1 1 00:00:00,430 --> 00:00:02,460 So, in this lesson, I wanted to show you 2 2 00:00:02,460 --> 00:00:04,460 what some of these antennas look like 3 3 00:00:04,460 --> 00:00:06,270 with more of a hands-on approach. 4 4 00:00:06,270 --> 00:00:08,380 So, let's go ahead and start with what's called 5 5 00:00:08,380 --> 00:00:11,120 an omnidirectional antenna, and this is what you have 6 6 00:00:11,120 --> 00:00:13,120 in most of your wireless access points 7 7 00:00:13,120 --> 00:00:15,030 and most of your wireless devices. 8 8 00:00:15,030 --> 00:00:18,120 So, if I take, for instance, this old cellphone. 9 9 00:00:18,120 --> 00:00:20,630 This old cell phone has a Wi-Fi connection 10 10 00:00:20,630 --> 00:00:22,210 inside of it, built in. 11 11 00:00:22,210 --> 00:00:23,760 It actually is an Android cellphone 12 12 00:00:23,760 --> 00:00:26,850 and it has the ability to either receive a wireless signal 13 13 00:00:26,850 --> 00:00:30,010 through Wi-Fi or put one out as a hotspot 14 14 00:00:30,010 --> 00:00:33,110 and then allow other devices to connect through wifi to it 15 15 00:00:33,110 --> 00:00:35,370 and then go out through its cellular connection 16 16 00:00:35,370 --> 00:00:36,980 to get access to the Internet. 17 17 00:00:36,980 --> 00:00:39,130 Now, you'll notice, when I was talking about this cellphone, 18 18 00:00:39,130 --> 00:00:41,350 I mentioned it's omnidirectional. 19 19 00:00:41,350 --> 00:00:42,830 And that makes sense for a cellphone 20 20 00:00:42,830 --> 00:00:44,610 because as you're walking around, 21 21 00:00:44,610 --> 00:00:45,990 you don't know which direction 22 22 00:00:45,990 --> 00:00:47,490 the signal's going to be coming from. 23 23 00:00:47,490 --> 00:00:50,400 So, instead, it's going to send and receive data 24 24 00:00:50,400 --> 00:00:52,650 both up and down, left and right, 25 25 00:00:52,650 --> 00:00:55,330 forward and back, in every single direction, 26 26 00:00:55,330 --> 00:00:57,300 with equal power to be able to connect 27 27 00:00:57,300 --> 00:00:59,210 to the local wireless access point 28 28 00:00:59,210 --> 00:01:00,850 or the local cellular tower, 29 29 00:01:00,850 --> 00:01:03,210 depending on which frequencies we're using. 30 30 00:01:03,210 --> 00:01:04,730 Now, this is the same thing that happens 31 31 00:01:04,730 --> 00:01:06,690 with your wireless access points, too. 32 32 00:01:06,690 --> 00:01:08,840 So, for instance, if I take this old 33 33 00:01:08,840 --> 00:01:11,180 wireless access point from Netgear, 34 34 00:01:11,180 --> 00:01:13,200 you'll see this is actually a combination device 35 35 00:01:13,200 --> 00:01:17,030 of a router, a switch, as well as a wireless access point. 36 36 00:01:17,030 --> 00:01:18,770 There's no external antenna. 37 37 00:01:18,770 --> 00:01:21,790 Instead, they're using an internal omnidirectional antenna 38 38 00:01:21,790 --> 00:01:23,390 just like that cellphone did. 39 39 00:01:23,390 --> 00:01:25,080 And so, in every single direction, 40 40 00:01:25,080 --> 00:01:26,750 we're going to be sending data out 41 41 00:01:26,750 --> 00:01:29,780 to be able to get data out equally in all directions. 42 42 00:01:29,780 --> 00:01:32,670 So, if I want to make sure that this doesn't bleed over, 43 43 00:01:32,670 --> 00:01:35,230 if I'm in a townhouse or an apartment, for instance, 44 44 00:01:35,230 --> 00:01:37,740 I'd want to put it closer to the center of my apartment, 45 45 00:01:37,740 --> 00:01:39,810 because if I put it on one of the walls, 46 46 00:01:39,810 --> 00:01:41,210 it's going to go out in every direction, 47 47 00:01:41,210 --> 00:01:44,030 including through the wall and into my neighbor's apartment. 