back

GNS3

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.

Episodes
Episodes
  • 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

itprotv course thumbnailitprotv course thumbnailitprotv course thumbnail
  • 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 GNS3.net, and so that's where I'm at right now is GNS3.net. 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]

Just you? Training a whole team? There's an ITProTV plan that fits.

With more than 4,000 hours of engaging video training for IT professionals, you'll find the courses you and your team need to stay current and get the latest certifications.