z Configuring a Network Operating z System z · Configuring a Network Operating ... Establishing a HyperTerminal session Rollover cable Console port ... • Tera Term • SecureCRT

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Configuring a Network Operating Systemy

Objectives

Explain the purpose of Cisco IOS.Explain how to access and navigate Cisco IOS to configure network devices.Describe the command structure of Cisco IOS software.Configure hostnames on a Cisco IOS device using the CLI.Use Cisco IOS commands to limit access to device configurations.Use Cisco IOS commands to save the running configuration.Explain how devices communicate across network media.Configure a host device with an IP address.Verify connectivity between two end devices.

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Cisco IOSOperating Systems

All networking equipment depend on operating systems:End users (PCs laptops smart phones tablets)End users (PCs, laptops, smart phones, tablets)SwitchesRoutersWireless access pointsFirewalls

Cisco Internetwork Operating System (IOS)Collection of network operating systems used on Cisco devices

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Cisco IOS

Operating Systems

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Cisco IOS

Purpose of OS

PC ti t (Wi d 8 Li & OS X) f t h i lPC operating systems (Windows 8, Linux & OS X) perform technical functions that enable • Use of a input and output devices• Manage processes and programs• Manage file systems, security, hardware, etc.

Switch or router IOS provides options to • Same functions as host operating systems• Configure interfaces• Enable routing and switching functions

All networking devices come with a default IOS (switches, routers, firewalls)Possible to upgrade the IOS version or feature set 5

Cisco IOS

Location of the Cisco IOS

IOS stored in FlashNon-volatile storage – not lost when power is lostCan be changed or overwritten as neededCan be used to store multiple versions of IOSIOS copied from flash to volatile RAM when bootedQuantity of flash and RAM memory determines IOS that can be used

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Cisco IOS

IOS FunctionsMajor functions performed or enabled by Cisco routers and switches include:

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Router/Switch Bootup Process (more in later course)

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Bootup Process

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running-configIOS (running)

startup-config IOSios (partial)Bootup program

Where is the permanent configuration file stored used during boot-up? NVRAM (B)Where is the diagnostics software stored executed by hardware modules? ROM (D)

Where is the backup (partial) copy of the IOS stored? ROM (D)

Where is IOS permanently stored before it is copied into RAM? FLASH (C)

Where are all changes to the configuration immediately stored? RAM (A)

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A B C D

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startup-config

IOS

Bootup program

ios (partial)

running-config

IOS (running)

A B D

B A D

C D A

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A B C D

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Accessing a Cisco IOS DeviceConsole Access Method

Most common methods to access the Command Line InterfaceConsoleTelnet or SSHAUX port

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Accessing a Cisco IOS Device

Console Access Method

C l tConsole portDevice is accessible even if no networking serviceshave been configured (out-of-band)Need a special console cable (aka rollover cable)Allows configuration commands to be enteredShould be configured with passwords to prevent unauthorized accessDevice should be located in a secure room so console port can not be easily accessed

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Establishing a HyperTerminal session

Rollover cable

Console portTerminal or a PC with terminal

Router

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Connect PC using the RJ-45/mini-USB to Serial/USB rollover cable. Configure the terminal or PC terminal emulation software for:

9600 baud8 data bitsno parity1 stop bitno flow control

Com1 or Com2 serial port Or USB port with USB-to-Serial adapter

emulation software

Terminal (Serial) Settings)

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Configure the terminal or PC terminal emulation software for: 9600 baud8 data bitsno parity1 stop bitno flow control.

Establishing a Terminal/Serial/Console session

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

• PuTTY• Tera Term• SecureCRT• HyperTerminal• OS X Terminal• Zoc

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Dumb Terminal


Telnet, SSH, and AUX Access MethodsTelnet

Method for remotely accessing the CLI over a networkRequire active networking services and one active interface that is configured

Secure Shell (SSH) – Preferred over TelnetRemote login similar to Telnet but utilizes more securitySt d th ti tiStronger password authenticationUses encryption when transporting data

Aux Port (not used too much)Out-of-band connectionUses telephone lineCan be used like console port

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C:\> ssh

C:\> ping

Ethernet ConnectionNetwork connection needed

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When can you use a network connection to connect to the router?

What software/command do you need?

What cable and ports do you use?

When should you not use a network connection to configure the router?

When there is a network connection to the router (telnet).

TCP/IP, Terminal prompt (DOS), Tera Term, etc.

PC & Router: Ethernet NICEthernet straight-through cable

When the change may disconnect the telnet connection.

