How to Master CCNAAll contents copyright C 2002-2013 by René Molenaar. All rights reserved. No part of thisdocument or the related files may be reproduced or transmitted in any form, by any means(electronic, photocopying, recording, or otherwise) without the prior written permission ofthe publisher.Limit of Liability and Disclaimer of Warranty: The publisher has used its best efforts inpreparing this book, and the information provided herein is provided "as is." René Molenaar.makes no representation or warranties with respect to the accuracy or completeness of thecontents of this book and specifically disclaims any implied warranties of merchantability orfitness for any particular purpose and shall in no event be liable for any loss of profit or anyother commercial damage, including but not limited to special, incidental, consequential, orother damages.Trademarks: This book identifies product names and services known to be trademarks,registered trademarks, or service marks of their respective holders. They are usedthroughout this book in an editorial fashion only. In addition, terms suspected of beingtrademarks, registered trademarks, or service marks have been appropriately capitalized,although René Molenaar cannot attest to the accuracy of this information. Use of a term inthis book should not be regarded as affecting the validity of any trademark, registeredtrademark, or service mark. René Molenaar is not associated with any product or vendormentioned in this – René MolenaarPage 2 of 466

How to Master CCNAIntroductionOne of the things I do in life is work as a Cisco Certified System Instructor (CCSI) and afterteaching CCNA for a few years I‟ve learned which topics people find difficult to understand.This is the reason I created where I offer free Cisco labs and videos tohelp people learn networking. The problem with networking is that you need to know whatyou are doing before you can configure anything. Even if you have all the commands youstill need to understand what and why you are typing these commands. I created this bookto give you a compact guide which will provide you the answer to what and why to help youmaster the CCNA exam.I have tried to put all the important keywords in bold. If you see a term or concept inbold it‟s something you should remember / write down and make sure you understand itsince its core knowledge for your CCNA!One last thing before we get started. When I‟m teaching I always advise students to createmindmaps instead of notes. Notes are just lists with random information while mindmapsshow the relationship between the different items. If you are reading this book on yourcomputer I highly suggest you download “Xmind” which you can get for free here:http://xmind.netIf you are new to mindmapping, check out “Appendix A – How to create mindmaps” at theend of this book where I show you how I do it.I also highly recommend you to follow me along when I‟m demonstrating the configurationexamples. Boot up GNS3 and/or your switches and configure the examples I‟m showing youby yourself. You‟ll learn more by actively working on the equipment compared to justpassive reading.Enjoy reading my book and good luck getting your CCNA certification!P.S. If you have any questions or comments about this book, please let me com – René MolenaarPage 3 of 466

How to Master CCNAIndexIntroduction . 31. Lab Equipment . 52. Basics of networking . 103. The OSI-Model . 164. The network layer: IP Protocol . 245. The Transport Layer: TCP and UDP . 406. Ethernet: Dominating your LAN for over 30 years . 487. Introduction to Cisco IOS . 588. Hubs, Bridges and Switches . 879. Virtual LANs (VLANs), Trunks and VTP . 10210. Etherchannel (Link Aggregation) . 14311. Spanning-Tree (STP) . 15212. Binary, Subnetting and Summarization. . 18313. IP Routing . 20814. FHRP (First Hop Redundancy Protocols) . 22915. Distance Vector Routing Protocols . 24916. OSPF – Link-state routing protocol . 26417. EIGRP – Cisco‟s Hybrid Routing Protocol . 29418. Security: Keeping the bad guys out. . 31219. Network and Port address Translation (NAT & PAT) . 33020. Wide area networks . 34221. Introduction to IPv6 . 37922. IPv6 NPD and Host Configuration . 40023. IPv6 Routing . 40924. Virtual Private Networks . 42525. Network Management . 43326. IOS Licensing . 45727. Final Thoughts. 464Appendix A – How to create mindmaps . – René MolenaarPage 4 of 466

How to Master CCNA1. Lab Equipment“If I had eight hours to chop down a tree, I'd spend six hours sharpening my ax” Abraham LincolnBefore we are going to start on our networking journey we will take a look at thenetworking equipment that you will need. If you want to master the CCNA exam you‟ll haveto do two things: Read this book so you learn about all the different protocols and understand thetheory.Implement your knowledge by configuring these protocols on our routers andswitches.So what equipment should you get?For most of the labs you can use GNS3. This is an emulator that runs the Cisco IOSsoftware but you can only emulate routers no switches. You can download GNS3 forfree from but you‟ll have to supply the IOS image yourself. Cisco owns thecopyright on IOS so it can‟t be shared freely. I suggest using the 3640 or 3725 router inGNS3.Courtesy of Cisco Systems, Inc. Unauthorized use not permitted.The closest you can get to emulate a switch in GNS3 is inserting this NM16-ESW Etherswitchmodule in your virtual router.It adds 16 switch ports to your virtual router and supports basic switching features.Unfortunately this module is very limited and I don‟t recommend using it for CCNA.GNS3 isn‟t very difficult to work with but there is one thing you need to be aware of. Mostpeople complain that whenever they start an emulated router that they see their CPU jumpto 100%. You can fix this by setting a correct IDLEPC value. If you are configuring GNS3you need to check this video where I explain you how to do it: – René MolenaarPage 5 of 466

