1 00:00:05,160 --> 00:00:12,300 Now you will learn a lot more by doing rather than just watching me talk about protocols and talk about 2 00:00:12,300 --> 00:00:13,110 things. 3 00:00:13,140 --> 00:00:17,370 So make sure that you download this packet tracer file and try this yourself. 4 00:00:17,370 --> 00:00:24,000 I'm going to walk you through a scenario and a few scenarios in this video and in subsequent videos 5 00:00:24,480 --> 00:00:25,140 and labs. 6 00:00:25,140 --> 00:00:31,920 But try this yourself you will learn far more by doing than by watching or listening. 7 00:00:32,280 --> 00:00:35,000 You learn to ride a bicycle by riding. 8 00:00:35,010 --> 00:00:40,170 You don't learn to ride a bicycle by watching someone else ride a bicycle or watching videos. 9 00:00:40,560 --> 00:00:42,660 So try this yourself. 10 00:00:42,780 --> 00:00:42,990 Okay. 11 00:00:42,990 --> 00:00:49,740 So in this example I've got a topology consisting of multiple devices so zooming out I've got a whole 12 00:00:49,740 --> 00:00:50,810 bunch of devices. 13 00:00:50,820 --> 00:00:59,640 But for this initial video we're going to concentrate on this P.C. which is in our internal network. 14 00:00:59,700 --> 00:01:03,360 In other words think of this as being at your home or company. 15 00:01:03,360 --> 00:01:06,510 And then we've got a device that's connected to the Internet here. 16 00:01:06,870 --> 00:01:09,450 So this would be our Internet reporter. 17 00:01:09,720 --> 00:01:15,260 What we're going to do however is connect to a server in our internal network. 18 00:01:15,490 --> 00:01:19,030 Now at home you may have multiple Internet connected devices. 19 00:01:19,080 --> 00:01:25,980 You could as an example simply open up a web browser on your P.C. and connect it to your Internet router. 20 00:01:25,980 --> 00:01:33,360 As an example if I open up a web browser and connect to an IP address in my network and don't worry 21 00:01:33,360 --> 00:01:36,470 too much about IP addresses at this point if you don't understand them. 22 00:01:36,690 --> 00:01:43,110 Basically an IP address is a number that you allocate to a device that allows it to communicate using 23 00:01:43,110 --> 00:01:50,220 a protocol which in this example is IP IP version 4 in this specific example here. 24 00:01:50,340 --> 00:01:57,810 I've got a Beatty home hub when you connect to Web sites such as Facebook dot com that is going to be 25 00:01:57,810 --> 00:02:06,020 using a protocol in this example HDP X which is an encrypted version of a GDP. 26 00:02:06,130 --> 00:02:07,970 A different protocol but that's kind of what it is. 27 00:02:07,980 --> 00:02:13,940 We encrypting HDP so you may have devices at home that you can connect to. 28 00:02:14,010 --> 00:02:18,180 We going to mimic that or represent that in Packet Tracer. 29 00:02:18,180 --> 00:02:21,510 So on the left here I have some servers running internally. 30 00:02:21,570 --> 00:02:27,680 I have a Internet router which is connecting me to the Internet as a further demonstration. 31 00:02:27,720 --> 00:02:28,770 I've got an iPhone. 32 00:02:28,950 --> 00:02:30,690 I could connect to that light. 33 00:02:30,690 --> 00:02:37,350 That's a cue like using Bluetooth and then do something to that light in your home you may have some 34 00:02:37,350 --> 00:02:44,690 devices that are connected via IP as well that light isn't using IP as in normal IP using Bluetooth. 35 00:02:44,730 --> 00:02:51,210 I'm connecting to that light via Bluetooth from my iPhone and turning it on and off but this light as 36 00:02:51,210 --> 00:02:59,280 an example is connected via IP so I can go on to my phone and then I could say OK let's turn that light 37 00:02:59,310 --> 00:02:59,940 off. 38 00:02:59,940 --> 00:03:01,040 So it's gone off. 39 00:03:01,140 --> 00:03:09,790 Turn it on now the way that works is I'm simply connecting to that light via TTP IP. 40 00:03:09,990 --> 00:03:14,190 You can actually look at the traffic on your home network using an application called wire shock. 41 00:03:14,190 --> 00:03:19,770 I'll talk about that in a separate video but in this example let's use Packet Tracer so that we can 42 00:03:19,770 --> 00:03:22,620 talk about the same protocols together. 43 00:03:23,340 --> 00:03:34,430 So on this P.C. I'm an open up a desktop and I'm going to open up a web browser now before I connect 44 00:03:34,670 --> 00:03:41,510 to a server I'm going to change the packet tracer mode to simulation mode so that we can see the actual 45 00:03:41,510 --> 00:03:44,390 packets going across the network. 46 00:03:44,390 --> 00:03:47,490 Now I need you to know some terms for the CCMA exam. 47 00:03:47,510 --> 00:03:51,650 It's basically how we referred to stuff if you like at the different layers. 