Router emulation software2 H

This course is a practical how-to guide on installing and spinning up a GNS3 simulation with configurations for Cisco routers, Juniper routers and more.

  • Configure GNS3
    • What is GNS3?
    • Installing GNS3
    • GNS3 Initial Setup
    • Launching Your First Router
    • Virtual Switches
    • Cabling Your Equipment
    • Connecting To Your Routers
    • Capturing Traffic In GNS3
    • Documenting Your Network
    • Saving Your Configuration

What is GNS3?

9 M

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  • Episode Description
  • Transcript

1 00:00:00,,374 [NOISE] We get a lot of questions at 2 00:00:05,,119 ITProTV about how best to study for 3 00:00:11,,099 the Cisco exams. 4 00:00:14,,291 If you're working on your CCNA, CCNP, even your CCIE, those certifications, 5 00:00:19,,375 they really require hands on experience with Cisco equipment. 6 00:00:23,,240 What if you don't have that available though? 7 00:00:25,,032 Well there's a really neat product out there that can help with that and 8 00:00:29,,178 it's called GNS3. 9 00:00:30,,980 One of the nice thing about GNS3 is it is completely free. 10 00:00:32,,920 It doesn't cost you any money, so why not use it? 11 00:00:35,,532 So this series of videos that we're going to film, 12 00:00:38,,537 they're gonna show you what GNS3 is, how it works, how to use it and be able to 13 00:00:42,,760 build up a lab environment to study and practice to get ready for your exams. 14 00:00:46,,821 It's really neat stuff and it's really not that hard to get set up. 15 00:00:50,,800 Let's start off real high level though, what is GNS3? 16 00:00:54,,420 Deep down inside of it at its heart, GNS3 is really just a graphically user 17 00:00:59,,625 interface for another product called Dynamips. 18 00:01:03,,100 Dynamips is the actual heart and soul of this product. 19 00:01:07,,707 What it is, is years ago, it's a long time, a good eight to ten years ago, 20 00:01:11,,650 someone sat down and they wrote a hardware emulator for Cisco equipment. 21 00:01:16,,050 If you crack open your average Cisco router, you'll find that they have 22 00:01:20,,308 Intel processors and RAM and standard components like what you'd find in a PC. 23 00:01:25,,470 Granted it's a proprietary motherboard but 24 00:01:27,,950 the majority of the components are just standard components. 25 00:01:30,,830 So, they wrote this emulator to emulate that set of hardware so 26 00:01:34,,180 you could run the actual Cisco IOS, on this emulated platform. 27 00:01:40,,980 Well, Dynamips did a pretty good job, but it was command line only, 28 00:01:43,,850 so it wasn't very user-friendly. 29 00:01:45,,711 So the GNS3 project was started to create a graphical user interface for 30 00:01:50,,313 the Dynamips utility. 31 00:01:52,,754 And it's still Dynamips is under the hood, but 32 00:01:54,,696 the graphical user interface kind of covers all that up. 33 00:01:57,,755 And so a lot of people look at GNS3 as being a full total product, and 34 00:02:00,,310 it's actually made up of several different components. 35 00:02:04,,160 But, you don't have to worry about that. 36 00:02:06,,990 We can download and install GNS3, have it up and running, and 37 00:02:09,,670 start emulating Cisco hardware. 38 00:02:12,,890 Now, notice I'm saying emulate, not simulate. 39 00:02:15,,340 There's a lot of companies out there that do simulators, like the Boson NetiSm. 40 00:02:19,,770 And they're perfectly good products. 41 00:02:20,,458 But on those, you're not actually working with the Cisco IOS. 42 00:02:24,,620 You're usually interacting with something like a Java application. 43 00:02:27,,180 You type a command, it parses your command, and 44 00:02:30,,230 it gives you canned output that reflects what you typed. 45 00:02:33,,950 So when you type show version, it's not actually checking what IOS version you're 46 00:02:36,,000 running and displaying that. 47 00:02:38,,680 Instead it's got this canned output that it feeds you. 48 00:02:40,,470 The problem with simulators, 49 00:02:42,,860 they only support the commands that the developers put in there. 50 00:02:45,,270 So if you wanna run a command that's outside of the scope of the CCNA course, 51 00:02:49,,160 for example, it's not gonna work. 52 00:02:51,,790 Right? Now I say that's the problem. 53 00:02:52,,720 It's not really a problem. 54 00:02:53,,460 If you're studying for the exam, those simulators are great. 55 00:02:56,,420 They usually come prepackaged with labs, and they're a really valuable resource. 56 00:03:00,,849 I've used the Boson NetSim myself. 57 00:03:01,,276 I really like the product. 58 00:03:03,,589 But an emulator, with an emulator, you run the actual Cisco IOS. 59 00:03:08,,910 Every command works. 