no parity, 1 stop bit, and no flow control.

Rollover cable

Console port

Com1 or Com2 serial port

Terminal or a PC with terminal emulation software

Router

Console cont… Initial startup of Cisco routers

Note: A console connection is not the same as a network connection!

=

Cisco IOS Access Methods: Telnet and SSH Telnet is a method for _____________

______________________________Telnet sessions _____________________ and at

least _______________________ configured with a Layer 3 address

Host with a telnet client can access the ________ sessions on the Cisco device.

The IOS _____________________ that the Telnet session use a _____________________

Secure Shell (________) protocol is a _____________ method for __________ ______________________

Remote login ______________ but more secureProvides ____________________________ than

Telnet and uses ______________________ when transporting session data.

Most newer versions of the IOS contain an SSH server.

Unfortunately, SSH client software is by default, not provided on client computer operating systems

Cisco IOS Access Methods: AUX A way to establish a CLI session

__________________________ connection using a modem connected to the router's ____________________

This method also does ________________ ___________________________ to be configured or available on the device.

AUX port can also be used locally, like the console port, with a direct connection to a computer running a terminal emulation program.

Only used locally when there are problems using the console port

The console port is required for the configuration of the router and is the preferred port for troubleshooting

Not all routers have an auxiliary port.

Configuration Files Network devices depend on ___________________ for their

operation: __________________ and ________________ The operating system facilitates the ___________________________

__________________________________Configuration files contain the ______________________________

_____________________________________________ A Cisco network device contains ______ configuration files:

The ___________________________ - used during the __________ ____________________________________

________________________, it is used to operate the device. _____________ to the running configuration will ___________________________

of the Cisco device. After making any changes, those changes should be saved back to the startup-

config file so that they will be available next time the device restarts. The running configuration is _____________________________

The ______________________ - used as the ________ configuration and is ________________________________________

_____________________ so it remains intact when the device is powered down __________________ each time the router is started or reloaded. ________________ into RAM, the startup config is ________________________

configuration.

Graphic: Relationship between NVRAM and RAM

Cisco IOS Modes The Cisco IOS is an operating system which uses

_______________, each mode having its own particular operation.

The CLI uses a hierarchical structure for the modes. In order from top to bottom, the major modes are:

____________________ mode________________________ mode______________________________ mode_____________________ specific configuration modes

Each mode accomplishes particular tasks and has specific commands that are available in that mode.

Each mode uses a ________________________For example, to configure a router interface, the user must

enter interface configuration mode. All configurations that are entered in interface configuration mode

apply only to that interface. Different authentication can be required for each

hierarchal mode.

Cisco IOS Modes cont…

Cisco IOS Modes: Command Prompts When using the CLI, the mode is

_______________________ ________ that is unique to that mode.

The word prompt is used because the system is prompting you to make an entry.

By default, every prompt ______ with the _______________

Following the name, the remainder of the prompt indicates the mode.

For example, the default prompt for the global configuration mode on a router would be:

Router(config)# As commands are used and

modes are changed, the ______ __________________________ context.

1

Cisco IOS Modes: Primary Modes Cisco IOS software separates the

EXEC sessions into two access modes.

___________ Mode Switch__ or Router__

This mode is the first entrance into the CLI of the router.

The user EXEC mode allows only a _________ _______________________

Often referred to as ____________________ since ___________ to the configuration are _________

Identified by the > symbol at the end of the prompt By default, there is no authentication required but

for security sake should be used

IOS Modes: Primary Modes cont. Privileged EXEC Mode Switch____

or Router_____

Also called “_____________” Allows more commands to be executed. Allows the ___________________________

____________________________ ______________________________ in this mode

The privileged EXEC mode can be identified by the prompt ending with the # symbol.

By default, does not require authentication but it should be configured and used.

Global configuration mode and all other more specific configuration modes can only be reached from the privileged EXEC mode.

Moving between the User EXEC and Privileged EXEC Modes

The _________________ commands are used to _____________________ mode and ______________ mode.

In order to access privileged EXEC mode, use enable command.

Router>enableOnce <Enter> is pressed, the router prompt changes to:

Router# The # at the end of the prompt indicates that the router is

now in privileged EXEC mode. If password authentication has been configured for the

privileged EXEC mode, the IOS prompts for one: Router>enable Password: Router#

The disable command is used to return from the privileged EXEC to the user EXEC mode.