How to Master CCNASo what do we need? My advice is to use GNS3 for all your routing labs and buy somereal physical switches for the switching labs. Don‟t be scared I‟m not going to adviseyou to buy ultra-high tech brand new switches! We are going to buy used Cisco switchesthat are easy to find and they won‟t burn a hole in your wallet Without further ado here are our candidates:Courtesy of Cisco Systems, Inc. Unauthorized use not permitted.Cisco Catalyst 2950: This is a layer 2 switch that does everything you need for CCNA.If you look at eBay you can find the Cisco Catalyst 2950 for around 30. It doesn‟t matter ifyou buy the 8, 24 or 48 port model. Not too bad right? Keep in mind you can sell them onceyou are done with CCNA without losing (much) money. This switch is cheap and perfect forCCNA! Once you have your switches you should connect them like a0/FaFa00/FaFaFa0/Fa0 13/142950SwitchAFa0/16Fa0/172950SwitchCIf you plan to study CCNP after completing CCNA I can highly recommend swapping oneCisco Catalyst 2950 for a Cisco Catalyst – René MolenaarPage 6 of 466

How to Master CCNACourtesy of Cisco Systems, Inc. Unauthorized use not permitted.Cisco Catalyst 3550: It offers pretty much the same features as the 2950 but it alsosupports routing which we require for CCNP.What about other switch models? Anything else we can use for CCNA? The Cisco Catalyst 2960 is the successor of the Cisco Catalyst 2950, it‟s a great layer2 switch but more expensive.The Cisco Catalyst 3560 is the successor of the Cisco Catalyst 3550, it also offersrouting features but it‟s quite more expensive around 300 on eBay.The Cisco Catalyst 3750 is also a switch that can do routing but it‟s very expensive.My advice is to get the 3x Cisco Catalyst 2950 or 2x Cisco Catalyst 2950 and 1x CiscoCatalyst 3550 if you want to study CCNP after your CCNA.Are there any switches that you should NOT buy? Don‟t buy the Cisco Catalyst 2900XL switch; you‟ll need at least the Cisco Catalyst2950 switch. Many features are not supported on the Cisco Catalyst 2900XL switch.Don‟t buy the Cisco Catalyst 3500XL switch, same problem as the one above.You also have to buy some – René MolenaarPage 7 of 466

How to Master CCNAAbove you see the blue Cisco console cable. It probably comes with the switch but makesure you have at least one. You‟ll need this to configure your switches.If your computer doesn‟t have any serial ports to connect your blue Cisco console cable youneed to get one of these. It‟s a USB to serial port converter.Courtesy of König Electronic Inc. Unauthorized use not permitted.I also like to use one of these. It‟s a USB connector with 4x RS-232 serial connectors youcan use for your blue Cisco console cables to connect to your switches.It saves the hassle of plugging and unplugging your console cable between your switches.The one I‟m using is from KÖNIG and costs around 30. Google for “USB 4x RS-232” andyou should be able to find something similar.Between the switches you‟ll require UTP cables. There‟sa difference between straight through and crossovercables (we‟ll talk about that later in the book). Modernswitches and network cards support auto-sensing so itreally doesn‟t matter what kind of cable you use.If you are going to connect your 2950 switches to eachother make sure you buy crossover cables since theydon‟t support auto-sensing! – René MolenaarPage 8 of 466

How to Master CCNAIt will be useful if you have one old extra computer or laptop that you can use to connect toyour switches.Now you know the equipment that you need, it‟s time to dive into networking! – René MolenaarPage 9 of 466