60 00:03:09,,130 Doesn't matter if it's on the exam or not, all the commands work. 61 00:03:13,,382 And it's the real IOS so it's not like you're running a command and 62 00:03:16,,533 you get canned output. 63 00:03:17,,970 You get output that's reflecting what's going on in that router at that time. 64 00:03:21,,723 So, there's the real value of an emulator. 65 00:03:24,,584 You can use GNS3 to study to get ready for the exams, you can use it to mock up 66 00:03:28,,240 networks to get ready for some kind of deployment in production. 67 00:03:32,,456 You can do all sorts of really cool things in it. 68 00:03:34,,453 It's a neat product, and 69 00:03:35,,640 the fact that it's free is really just icing on the cake. 70 00:03:37,,018 All right, if you've never heard of it before, 71 00:03:40,,824 the website is really easy to get to. 72 00:03:41,,524 It's, and so that's where I'm at right now is 73 00:03:47,,365 Their web page is fairly Spartan. 74 00:03:49,,087 Not a whole lot of stuff on here, and 75 00:03:51,,010 it really centers around getting you that software. 76 00:03:54,,223 They give a description here and they tell you it's an intuitive 77 00:03:57,,628 graphical user interface and it runs on top of multiple emulators. 78 00:04:00,,200 Dynamips is the main one. 79 00:04:02,,360 That's the Cisco IOS emulator. 80 00:04:04,,292 But it does more. 81 00:04:05,,759 You'll see there's a VirtualBox and a QEMU emulator too. 82 00:04:09,,176 Why do we need those? 83 00:04:11,,339 Well, you'll see that it adds Cisco ASA and Pix support, so if you want to 84 00:04:15,,930 do Cisco firewalls, it also allows you to do things like Juniper, Junos. 85 00:04:19,,582 If you wanna learn Juniper routers, you can bring those up. 86 00:04:22,,029 But they run on different types of hardware than what Cisco routers do, so 87 00:04:26,,590 they don't use Dynamips. 88 00:04:27,,470 They use VirtualBox and QEMU to emulate the hardware needed for them. 89 00:04:31,,248 It's a little bit different. 90 00:04:32,,940 Now you can do it all at once though. 91 00:04:33,,493 So you could have Cisco IOS routers running by the Cisco ASA, running right by 92 00:04:38,,627 a Junos router, you know you can have that flexibility, it's really, really cool. 93 00:04:43,,280 Now, one of the main questions that you'll see asked on the Internet on these various 94 00:04:48,,910 questions is. 95 00:04:49,,773 Is this legal? 96 00:04:51,,830 Well, you know, as like many of these things there's kind of a grey area here. 97 00:04:56,,686 The true honest answer at the end of the day is that yes, it is legal. 98 00:05:00,,800 The emulator itself is legal, the software is legal. 99 00:05:03,,292 Where we start to get into a problem is with the IOS, right. 100 00:05:07,,270 Cisco routers run the Internetwork Operating System, the IOS. 101 00:05:10,,525 And when you buy a Cisco router. 102 00:05:12,,140 You're also buying a license to run the IOS on that router hardware. 103 00:05:19,,430 That means, you've licensed the IOS but 104 00:05:21,,188 you've only licensed it to run on that hardware. 105 00:05:24,,742 You're not licensed to run it somewhere else. 106 00:05:26,,547 Cisco doesn't sell just licenses for the IOS. 107 00:05:29,,220 They only sell licenses for the IOS tied to hardware. 108 00:05:33,,160 So when we fire up something like GNS3 it's gonna need the operating system, 109 00:05:37,,390 it's gonna need the IOS. 110 00:05:38,,300 They don't give us that cuz they're not allowed to. 111 00:05:40,,980 That would be illegal. 112 00:05:41,,660 But if you have a copy of the IOS from your own production routers, 113 00:05:45,,770 you can throw it on here and it'll run just fine. 114 00:05:48,,930 But technically you're violating your license, 115 00:05:50,,551 cuz your license said you were licensed to run that software. 116 00:05:53,,032 On top of the Cisco hardware, not on top of GNS3 or Dynamips or whatever, 117 00:05:58,,270 all right. 118 00:05:59,,039 So is it legal? 119 00:06:01,,419 Well the software is. 120 00:06:03,,838 Using it though requires you to pull a Cisco license the wrong way which is 121 00:06:06,,420 technically not legal, right. 122 00:06:08,,979 You're violating the terms of service from Cisco. 123 00:06:10,,160 That being said, even Cisco uses GNS3 internally. 124 00:06:15,,846 So it's a very common, popular program. 125 00:06:17,,298 There's a lot of companies out there that do Cisco training and they use GNS3. 126 00:06:22,,001 So, it's something that's definitely known by Cisco and 127 00:06:25,,120 they've chosen not to enforce that license. 128 00:06:27,,349 Now, one day they may change their mind, but as of right now, 129 00:06:30,,417 they haven't enforced that license. 130 00:06:32,,842 And so many, many people, including myself make use of the product. 131 00:06:35,,315 So it is a really neat one. 132 00:06:38,,492 Well if you want to see just kind of a quick guided tour of it before we get it 133 00:06:42,,970 installed, they've got some nice screenshots here on the website. 