48 48 00:01:44,030 --> 00:01:45,280 And so, you might want to consider 49 49 00:01:45,280 --> 00:01:47,250 that from a security perspective. 50 50 00:01:47,250 --> 00:01:49,600 Now, some of the more expensive wireless devices 51 51 00:01:49,600 --> 00:01:52,510 are going to give you the ability to change out your antenna. 52 52 00:01:52,510 --> 00:01:54,200 So, for example, we talked earlier 53 53 00:01:54,200 --> 00:01:56,900 about this combination device that I got from Verizon. 54 54 00:01:56,900 --> 00:01:59,220 And inside this one, we did have the ability 55 55 00:01:59,220 --> 00:02:00,960 to connect a different antenna. 56 56 00:02:00,960 --> 00:02:04,040 So, normally, it's going to come with an antenna like this, 57 57 00:02:04,040 --> 00:02:05,987 which is a standard little whip antenna 58 58 00:02:05,987 --> 00:02:08,770 and this is considered an omnidirectional antenna. 59 59 00:02:08,770 --> 00:02:10,910 So, as I connect that on there, 60 60 00:02:10,910 --> 00:02:12,450 I'm going to be able to send data out 61 61 00:02:12,450 --> 00:02:16,130 in every direction, all 360 degrees. 62 62 00:02:16,130 --> 00:02:17,960 Now, this is a rather small antenna, 63 63 00:02:17,960 --> 00:02:19,700 so it's not going to have as much power. 64 64 00:02:19,700 --> 00:02:21,950 Maybe I wanted to get my signal to go out further. 65 65 00:02:21,950 --> 00:02:23,747 Well, I can actually change that. 66 66 00:02:23,747 --> 00:02:25,850 And I can take that antenna off 67 67 00:02:25,850 --> 00:02:28,280 and I can put on a bigger antenna. 68 68 00:02:28,280 --> 00:02:30,240 And with the bigger antenna, I'm actually going to be able 69 69 00:02:30,240 --> 00:02:33,370 to send data out a little bit farther than I could before, 70 70 00:02:33,370 --> 00:02:34,900 because the longer the antenna, 71 71 00:02:34,900 --> 00:02:37,490 the more propagation you're going to get from it. 72 72 00:02:37,490 --> 00:02:40,340 Now, also, when I'm doing wireless attacks 73 73 00:02:40,340 --> 00:02:42,230 and wireless hacking and pentests, 74 74 00:02:42,230 --> 00:02:43,840 I actually have a wireless card 75 75 00:02:43,840 --> 00:02:46,330 that I use with my laptop and that has the ability 76 76 00:02:46,330 --> 00:02:48,900 for me to change the antenna, as well. 77 77 00:02:48,900 --> 00:02:51,690 And so, I would take this wireless card 78 78 00:02:51,690 --> 00:02:54,060 and I would screw on whichever antenna I want. 79 79 00:02:54,060 --> 00:02:56,370 So, if I want more distance or more power, 80 80 00:02:56,370 --> 00:02:58,900 I can go ahead and use an omnidirectional antenna 81 81 00:02:58,900 --> 00:03:02,010 like this, screw it on, connect this through USB 82 82 00:03:02,010 --> 00:03:05,030 back to my laptop, and now, I have this antenna 83 83 00:03:05,030 --> 00:03:07,420 radiating out in every direction. 84 84 00:03:07,420 --> 00:03:08,660 Now, I've spent a lot of time talking 85 85 00:03:08,660 --> 00:03:10,300 about omnidirectional antennas, 86 86 00:03:10,300 --> 00:03:11,480 but what do you do if you want to 87 87 00:03:11,480 --> 00:03:13,650 make it go in a single direction? 