For example: Router#disable Router>

Basic IOS Command Structure Each IOS ______________________

___________________ and is executed at the appropriate prompt.

The commands are _________________. Following the command are one or more

keywords and arguments. For example:

Switch#show running-config The command show is followed by the keyword

running-config which displays the running-configuration as output

Switch(config-if)#description GCC Campus Switch

The command is: description. The user defined argument is GCC Campus Switch

Pressing the <Enter> key submits the command

Note the command convention used by Cisco…

Using CLI Help: Context-Sensitive Help The context-sensitive ________

_________________________ and the arguments associated with those commands within the context of the current mode.

To access, enter a question mark, __, at any prompt.

No need to strike the <Enter> key. Uses:

When unsure of the name for a command or want to see a __________________________

Display a list of commands ________ _________________________

Determine which options, arguments etc are matched with a specific command

The IOS has several forms of help available:

–Context-sensitive help

–Command Syntax Check

–Hot Keys and Shortcuts

Using CLI Help cont : Command Syntax Check When a command is submitted by

pressing the <Enter> key, the command line interpreter parses the command from left to right to determine what action is being requested.

If the interpreter understands the command, the requested action is executed.

if the interpreter cannot understand the command being entered, it will provide feedback describing what is wrong with the command.

There are ________ different types of _____________________:

___________ command Not enough characters to recognize the command

___________ command Good start on the command, but needs more

argument__________ command

Part or the whole command is wrong

Using CLI Help cont : Hot Keys and Shortcuts

The CLI offers a number of hot keys and shortcuts make configuring, monitoring faster and easier.

There are a bunch listed in the curriculumYou should be aware of

them- you’ll find you have some favorites…

IOS “Examination” Commands Verify and troubleshoot network operation using

a variation of the examination command: show How would you output a list of available show

commands?

IOS “Examination” Commands cont..

show interfaces_____________________________ on the device. To view the statistics for a specific interface, enter the show interfaces command followed by the specific interface slot/port number.

Router#show interfaces serial 0/1 show version

Displays ___________________________________ ______________, along with hardware information.

Software Version - IOS software version (stored in flash) Bootstrap Version - Bootstrap version (stored in Boot ROM) Software image name - IOS filename stored in flash Router Type and Processor type - Model number and processor type Hardware Interfaces - Interfaces available on router Configuration Register - Sets bootup specifications, console speed

setting, and related parameters. ETC..

IOS “Examination” Commands cont.. show arp - Displays the ________ of the device. show mac-address-table - (_______ only)

Displays the __________________ show startup-config - Displays the ________

______________ located in ____________. show running-config - Displays the contents of

the ____________________ file or the configuration for a specific interface, or map class information.

show ip interfaces - Displays _____________ ________________ on a router.

show ip interface brief - This is useful to get a quick summary of the interfaces and their operational state.

Commonly used

IOS Configuration Modes Global Configuration Mode

AKA ___________ modeChanges made in this mode _____ _____________________________________________________

Use the following command to get from privileged EXEC mode to the global configuration mode:

Router#_______ __________Once the command is executed, the prompt changes to show that the router is in global configuration mode.

Router(config)#

IOS Configuration Modes cont… Specific Configuration Modes

There are many different configuration modes each of which configures a particular function.

To exit a specific configuration mode and return to global configuration mode, enter ______ at a prompt.

To leave a specific configuration mode and _________________________, enter _____ or ___________

Best practice After a change has been made, save to the

running-config to startup-config to prevent loss of changes

Router#copy running-config startup-config

Devices Need Names The hostname is seen in CLI prompt of each router

or switch Router’s factory-assigned default hostname "Router." Switch’s factory-assigned default hostname, "Switch."

So as to avoid confusion, __________________ ______________________ to each device following company’s naming conventions such as:

Start with a letterEnd with a letter or digitHave characters of only letters, digits, and dashes

Hostnames ______________________

Applying Names Once the naming convention has been

identified, the next step is to apply the names to the router using the CLI.

Router#configure terminalRouter(config)#Router(config)#hostname AtlantaHQAtlantaHQ(config)#

Notice that the hostname appears in the prompt.

