CISCO PACKET TRACER LABS E-Book

Mulayam Singh

• Herausgeber: BookRix
• Kategorie: Fachliteratur
• Sprache: Englisch

Veröffentlichungsjahr: 2019

Beschreibung

Do you want to find out how a computer network works? Do you want to know how to keep your network safe?  This book is all you need!

In this book, you will get to know about resolving hostnames, resetting cisco router and switch password, CDP and LLDP, Telnet and SSH, Netflow collector and many other interesting networking topics are well described in this book. Please go through it, hope you will find it informative. All the chapters in this book written based on the author knowledge itself who is working in the network field for a long time. He has a good command of networking over few years. Chapters are based on practical based which will help readers to understand networking easily. Please send an email to [email protected] for any query related. You will get a response instantly.

Leseprobe

Mulayam Singh

CISCO PACKET TRACER LABS

Best practice of configuring or troubleshooting Network

There are many people who work to put a book together, and as an author, I dedicated an enormous amount of time to write this book, but it would have never been published without the dedicated, hard work of many other people. BookRix GmbH & Co. KG81371 Munich

Table of Content

1. Making a list of Network Topology using CDP.

CDPCDP holdtimeCDP neighbors details

2. How to set a Network Monitoring tool or Netflow collector

NetFlow collectorIngress and egress portsSteps to avoid an error

3.How to use Telnet

VTY passwordTelnet connectionsConnected usersClosing sessions

4.Link Layer Discovery Protocol (LLDP)

LLDP

5.Exploring Connected Devices Using CDP and LLDP

LLDP holdtimeLLDP neighbors details

6. How to reset Cisco Password

Rommon modeConfreg 0x2142enabling new passwordSteps to avoid errors

7.How to resolve hostnames

Building a host table in a routertelnet login failed with hostnameSteps to avoid  login errors

Network With Practical Version 2

Making a list of Network Topology using CDP.

CDP stands for Cisco Discovery Protocol. It is a Cisco proprietary Layer 2 protocol to help administrators collect information about locally attached Cisco devices. Armed with CDP, we can gather hardware and protocol information about directly connected devices, which is crucial information to have when troubleshooting and documenting the network. Another dynamic discovery protocol is the Link Layer Discovery Protocol (LLDP), it is not a proprietary of any vender.

Let’s start by exploring the CDP timer and CDP commands we’ll need to verify our network.

If you run show CDP command on router or switch. It will give you two CDP global parameters that can be configured on Cisco devices. Cisco switch and router both use the same parameters.

1. CDP timer delimits how often CDP packets are transmitted out all active interfaces.

2. CDP hold time delimits the amount of time that the device will hold packets received from neighbor devices.

As I created a small topology that is given below in the picture. I use sho CDP command on Lucknow Router (in the pic). Cisco device sends a packet every 60 seconds to its neighbor devices and receives the same from them. It also shows the hold time value that is 180 seconds. Third line sending CDPv2 advertisements is enabled which means CDP neighbors are enabled in these devices.

We can use the global commands CDP hold time and CDP timer to configure the CDP hold time and timer on a router if necessary like this.

Lucknow(config)#cdp ?

advertise-v2 CDP sends version-2 advertisements

hold time Specify the hold time (in a sec) to be sent in packets

run Enable CDP

timer Specify the rate at which CDP packets are sent (in a sec)

tlv Enable exchange of specific tlv information

Lucknow(config)#cdp holdtime ?

Length of time (in sec) that receiver must keep this packet

Lucknow(config)#cdp timer?

Rate at which CDP packets are sent (in sec)

It is very simple to turn off and turn on CDP on the device.

Router(config)#no cdp run

Router(config)#cdp run

To enable or disable cdp on interface.

Router(config-interface)#no cdp enable

Router(config-interface)#cdp enable

When you talk about real-life scenarios, CDP is a very important protocol to know about directly connected Cisco devices. We will learn how to determine the appropriate type of interfaces, types of routers, types of switches and types of many more cisco devices. It is very simple to check all types of information in router or switch configuration. It is show run-configuration. Below is a sample topology to understand in a better way.

If you run show run-configuration command on Lucknow Router. It will show you all configurations of connected interfaces and their IP addresses.

Lucknow#sho running-configuration

Building configuration...

Current configuration : 1893 bytes

!

version 15.1

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

hostname Lucknow

enable secret 5 $1$mERr$S2J0PLD663PUV5eUWariu0

ip cef

no ipv6 cef

username abcd

license udi pid CISCO2911/K9 sn FTX15242DCK

interface Loopback1

bandwidth 10000

ip address 192.168.10.5 255.255.255.0

interface GigabitEthernet0/0

ip address 192.168.2.1 255.255.255.0

duplex auto

speed auto

interface GigabitEthernet0/1