88 88 00:03:13,650 --> 00:03:16,030 For example, when I'm doing wireless pentesting, 89 89 00:03:16,030 --> 00:03:18,770 often, omnidirectional is not the best way to go 90 90 00:03:18,770 --> 00:03:21,370 because when you're putting power out in all directions, 91 91 00:03:21,370 --> 00:03:23,500 you're limited in how far you can go. 92 92 00:03:23,500 --> 00:03:26,660 But if I can focus my power in just one direction, 93 93 00:03:26,660 --> 00:03:29,840 that's called unidirectional, I can actually focus 94 94 00:03:29,840 --> 00:03:31,850 all the power out the left side of the antenna 95 95 00:03:31,850 --> 00:03:33,480 or the right side of the antenna. 96 96 00:03:33,480 --> 00:03:36,290 And that way, I can push all of the power one way 97 97 00:03:36,290 --> 00:03:38,250 and no signal goes out the other. 98 98 00:03:38,250 --> 00:03:40,330 So again, going back to the apartment example, 99 99 00:03:40,330 --> 00:03:42,720 if I'm up against the right wall of the building 100 100 00:03:42,720 --> 00:03:45,010 and I have a directional antenna pushing 101 101 00:03:45,010 --> 00:03:48,340 all the power out left, it's going to go into my apartment 102 102 00:03:48,340 --> 00:03:51,590 and not into my neighbor's, because we have that right wall. 103 103 00:03:51,590 --> 00:03:53,750 That's using a unidirectional antenna. 104 104 00:03:53,750 --> 00:03:55,750 And we have unidirectional left, 105 105 00:03:55,750 --> 00:03:57,990 unidirectional right, and things like that, 106 106 00:03:57,990 --> 00:04:00,770 so we can choose which direction we're going to be using. 107 107 00:04:00,770 --> 00:04:02,980 Now, the other thing when we're dealing with antennas 108 108 00:04:02,980 --> 00:04:04,840 you have to think about is what are some 109 109 00:04:04,840 --> 00:04:06,970 of the other types of antennas that are out there? 110 110 00:04:06,970 --> 00:04:10,470 Besides the standard unidirectional and omnidirectional, 111 111 00:04:10,470 --> 00:04:13,800 uni meaning one, omni meaning all, 112 112 00:04:13,800 --> 00:04:16,640 we also have things known as parabolic. 113 113 00:04:16,640 --> 00:04:19,940 Now, parabolic are a special type of unidirectional. 114 114 00:04:19,940 --> 00:04:22,610 Parabolic is going to give it a different curvature 115 115 00:04:22,610 --> 00:04:24,150 to the way the signal's going to go out, 116 116 00:04:24,150 --> 00:04:27,120 and it's most often used with microwave signals, 117 117 00:04:27,120 --> 00:04:29,070 as well as satellite TV signals, 118 118 00:04:29,070 --> 00:04:31,890 as you could see here on this particular antenna. 119 119 00:04:31,890 --> 00:04:33,490 Now, this is a DIRECTV antenna 120 120 00:04:33,490 --> 00:04:35,000 on one of my neighbor's houses 121 121 00:04:35,000 --> 00:04:36,637 that I drove by and took a picture of for you. 122 122 00:04:36,637 --> 00:04:38,040 And you can see that curvature 123 123 00:04:38,040 --> 00:04:39,960 of the dish which is going to focus 124 124 00:04:39,960 --> 00:04:42,240 the energy up and towards the satellite 125 125 00:04:42,240 --> 00:04:44,850 and not out in every other direction. 126 126 00:04:44,850 --> 00:04:48,090 Finally, I want you to consider this other antenna here. 127 127 00:04:48,090 --> 00:04:50,350 This one is actually in the UHF band, 128 128 00:04:50,350 --> 00:04:52,210 which is a frequency band that we use, 129 129 00:04:52,210 --> 00:04:55,760 and it used to be used a lot for TV before we had cable. 130 130 00:04:55,760 --> 00:04:57,780 You'd have UHF and VHF. 131 131 00:04:57,780 --> 00:05:00,140 Now, with this antenna, you can also see 132 132 00:05:00,140 --> 00:05:01,990 that it is a very directional antenna. 