To negate the effects of a command, ________________________________________________________

Example, to remove the hostname of a device, use:

AtlantaHQ(config)# no hostname Router(config)#

Default hostname is back…

Limiting Device Access – using Passwords Passwords are the primary defense against unauthorized access to

network devices.The passwords which can be used are:____________________ - limits access using the console connection_____________________ - limits access to the ________________ mode______________________ - ______________________, limits access to

the _______________________ mode______________________ - limits device access using Telnet

As good practice, use ______________________________ for each of these levels of access.

The use of easily guessed passwords is a security issue. Consider these key points when choosing ___________________________ passwords:

Use passwords that are more than 8 characters in length.Use a combination of upper and lowercase and/or numeric sequences in

passwords.Avoid using the same password for all devices.Avoid using common words which are easily guessed.

Note: In most of the labs, we will be using simple passwords such as cisco or class.

These weak passwords can be easily guessed and should not be used in a production environment.

Limiting Device Access – Console Password The console port of a device must be

secured with a strong password. The following are used to set a

password:Switch(config)#line console 0

The zero is used to represent the first (and in most cases only) console interface for a router.

Switch(config-line)#password password password password specifies a password.

Switch(config-line)#__________ The login command configures the router

_______________________________ When login is enabled and a password set, there

will be a prompt to enter a password. Once these three commands are executed, a

password prompt will appear each time a user attempts to gain access to the console port.

For security, when prompted for a password, the ______________________________ ___________________________________

Limiting Device Access – Enable and Enable Secret Passwords

To provide additional security, use enable password or _____________ command to establish authentication before accessing __________________ (enable) mode.

Best to use the enable secret command as it uses encryption for more robust security

“enable password” command is older and is not encrypted

The following commands are used to set the passwords:

Router(config)#enable password passwordRouter(config)#enable secret password

If no enable password or enable secret password is set, the _____________________ _____________________________________

Without an enable password having been set, attempting to use a Telnet session would trigger the following message:

% No password set

Enable and Enable Secret Password example:

Limiting Device Access – VTY Password The vty lines allow access to a router

via Telnet. By default, Cisco devices generally support

______________________________A password needs to be set ____________. The same password _________ be set for

all connections or unique passwords can be set for some or all lines

The following commands are used to set a password:

Router(config)#line vty 0 4Router(config-line)#password passwordRouter(config-line)#_____________

By default, the IOS includes the “_____” command on the VTY lines which prevents Telnet access to the device without first requiring authentication.

Encrypting Password Display Another useful command

________________________________________________________________________________

This is the __________________ ________________ command.

This command causes the encryption of passwords to occur when a password is configured.

When viewing the configuration file, all passwords will then be encrypted

Once the encryption has been applied, removing the encryption service does not reverse the encryption.

Limiting Device Access – _______ Messages Provides _______________________________

___________________________________________________ into that device

Banners can be an important part of the legal process in the event that someone is prosecuted for breaking into a device.

Some examples information to include in a banner:

"Use of the device is specifically for authorized personnel."

"Legal action will be pursued for any unauthorized use."

The IOS provides multiple types of banners. One common banner is the message of the day (__________________).

Configured in _________________Requires the use of delimiters at the beginning and

end of the message to identify the content of the banner message.

Lines of text are entered to represent the banner message.

Switch(config)#banner motd # message #

Note needed spaces between message and delimiting character

Managing Configuration Files After making changes to a

configuration, consider 3 options: 1. Make the Changed Configuration the New Startup Configuration

Where is the running configuration stored?

Saving the ____________________ ______________________________________________________ as the new startup configuration.

Be sure to verify changes before savingSwitch# copy _____________ _______________________

Saves the changes to the config file

Managing Configuration Files cont..2. Return the Device to Its Original Configuration

If changes made to the running configuration do not have the desired effect, it is necessary to restore the previous configuration.

Assuming that we have not overwritten the startup configuration with the changes, we can replace the running configuration with the startup configuration

_________________________________________ command.

When initiating a reload, a prompt will appear to ask whether to save the changes made. To ___________________________

Router#reload

System configuration has been modified. Save? [yes/no]: n

Proceed with reload? [confirm]

*Apr 13 01:34:15.758: %SYS-5-RELOAD: Reload requested by console. Reload Reason:

3. Removing All ConfigurationsIf undesired changes were saved to the ______________, this requires _____________ configuration and _______________________Router# erase startup-config Reloads the device to remove the current running configuration file and blanks the router

Backing Up Configurations Offline Configuration files should be stored as

backup files in the event of a problem. Configuration files can be stored in a safe

place on a Trivial File Transfer Protocol (___________) server, a _____ memory stick etc.