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How to Master CCNA2. Basics of networkingBefore we start digging into complex stuff we‟ll have a little talk about networks.What is a network anyway?A network is just a collection of devices and end systems connected to each other and ableto communicate with each other. These could be computers, servers, smartphones, routersetc. A network could be as large as the internet or as small as your two computers at homesharing files and a printer.Some of the components that make up a network: Personal Computers (PC): These are the endpoint of your network, sending andreceiving data.Interconnections: These are components that make sure data can travel from onedevice to another, you need to think about:o Network Cards: they translate data from your computer in a readable formatfor the network.o Media: network cables, perhaps wireless.o Connectors: the plug you plug in your network card.Switches: These boxes are network devices which provide a network connection foryour end devices like PC‟s.Routers: Routers interconnect networks and choose the best path to each networkdestination.If you are going to work with Cisco you‟ll have to get used to some network diagrams likethe one a1S0/0RouterSo what do we see in the network diagram above? First of all we see a computer connectedto a switch. On the switch side you see “Fa0/1” which means the computer is connected tothe FastEthernet 0/1 interface on the switch side. The 0 is the controller number (usually 0on smaller switches) and the 1 is the port number. Our switch is connected to a router usingits FastEthernet 0/24 interface. Our routers are connected using FastEthernet as well. Therouter at the bottom has a connection to the Internet using a Serial – René MolenaarPage 10 of 466

How to Master CCNADon‟t worry about what a switch or router is and the difference between them; we‟ll get tothat later!So why do we use networks? I think this one is obvious since you are using networks on adaily basis but let‟s sum up what we use networks for: Applications: Sending data between computers, sharing files.Resources: Network printers, network cameras.Storage: Using a NAS (Network attached storage) will make your storage availableon the network. Many people use one at home nowadays to share files, videos andpictures between computers.Backup: Using a central backup server where all computers send their data to forbackup.VoIP: Voice over IP is becoming more important and every day and replacing analogtelephony.We are all using applications on a daily basis but if we look at them with a network-mindedview we can divide them in 3 different categories: Batch applications File transfers like FTP, TFTP, perhaps a HTTP download. Could be a backup atnight. No direct human interaction. High bandwidth is important but not critical.A batch application is something you just let run and you don‟t care if it takes a minutemore or less since nobody is “waiting” for a response. This could be a backup job overnight.It doesn‟t matter if it takes an hour or more; however, if it takes days then it‟s a problem.TFTP is like a „stripped down‟ version of FTP and is used sometimes to copy filesfrom and to a Cisco router or switch. Interactive applications Human-to-Human interaction Someone is waiting for a response, so response time (delay) is important.With interactive applications you need to think about someone who is working on adatabase server and sending commands. Once your press enter you want it to respond fastbut a second more or less is perhaps not THAT annoying. Another example is two users whoare using a chat application, you don‟t want to wait 20 seconds before you receive themessage from another user but a second more or less doesn‟t matter. Real-time applications Also Human-to-Human interaction VoIP (Voice over IP) or live Video conferencing. End-to-end delay is critical.Imagine you are talking to someone on the phone using Voice over IP and you need to wait2 seconds before you hear a reply this is VERY annoying and it‟s hard to have – René MolenaarPage 11 of 466

How to Master CCNAconversation like that. Everything above 300ms of delay (1000ms is a second) you will havea hard time having a good conversation since it‟ll be more like a “walkie-talkie”conversation. Latency is critical when using VoIP or live Video. A delay above 150ms (1/8 ofa second) is noticeable.When we look at networks we have different types of “Topologies” and we have twodifferent topologies: Physical topologyLogical topologyThere‟s an important difference between the two. The physical topology is what the networklooks like and how all the cables and devices are connected to each other. The logicaltopology is the path our data signals take through the physical topology.There are multiple types of physical topologies: Bus topology: One of the first networks was based on coax-cables. This wasbasically just one long cable and every device was connected to it. At the end of thecable you had to place a terminator. If the cable breaks then your network is down. Ring topology: All computers and network devices are connected on a cable andthe last two devices are connected to each other to form a “ring”. If the cable breaksyour network is down. There‟s also a “dual-ring” setup for redundancy, this is justanother cable to make sure if one cable breaks your network isn‟t going – René MolenaarPage 12 of 466

How to Master CCNA Star topology: All our end devices (computers) are connected to a central devicecreating a star model. This is what we use nowadays on local area networks (LAN)with a switch in the middle. The physical connections we normally use is UTP(Unshielded twisted pair) cable. Of course when your switch goes down your networkis down as – René MolenaarPage 13 of 466

How to Master CCNAThe example above is what we normally use on our local area networks (LAN). Now let‟stake a look at the following picture where we have a company with multiple sites in differentcities.BostonNewYorkAmsterdamParisIn the example above every router is connected to every other router. This, of course, isvery resistant to failure since a single link failure will not bring our network down. Thedownside of this setup is that it‟s very expensive. You need multiple links between the sitesand each router needs extra interfaces. This is what we call full-mesh.Another option is to make sure the important sites have connections to all other sites like inthe following – René MolenaarPage 14 of 466