NIC


Terminal Emulation Programs

Software available for connecting to a networking device (usually same as terminal/serial/console connection):

PuTTYTera TermSecureCRTHyperTerminalOS X TerminalZoc

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Navigating the IOSCisco IOS Modes of Operation

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Navigating the IOS

Cisco IOS Modes of Operation

enable

configure terminal

interface < >router < >line < >line < >

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Navigating the IOS

Primary Modes

enableenable

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Navigating the IOS

Global Configuration Mode and Submodes

Global configuration mode and interface configuration modes can only be reached from the privileged EXEC mode. 24

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Navigating the IOS

Navigating between IOS Modes

Similar IOS commands for switches and routers25

Navigating the IOS

Navigating between IOS Modes (cont.)Switch> user modeSwitch> enable go to privilege mode Switch# configure terminal go to global configuration

modeSwitch(config)# interface vlan 1 go to interface modeSwitch(config-if)# exitSwitch(config)# exitSwitch# config t Shortened commands and parametersSwitch(config)# vlan 1 go to VLAN configuration modeSwitch(config-vlan)# end go to privilege-EXEC mode Switch# disable Switch> enableSwitch# config t Switch(config)# line vty 0 4 go to interface (line) modeSwitch(config-line)# exitSwitch(config)#

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Common Commands for Switches and RoutersSwitch> user modeSwitch> enableSwitch# privilege mode

Switch# configure terminalSwitch(config)# exitSwitch# config t

Switch(config)# hostname name

Switch(config)# enable secret password privilege password

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g p p g pSwitch(config)# line console 0 console passwordSwitch(config-line)# password passwordSwitch(config-line)# loginSwitch(config)# line vty 0 4 telnet passwordSwitch(config-line)# password passwordSwitch(config-line)# login

Switch(config)# banner motd # message # banner

Switch(config)# interface type number configure interfaceSwitch(config-if)# description description

Making your life easier!

Switch# enableSwitch(config)# line console 0 Console portSwitch(config-line)# logging synchronous IOS will notSwitch(config-line)# exec-timeout 0 0 passwordSwitch(config)# no ip domain-lookup passwordSwitch(config-line)# login

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Switch(config)# banner motd # message # banner

Switch(config)# interface type number configure interfaceSwitch(config-if)# description description

Navigating the IOS

Navigating between IOS Modes

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The Command StructureIOS Command Structure

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The Command Structure

Cisco IOS Command ReferenceIOS Command ConventionsThe general syntax for a command is the command followed by any appropriate keywords (defined) and arguments (undefined). An argument is generally not a predefined word. An argument is a value or variable defined by the user.

Switch(config-if)# description string

Boldface text indicates commands and keywords that are typed as shown Italic text indicates an argument for which you supply the value. For the description command, the argument is a string value. The string value can be any text string of up to 80 characters.Example:

Switch(config-if)# description MainHQ Office Switch

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Cisco IOS Command ReferenceFor the ping command:

Switch> ping IP-addressSwitch> ping 10.10.10.5

The command is ping and the user defined argument is the 10.10.10.5.

Similarly, the syntax for entering the traceroute command is:Switch> traceroute IP-addressSwitch> traceroute 192.168.254.254

The command is traceroute and the user defined argument is the 192.168.254.254.

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Context Sensitive Help

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Command Syntax Check

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Hot Keys and ShortcutsTab - Completes the remainder of a partially typed command or keywordCtrl-R - Redisplays a lineCtrl-A – Moves cursor to the beginning of the lineCtrl-Z - Exits configuration mode and returns to user EXECD A All th t ll f d th h fDown Arrow - Allows the user to scroll forward through former commandsUp Arrow - Allows the user to scroll backward through former commandsCtrl-Shift-6 - Allows the user to interrupt an IOS process such as ping or traceroute. Ctrl-C - Aborts the current command and exits the configuration mode

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IOS Examination Commands

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The show version Command

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Navigating the IOS

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HostnamesWhy the Switch

Let’s focus on Creating a two PC network connected via a switchSetting a name for the switchLimiting access to the device configurationConfiguring banner messages Saving the configuration

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Hostnames

Device NamesHostnames allow devices to be identified by network administrators over a network or the Internet.Some guidelines for naming conventions are that names should:

Start with a letterContain no spacesEnd with a letter or digitUse only letters, digits, and dashesBe less than 64 characters in length

Without names, network devices are difficult to identify for configuration purposes.