A configuration file should also be ___________________________

Backup Configuration on TFTP ServerUse either the copy running-config tftp or

copy startup-config tftp command and follow these steps:

1. Enter the copy running-config tftp command. 2. Enter the IP address of the host where the

configuration file will be stored. 3. Enter the name to assign to the configuration

file. 4. Answer yes to confirm each choice

Backup Configurations with Text Capture (HyperTerminal)

Configuration files can be ____________ __________________ for later use.

When using _______________, follow these steps:

1. On the Transfer menu, click Capture Text.2. Choose the location. 3. Click Start to begin capturing text. 4. Once capture has been started, execute the

show running-config or show startup-config command at the privileged EXEC prompt. Text displayed in the terminal window will be placed into the chosen file.

5. Stop the capture process6. View the output to verify that it was not

corrupted.

Restoring Text Configurations A configuration file can be copied from storage

to a device. When copied into the terminal, the IOS executes each line of the configuration text as a command.

_________________________________ to ensure that encrypted passwords are in plain text and that non-command text such as "--More--" and IOS messages are removed.

At the CLI, the device must be set at the global configuration mode to receive the commands from the text file being copied.

When using HyperTerminal, the steps are:1. Locate the file to be copied into the device and

open the text document.2. Copy all of the text.3. On the Edit menu, click paste to host.

The text in the file will be applied as commands in the CLI and become the running configuration on the device. Remove

Configuring Interfaces on a router Interface configuration is ____________________

So far commands have been generic Each interface on a router has its own unique IPv4

address.The address assigned to each interface exists in a separate network devoted to the interconnection of routers.

Configuring Interfaces: Ethernet Interfaces

Router ____________________________ ___________________________________ directly connected to the router.

Each Ethernet interface must have an ______________________ to route IP packets.

To configure an Ethernet interface follow these steps:

Router#config t Router(config)#interface FastEthernet 0/0 Router(config-if)#ip address ip_address

subnetmaskRouter(config-if)#no shutdown

The “____________________” command enables the Interface

By default, interfaces are disabled. If an interface needs to be disabled for

maintenance or troubleshooting, use the shutdown command.

Configuring Interfaces: Serial Interfaces _____________________________________

_____________________________Each connected serial interface must have an

__________________________________ to route IP packets.

Configure the IP address with the commands:Router#config t Router(config)#interface Serial 0/0 Router(config-if)#ip address ip_address

subnetmask Serial interfaces ____________________ to

control the timing of the communications. In most environments, a DCE device such as a

CSU/DSU will provide the clock. By default, ________________________, but

they can be configured as DCE devices. On serial links that are directly interconnected,

as in our lab environment, one side must ________________________________ signal:

Router(config-if)#clock rate 56000 Router(config-if)#no shutdown

Done on router’s side with DCE cable

* 56000 is clock rate value used in lab*

Configuring Interfaces: Description of an Interface A ___________________________________

______________________ should be part of the configuration of each interface.

The interface description will appear in the output of these commands: show startup-config, show running-config, and show interfaces.

Example- description listing locations connected to int. Interface F0/0 is connected to the mail switch in the admin building

To create- use the command _______________ ___________________ and the description detail

HQ-switch1# configure terminal HQ-switch1(config)#interface fa0/1 HQ-switch1(config-if)#description Connects to main switch in Building A

Configuring a Switch Interface A LAN switch is an _____________ where

the ___________________ _____________ _________________________________

________________________________________________________________________.

Switch interfaces (ports) are enabled by default

Descriptions can be assigned To be able to _____________________, an

________________________________Switch then acts like a host device Address for a switch is assigned to a Virtual

LAN interface (VLAN)- usually __________ Enable this interface with no shutdown

command. Like any other host, the ________________

__________________________ to communicate outside of the local network.

Assign the gateway with the ip default-gateway command.

1

Only needed for the management traffic, but not for the regular data frame forwarding.

Test The Stack: The Ping Command Recall: What does Ping do? Ping is used to _________________________________

When troubleshooting, use an _______________________ starting with the ________________________ and then ________to the _________ and, finally, to __________________

By using the ping command in this ordered sequence, problems can be isolated.