134 00:06:46,,747 And what it does is it gives you this graphical user interface, 135 00:06:50,,042 this guy right here. 136 00:06:52,,854 The way it works is basically you have all of these routers, firewalls, Juniper 137 00:06:55,,540 routers, all of these things over her on the left; this is your network equipment. 138 00:07:00,,570 You just drag and drop it out here and you link it together. 139 00:07:04,,350 You can link it together with ethernet cables or serial cables, 140 00:07:08,,780 that's what these red lightning bolts are here. 141 00:07:09,,965 These are serial cables. 142 00:07:10,,830 They're doing simulated T1 lines or ISDN, or something like that. 143 00:07:15,,830 You can emulate technology that would be incredibly expensive to set up in your own 144 00:07:19,,570 lab, and you can bring out as many routers as you want. 145 00:07:23,,435 So instead of having to go to eBay and buy a bunch of physical used routers that may 146 00:07:27,,339 or may not work right, here, you just bring them right up. 147 00:07:30,,516 And you'll see the routers that they support, the 1700s, those are pretty 148 00:07:34,,600 low-end, pretty old routers, but they go up all the way to the 7200s. 149 00:07:38,,438 And the Cisco 7200, that's a beefy router that can perform every 150 00:07:43,,298 single activity from the CCNA, CCNP, and CCIE exams. 151 00:07:47,,435 It's a really, really powerful router framework, so 152 00:07:50,,020 you really get that full feature set. 153 00:07:53,,008 And they don't show it here in this screen shot, 154 00:07:55,,668 let me see if they have one that shows it. 155 00:07:56,,640 When you add a router in, you can pull up the properties of that router and 156 00:08:00,,660 start to manipulate its settings. 157 00:08:02,,473 And, yeah they don't really show it here. 158 00:08:04,,571 But you can manipulate the settings as far as inserting different WICs, 159 00:08:07,,700 the WAN interface cards. 160 00:08:08,,102 You can choose which cards you want in it, 161 00:08:11,,409 to make that router unique for that particular purpose. 162 00:08:14,,790 You know like these routers here. 163 00:08:16,,758 Cisco routers don't typically come with serial ports by default. 164 00:08:19,,019 So somebody's added cards into these routers to be able to have that 165 00:08:23,,450 connectivity. 166 00:08:24,,446 You get link lights and 167 00:08:25,,395 information as far as whether the connections are up and working. 168 00:08:28,,530 And you can start and stop the routers. 169 00:08:30,,363 You can back up their configurations and build some really cool labs. 170 00:08:34,,880 They even have some labs available for download on their site. 171 00:08:36,,010 If you look up here, we've got this labs tab and 172 00:08:39,,336 you'll see here some, it looks like they just have the Juniper ones now. 173 00:08:42,,760 But they're working on Cisco ones. 174 00:08:43,,028 I know those are coming out soon. 175 00:08:46,,960 But, actually that's what they're saying right here. 176 00:08:48,,245 Labs will come very soon for Cisco. 177 00:08:51,,750 But basically it's a very valuable resource, and 178 00:08:53,,370 it's a great alternative to going out and buying the physical hardware. 179 00:08:57,,292 Now, can you buy the physical hardware? 180 00:08:59,,906 Absolutely. 181 00:08:59,,277 That's what I did when I got started. 182 00:09:01,,840 I went out and ordered eight routers. 183 00:09:02,,755 It cost me a ton of money, and they were super loud and 184 00:09:05,,021 ate up a lot of electricity at the house. 185 00:09:08,,130 But that's how I learned, over ten years ago. 186 00:09:10,,660 Right. 187 00:09:10,,093 Because we didn't have things like this. 188 00:09:12,,400 If I had to do it again today, I never would've bought all that equipment, right. 189 00:09:15,,443 It was a lot of money kinda down the drain. 190 00:09:17,,293 Versus this, where I could whip up whatever environment I wanted and when I 191 00:09:21,,344 was done I could just shut it down and it's not consuming extra power and so on. 192 00:09:25,,204 The other thing is it's really efficient, we'll see this a little bit later, how it 193 00:09:29,,890 manages CPU and how it manages memory, it does a really good job on those things. 194 00:09:32,,449 So GS3, very powerful software package, does a lot of great things. 195 00:09:38,,925 Wonderful for your studies. 196 00:09:39,,452 All right, that's enough of an introduction for GNS3. 197 00:09:43,,746 Now we're going to move into our next set of videos, where we'll start to show how 198 00:09:46,,916 to get it installed and how to actually make use of it. 199 00:09:48,,354 So, stay tuned. 200 00:09:50,,375 We'll be back with more. 201 00:09:52,,049 [MUSIC]

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