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Hostnames

Configuring Hostnames

Switch(config)# hostname Sw-Floor-3Sw-Floor3(config)#



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Limiting Access to Device ConfigurationsSecuring Device AccessThe passwords introduced here are:

Enable password - Limits access to the privileged EXEC mode

Enable secret - Encrypted, limits access to the privileged EXEC mode

Console password - Limits device access using the console connection

VTY password - Limits device access over Telnet

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

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Limiting Access to Device Configurations

Securing Privileged EXEC Access

use the enable secret command, not the older enable password commandenable secret provides greater security because the password is encrypted

class

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Securing User EXEC Access

Console port must be secured• reduces the chance of unauthorized personnel physically

plugging a cable into the device and gaining device access

vty lines allow access to a Cisco device via Telnet• number of vty lines supported varies with the type of

device and the IOS version

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Encrypting Password Display

service password-encryption

prevents passwords from showing up as plain text when viewing the configuration

purpose of this p pcommand is to keep unauthorized individuals from viewing passwords in the configuration file

once applied, removing the encryption service does not reverse the encryption

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Banner Messages

Important part of the legal process in the event that someone is

Switch(config)# banner motd # This is a secure system Authorized Access Only!!! #

Sw-Floor3(config)#

p p g pprosecuted for breaking into a deviceWording that implies that a login is "welcome" or "invited" is not appropriate

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Saving Configurations

Configuration FilesSwitch# show running-config

Switch# copy running-config startup-config

<Changes made>Switch# delete vlan.datDelete filename [vlan.dat]?

Delete flash:vlan.dat? [confirm]Switch# erase startup-configSwitch# reloadSystem configuration has been modified. Save? [yes/no]: nProceed with reload? [confirm]

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Capturing Text

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Capturing Text

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Ports and AddressesIP Addressing in the Large

Each end device on a network must be configured with an IP addressStructure of an IPv4address is called dotted decimalIP address displayed in p ydecimal notation, with four decimal numbers between 0 and 255With the IP address, a subnet mask is also necessaryIP addresses can be assigned to both physical ports and virtual interfacesIPv4 and IPv6 addresses will be discussed in more detail later

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Ports and Addresses

Interfaces and PortsTerms are used interchangeablySome interfaces can be can be configured with an IP address such as:

NIC (Ethernet interface) on a host/computerRouter’s Ethernet or Serial interfaces

Switches have ports (interfaces) but do not typically have IP addresses assigned to themUsed to connect devices on LANs that do have IP addresses such as hosts, routers, printers.

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Addressing Devices

Configuring a Switch Virtual Interface

Allows the network administrator to communicate (SSH, telnet, ping) with the switch.It is OPTIONALIt is OPTIONAL“Layer 2” switches do NOT need an IP address to forward Ethernet frames.IP address - together with subnet mask, uniquely identifies end device on internetwork (more later)Subnet mask - determines which part of a larger network is used by an IP address interface VLAN 1 - interface configuration mode ip address 192.168.10.2 255.255.255.0 - configures the IP address and subnet mask for the switch no shutdown - administratively enables the interfaceSwitch still needs to have physical ports configured and VTY lines to enable remote management 54

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Addressing DevicesManual IP Address Configuration for End Devices

More later!

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Addressing DevicesAutomatic IP Address Configuration for End Devices

More later!

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Addressing Devices

IP Address Conflicts

More later!

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Verifying ConnectivityTest the Loopback Address on an End Device

C:\> ping 127.0.0.1Reply from 127.0.0.1: bytes=32 time<1ms TTL=128Reply from 127.0.0.1: bytes=32 time<1ms TTL=128

Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 Reply from 127.0.0.1: bytes=32 time<1ms TTL=128 58

Verifying Connectivity

Testing the Interface Assignment

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Verifying Connectivity

Testing End-to-End Connectivity

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Configuring a Network Operating System

SummaryServices provided by the Cisco IOS accessed using a command-line interface (CLI)• accessed by either the console port, the AUX port, or through

telnet or SSH• can make configuration changes to Cisco IOS devices• a network technician must navigate through various hierarchicala network technician must navigate through various hierarchical

modes of the IOSCisco IOS routers and switches support a similar operating systemIntroduced the initial settings of a Cisco IOS switch device• setting a name• limiting access to the device configuration• configuring banner messages • saving the configuration

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Thanks to Rick Graziani for using manyof his lecture slides

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Documents

z Configuring a Network Operating z System z · Configuring a Network Operating ... Establishing a HyperTerminal session Rollover cable Console port ... • Tera Term • SecureCRT