48 00:03:51,920 --> 00:03:59,390 So when data is sent at the physical layer we sending zeros and ones across the physical layer that's 49 00:03:59,390 --> 00:04:00,680 known as butts. 50 00:04:00,680 --> 00:04:05,500 So the bits of data are represented on a fibre cable as light. 51 00:04:05,600 --> 00:04:09,590 So as a basic analogy if there's light it means a one. 52 00:04:09,590 --> 00:04:12,030 If there's no light it means a zero. 53 00:04:12,050 --> 00:04:14,480 So zero one would represent. 54 00:04:14,500 --> 00:04:19,820 That's why binary values on copper. 55 00:04:19,820 --> 00:04:21,290 Do we have electricity or not. 56 00:04:21,290 --> 00:04:28,730 So most fundamental example would be if there is electricity on a wire it means one if there is no electricity. 57 00:04:28,730 --> 00:04:30,020 It means a zero. 58 00:04:30,020 --> 00:04:34,010 So think of this as a light going on and a light going off is it on. 59 00:04:34,010 --> 00:04:34,530 Is it off. 60 00:04:34,540 --> 00:04:36,000 And that represents of. 61 00:04:36,030 --> 00:04:40,890 That's so it layer one we have bits on top of that we have frames. 62 00:04:40,910 --> 00:04:43,820 So at layer two we talk about a frame. 63 00:04:43,820 --> 00:04:50,670 So when we sending data through an Ethan it switch which is a so-called layer two device we are sending 64 00:04:50,670 --> 00:04:51,250 frames. 65 00:04:51,270 --> 00:04:53,170 So I'll use these terms. 66 00:04:53,280 --> 00:04:56,880 Frame is getting switched from one port on a switch to another. 67 00:04:56,880 --> 00:05:04,200 So when you hear the term frame remember layer two at least three we have what are called packets so 68 00:05:04,470 --> 00:05:10,560 a router which is a layer 3 device will rot packets from one interface to another and add layer four 69 00:05:10,560 --> 00:05:12,100 we have segments. 70 00:05:12,240 --> 00:05:19,830 So layer 1 is bits Layer two is frames Layer three is packets layer four segments and then at layer 71 00:05:19,830 --> 00:05:22,540 five to seven we have an application. 72 00:05:22,540 --> 00:05:27,510 Now let me warn you as I demonstrate these protocols it's going to take time because there's a lot of 73 00:05:27,510 --> 00:05:33,990 information you may find that it gets a bit boring if you do then do this yourself have a look at the 74 00:05:33,990 --> 00:05:39,270 protocols yourself and try and understand the messages but I'm going to spend quite a bit of time going 75 00:05:39,270 --> 00:05:46,110 through layer to layers really of four and the layer seven applications to try and help you understand 76 00:05:46,110 --> 00:05:47,330 what's going on. 77 00:05:47,460 --> 00:05:50,360 This kind of stuff is really important to understand. 78 00:05:50,490 --> 00:05:56,160 It's basic nitty gritty foundational stuff can be boring but it's important to understand you can't 79 00:05:56,160 --> 00:05:58,890 understand networking if you don't understand the stuff. 80 00:05:58,890 --> 00:06:04,830 So spend the time learning your protocols you will need to put in the effort and spend time learning 81 00:06:04,830 --> 00:06:10,350 your protocols if you really want to understand networking if you want to become an ethical hacker you 82 00:06:10,350 --> 00:06:14,760 need to understand the protocol so that you can hack them if you want to become a network engineer you 83 00:06:14,760 --> 00:06:20,580 need to understand the protocols to be able to configure network devices properly and troubleshoot network 84 00:06:20,580 --> 00:06:25,950 devices or troubleshoot network issues if you want to become an a good application developer you need 85 00:06:25,950 --> 00:06:31,650 to have an understanding of the underlying applications many nightmares are caused today for network 86 00:06:31,650 --> 00:06:37,350 engineers because of badly written applications application developers assume some of them who write 87 00:06:37,350 --> 00:06:43,500 bad applications that there's unlimited bandwidth there is no unlimited bandwidth if you write a per 88 00:06:43,500 --> 00:06:50,310 application it's going to make a network engineer's life very difficult as a lot of old network engineers 89 00:06:50,310 --> 00:06:57,120 will say it's always the networks fault and all the rubbish comes from the top and lands on our heads 90 00:06:57,480 --> 00:07:02,910 because people will blame the network even when there's an application that's at fault make sure that 91 00:07:02,910 --> 00:07:08,160 you spend your time learning your protocols so that you can prove it's not a network issue but it's 92 00:07:08,160 --> 00:07:09,150 an application issue.