How to Master CCNAHere you can see router New York has a connection to all other routers, Boston is onlyconnected to New York and Amsterdam has a connection to New York and Paris. This is atrade-off between fault tolerance and cost (it‟s always about money right?). We call thispartial-Mesh.In the next chapter we‟ll dive deeper into the basics of – René MolenaarPage 15 of 466

How to Master CCNA3. The OSI-ModelIn the beginning the development of networks was chaotic. Each vendor had its ownproprietary solution. The bad part was that one vendor‟s solution was not compatible withanother vendor‟s solution. This is where the idea for the OSI-model was born, having alayered approach to networks our hardware vendors would design hardware for thenetwork, and others could develop software for the application layer. Using an open modelwhich everyone agrees on means we can build networks that are compatible with eachother.To fix this problem the International Organization for Standardization (ISO) researcheddifferent network models and the result is the OSI-model which was released in 1984.Nowadays most vendors build networks based on the OSI model and hardware fromdifferent vendors is compatible .excellent!The OSI-model isn‟t just a model to make networks compatible; it‟s also one of the BESTways to teach people about networks. Keep this in mind since I‟ll be referring a lot to theOSI-model, it‟s very useful!Layer 7ApplicationLayer 6PresentationLayer 5SessionLayer 4TransportLayer 3NetworkLayer 2Data LinkLayer 1Physical“All People Seem To Need Data Processing”This is the OSI-model which has seven layers; we are working our way from the bottom tothe – René MolenaarPage 16 of 466

How to Master CCNALet‟s start at the physical layer: Physical Layer: This layer describes stuff like voltage levels, timing, physical datarates, physical connectors and so on. Everything you can “touch” since it‟s physical. Data Link: This layer makes sure data is formatted the correct way, takes care oferror detection and makes sure data is delivered reliably. This might sound a bitvague now, for now try to remember this is where “Ethernet” lives. MAC Addressesand Ethernet frames are on the Data Link layer. Network: This layer takes care of connectivity and path selection (routing). This iswhere IPv4 and IPv6 live. Every network device needs a unique address on thenetwork. Transport: The transport layer takes care of transport, when you downloaded thisbook from the Internet the file was sent in segments and transported to yourcomputer.o TCP lives here; it‟s a protocol which send data in a reliable way.o UDP lives here; it‟s a protocol which sends data in an unreliable way.I‟m taking a short break here, these four layers that I just described are important fornetworking, and the upper three layers are about applications. Session: The session layer takes care of establishing, managing and termination ofsessions between two hosts. When you are browsing a website on the internet youare probably not the only user of the webserver hosting that website. This webserverneeds to keep track of all the different “sessions”.Presentation: This one will make sure that information is readable for theapplication layer by formatting and structuring the data. Most computers use theASCII table for characters. If another computer would use another character likeEBCDIC than the presentation layer needs to “reformat” the data so both computersagree on the same characters.Application: Here are your applications. E-mail, browsing the web (HTTP), FTP andmany more.“People Do Need To See Pamela Anderson”This one normally gives me more smiles when I‟m teaching CCNA in class and it‟s anotherway to remember the OSI-Model.P PhysicalD Data LinkN NetworkT TransportS SessionP PresentationA – René MolenaarPage 17 of 466

How to Master CCNARemember that you can‟t skip any layers in the OSI-model, it‟s impossible to jump from theApplication layer directly to the Network layer. You always need to go through all the layersto send data over the network.Let‟s take a look at a real life example of data transmission.1. You are sitting behind your computer and want to download some files of a localwebserver. You start up your web browser and type in the URL of your favoritewebsite. Your computer will send a message to the web server requesting a certainweb page. You are now using the HTTP protocol which lives on the application layer.2. The presentation layer will structure the information of the application in a certainformat.3. The session layer will make sure to separate all the different sessions.4. Depending on the application you want a reliable (TCP) or unreliable (UDP) protocolto transfer data towards the web server, in this case it‟ll choose TCP since you wantto make sure the webpage makes it to your computer. We‟ll discuss TCP and UDPlater.5. Your computer has a unique IP address (for example and it will buildan IP packet. This IP packet will contain all the data of the application, presentationand session layer. It also specifies which transport protocol it‟s using (TCP in thiscase) and the source IP address (your computer and the destination(the web server‟s IP address).6. The IP packet will be put into an Ethernet Frame. The Ethernet frame has a sourceMAC address (your computer) and the destination MAC address (web server). Moreabout Ethernet and MAC addresses later.7. Finally everything is converted into bits and sent down the cable using electricsignals.Once again, you are unable to “skip” any layers of the OSI model. You always have to workyour way through ALL layers. If you want a real life story converted to networking land justthink about the postal service: you write a letter.You put the letter in an envelope.You write your name and the name of the receiver on the envelope.You put the envelope in the mailbox.The content of the mailbox will go to the central processing office of the postalservice.6. Your envelope will be delivered to the receiver.7. They open the envelope and read its contents.If you put your letter directly in the mailbox it won‟t be delivered. Unless someone at thepostal office is friendly enough to deliver it anyway, in network-land it doesn‟t work thisway!Going from the application layer all the way down to the physical layer is what we callencapsulation. Going from the physical layer and working your way up to the applicationlayer is called – René MolenaarPage 18 of 466