IOS Ping IndicatorsA ping from the IOS will yield to one of several indications for each

ICMP echo that was sent. The most common indicators are: _____- indicates receipt of an ICMP echo reply- _____________ _ - indicates a _______ while waiting for a reply- issues/security block ____ - an ICMP ___________ message was received

Testing the Loopback- recall- What is the loopback?As a first step to verify the IP configuration on the local host. C:\>ping 127.0.0.1

Test The Router Interface Assignment

Verifying the Router InterfacesOne of the most used commands is show ip interface brief

Provides a summary of the key information for all the interfaces including the IP address, if any, assigned to each interface and the operational status of the interface.

We will see an example on the following slide….notice… The _____ in the ______ column shows it is __________________ The ______________________________ shows that the _______

______________________________

Testing Router ConnectivityConnectivity of a router can also be tested with the ping and traceroute commands.

Test The Router Interface graphic…

Test The Switch Interface Assignment Verifying the Switch Interfaces

____________________ brief used to verify the switch interfaces as well as router’s

Recall: the IP address for the switch is applied to a VLAN interface and it’s status will also show

A ____________________________________________ to the interface or the network interface of the devices that is connected is not operational.

An interface is considered _________________________________ ____________________________________

Testing Switch ConnectivityLike other hosts, the switch can test its Layer 3 connectivity with the ping and traceroute commands.

Note the following important facts… An ___________________________ for a switch to perform its job

of frame forwarding and The ___________________ to communicate outside its local

network.

Test The Switch Interface graphic…

Test The Interface Assignment So far we have talked about how

to test the router and the switch The next step in the testing

sequence is to ______________ ____________________________________________ and that the NIC is ready to transmit signals across the media.

Ping the IP address of the host device itself

If this test ______, it is likely that there are __________________ ___________________________ and may require reinstallation of either or both.

Testing hosts on the Local Network Successfully pinging remote hosts

verifies that __________________ ______________________________ (* May not work in XP *)

Possible failure messages include: Destination Unreachable, . Request Timed Out.- indicating that no

response was made to the ping attempt

Extended Ping (Entered at router prompt)

Allows ping to be customized with more options for use in troubleshooting

Example: Assigning longer timeout periods would

indicate a possible latency issue

Testing Gateway and Remote Connectivity The next step in the testing sequence is

to use the ping command to _______ ________________________ address.

Recall: the ______________________ ____________________ so communication with the gateway is important

To discover the gateway IP address use the ipconfig command at the command prompt

If the gateway test fails, _______________________ ensure that

the proper address is being tested. If all devices are configured properly, check

the _______________ to ensure that it is secure and properly connected.

Testing Gateway and Remote Connectivity Once verification of the local LAN and gateway is

complete, testing can proceed to ____________. As seen in the graphic, verification tests should

begin within the local network and progress outward to the remote devices.

First, the ___________________ of the local network gateway router.

Then, ___________________________________Last, test the communication to the remote network

by _____________________________________ ______________________

If you cannot ping at any point, first _________ _________________ using the show ip route command

If there is no route to reach this network, you will need to identify why the route does not exist- check for configuration issues.

NOTE: ping will not always help identify the cause of a problem but can give direction in the troubleshooting process.

Recall- ping can be blocked at any point along the way

1. 2.3.

4.

#1-4 indicate ping process…

Tracing and Interpreting Trace Results The next step in the testing is to

____________________returns a list of hops as a packet is routed through a network.

When performing the trace from ______________, use ___________.

When performing the trace from __________ CLI, use ____________.

A trace command can show the path of the last successful communication and help isolate the problem

Example-- C:\>tracert 10.1.0.2 from the Windows cmd prompt

Example-- RouterA#traceroute 10.1.0.2 from the router’s CLI

Network Baselines One of the most effective tools for monitoring and

troubleshooting network performance is to establish a ____________________________

The ________________________________________ __________________________________

Consists of an _______________________________________ _____________________________

Measuring performance at varying times and loads will assist in creating a better picture of overall network performance.

Baseline reports can consist of _______________ _____________________________________

To obtain a list of MAC to IP address mapping, use arp To see a mapping of hosts on a switch, use the command: #show mac-address-table

Network Baselines cont…

Run the _________________ _________ and save the data each time.

An examination of the files will begin to reveal ______________ in network performance and provide the baseline for future troubleshooting. Note issues such as reoccurring error messages, response

times from host to host etc

Data generated using either the computer prompt or the router prompt can contribute to the baseline.

_____________________ is vitally important and key!!