133 133 00:05:01,990 --> 00:05:03,270 You could see how it's pointing 134 134 00:05:03,270 --> 00:05:05,360 in one direction, almost like an arrow. 135 135 00:05:05,360 --> 00:05:08,190 That's going to allow it to get a further reach to that signal, 136 136 00:05:08,190 --> 00:05:10,700 to that TV transmitter that's sending it out. 137 137 00:05:10,700 --> 00:05:12,700 Now, do we use these anymore? 138 138 00:05:12,700 --> 00:05:14,170 Well, sometimes. 139 139 00:05:14,170 --> 00:05:16,430 These actually can be used to point 140 140 00:05:16,430 --> 00:05:19,950 and push a wireless signal over a longer distance. 141 141 00:05:19,950 --> 00:05:22,440 So, if you're in a business park or a campus setting, 142 142 00:05:22,440 --> 00:05:25,330 you might see some of these antennas on top of buildings 143 143 00:05:25,330 --> 00:05:27,570 pointing from one building to the other, 144 144 00:05:27,570 --> 00:05:29,960 using this unidirectional antenna. 145 145 00:05:29,960 --> 00:05:33,030 And in this case, this is actually known as a Yagi antenna, 146 146 00:05:33,030 --> 00:05:36,690 Y-A-G-I, and it allows them to have a very directional, 147 147 00:05:36,690 --> 00:05:39,890 focused beam going from one building to another. 148 148 00:05:39,890 --> 00:05:41,600 So, if you hear the term Yagi, 149 149 00:05:41,600 --> 00:05:44,290 that is going to be something that is a directional antenna, 150 150 00:05:44,290 --> 00:05:47,220 unidirectional antenna, going one way. 151 151 00:05:47,220 --> 00:05:48,430 Now, if you hear about parabolic, 152 152 00:05:48,430 --> 00:05:50,170 I want you to think about that satellite TV, 153 153 00:05:50,170 --> 00:05:52,200 that curved dish that's pointing 154 154 00:05:52,200 --> 00:05:55,000 that directional back towards the satellite. 155 155 00:05:55,000 --> 00:05:56,560 And if you think about omnidirectional, 156 156 00:05:56,560 --> 00:05:58,640 I want you to think about these embedded devices. 157 157 00:05:58,640 --> 00:06:00,550 Things like your wireless access point 158 158 00:06:00,550 --> 00:06:02,340 or things like your cellphone 159 159 00:06:02,340 --> 00:06:04,090 or things like your wireless card 160 160 00:06:04,090 --> 00:06:05,970 with a long antenna like this one. 161 161 00:06:05,970 --> 00:06:07,060 But this is just the idea. 162 162 00:06:07,060 --> 00:06:08,440 There's different types of antennas 163 163 00:06:08,440 --> 00:06:10,510 used for different situations, 164 164 00:06:10,510 --> 00:06:12,440 and it all depends on what you're going to do. 165 165 00:06:12,440 --> 00:06:14,760 Now, for the exam, you want to be able to know 166 166 00:06:14,760 --> 00:06:17,500 when you should use an omnidirectional antenna 167 167 00:06:17,500 --> 00:06:20,110 or when you should use a directional antenna 168 168 00:06:20,110 --> 00:06:22,040 or when you should use something that attaches 169 169 00:06:22,040 --> 00:06:24,560 to the side of a building, like a patch antenna, 170 170 00:06:24,560 --> 00:06:26,840 which is a small, circular dish 171 171 00:06:26,840 --> 00:06:29,630 that is able to go on one side of the building to another, 172 172 00:06:29,630 --> 00:06:32,210 and they can point at each other in a directional manner. 173 173 00:06:32,210 --> 00:06:33,700 These are different types of antennas 174 174 00:06:33,700 --> 00:06:35,440 that you may come across when dealing 175 175 00:06:35,440 --> 00:06:37,230 with wireless networks and they're important 176 176 00:06:37,230 --> 00:06:39,193 to understand before you take the exam.