How to Master CCNANow you know about the OSI-model, the different layers and the function of each layer.During peer-to-peer communication each layer has „packets of information‟. We call theseprotocol data units (PDU). Now every unit has a different name on the different layers: Transport layer: Segments; For example we talk about TCP segments.Network layer: Packets; For example we talk about IP packets here.Data link layer: Frames; For example we talk about Ethernet frames here.This is just terminology but don‟t mix up talking about IP frames and Ethernet packets Excellent so now you know everything you need about the OSI-model and the differentlayers. We‟ll be looking at the different layers throughout this book so you‟ll get some more“practice” remembering them.Besides the OSI-model there was another organization that created a similar model whichnever became quite as popular. However for your CCNA you‟ll need to know what it lookslike. It‟s called the TCP/IP stack and it‟s similar except some of the layers are combined andhave different names.TCP/IP StackApplicationTransportInternetNetwork AccessAs you can see the upper three layers are now combined to the “Application layer”. Thenetwork layer is called the “Internet” layer and the bottom 2 layers are combined into the“Network Access” – René MolenaarPage 19 of 466

How to Master CCNAHere‟s a comparison between the two models:OSI ModelTCP/IP sportTransportNetworkInternetData LinkNetwork AccessPhysicalBasically it‟s the same idea, same model except with some layers combined and differentnames. The physical and data link layer are combined into the network access layer. Thenetwork layer is now the internet layer and the session, presentation and application layerare combined into a single application layer.I want to show you an example of what this looks like on a “live” network and the best wayto do this is by using wireshark. Wireshark is a protocol sniffer which will show you all thedata that is being sent and received on your network card.You can download wireshark (it‟s free) from – René MolenaarPage 20 of 466

How to Master CCNAThe example in the picture above is a capture of a computer requesting a webpage from awebserver. I didn‟t capture this one myself since the Wireshark website has a lot of goodexample captures. If you want to look at this capture on your own computer you candownload it on AttachFile&do view&target http gzip.capYou can see there are ten IP packets here, with the source IP address and the destination IPaddress. It also shows you which protocol this IP packet is – René MolenaarPage 21 of 466

How to Master CCNAHere you see one of the Ethernet frames. Do you see the different layers of the OSI-model? Frame 1 / Ethernet II: This is the Data Link layer.Internet Protocol: This is the Network layer.Transmission Control Protocol: This is the Transport layer.If we click on the arrows we can see its contents.I just clicked on the arrows and you can see the contents of the Ethernet Frame. Don‟tworry if you have no idea what you see here we‟ll talk about it later. What I want to showyou here is the last line, it says “Type: IP (0x0800)”.What it means is that this computer is carrying an IP packet. Let‟s see if we can see thecontents of this IP – René MolenaarPage 22 of 466

How to Master CCNAInteresting we can see the source IP and destination IP address. If you look closely you seethere‟s a line which says “Protocol: TCP (6)”. This is how the IP packet specifies whichtransport protocol it is carrying, in this case TCP.Let‟s take a look at that TCP segment:Don‟t let all this information get to you, I only want to show you the field that says“Destination port: http (80)”. This is how the transport layer tells us for which applicationthis information is meant, we are using port numbers to do so. In this case port 80 for HTTPtraffic.Pretty neat huh? If you feel like it play around a bit with wireshark and look at some of thepackets. If you want to see some pre-capt

Jan 25, 2013 · How to Master CCNA – René Molenaar Page 6 of 466 So what do we need? My advice is to use GNS3 for all your routing labs and buy some real physical switches for the switching labs. Don‟t be scared I‟m not going to advise you to buy ultra-high tech brand new switches! We are going to buy used Cisco switchesFile Size: 3MBPage Count: 106