WEBVTT 1 00:00:00.000 --> 00:00:03.680 All right, so you want to like really up your 2 00:00:03.879 --> 00:00:07.519 Unix and Linux system administration game, Well, today's deep dive 3 00:00:07.599 --> 00:00:10.160 is going to be your secret weapon. We're going deep 4 00:00:10.199 --> 00:00:15.400 into the UNX and Linux System Administration Handbook. And trust me, 5 00:00:15.439 --> 00:00:18.640 this is not just some dry like textbook recap note. 6 00:00:18.679 --> 00:00:22.199 We're extracting like the good stuff, the real aha moments, 7 00:00:22.399 --> 00:00:24.960 the things that will actually make you a better sissed men. 8 00:00:25.399 --> 00:00:27.440 You know what's really fascinating about this book is it's 9 00:00:27.440 --> 00:00:30.600 almost like a historical artifact. Like it literally started as 10 00:00:30.600 --> 00:00:32.799 a way to gather all this wisdom from these early 11 00:00:32.920 --> 00:00:36.439 Unix gurus back when documentation was like practically non existent. 12 00:00:36.920 --> 00:00:38.799 It's pretty amazing to see how the field has like 13 00:00:38.880 --> 00:00:39.880 evolved since then. 14 00:00:40.039 --> 00:00:42.159 Oh wow, you know that's a really good point. I 15 00:00:42.159 --> 00:00:44.439 hadn't actually thought about that, and it really highlights how 16 00:00:44.520 --> 00:00:48.399 even the most complex systems they start somewhere. Often some 17 00:00:48.439 --> 00:00:50.719 would just be like, hey, let's write this down totally. 18 00:00:50.880 --> 00:00:53.560 And from those humble beginnings we've arrived at these intricate 19 00:00:53.600 --> 00:00:56.520 systems we manage today. But to really understand them, we 20 00:00:56.560 --> 00:01:00.799 need to start with the fundamentals like user accounts, permission backups, 21 00:01:00.840 --> 00:01:01.560 and networking. 22 00:01:01.920 --> 00:01:04.640 Yeah, those do sound like the essential building blocks, but 23 00:01:04.760 --> 00:01:07.879 let's face it, the command line can be intimidating even 24 00:01:07.920 --> 00:01:11.599 for experienced cisigmins. And I see the book mentions scripting, 25 00:01:12.280 --> 00:01:14.239 is that the key to kind of taming this beast? 26 00:01:14.560 --> 00:01:17.239 Scripting? Oh yeah, scripting is definitely a powerhouse tool and 27 00:01:17.280 --> 00:01:21.439 Assissimin's arsenal. It's all about automating those repetitive tasks, the 28 00:01:21.480 --> 00:01:24.120 ones that can like eat up hours of your time. 29 00:01:24.519 --> 00:01:27.159 So the book dives into shell scripting, which is like 30 00:01:27.200 --> 00:01:29.439 creating mini programs to tell your system what to do, 31 00:01:29.719 --> 00:01:32.319 and then it takes you even further with Perl and Python. 32 00:01:32.560 --> 00:01:35.920 Pearl and Python. Those are those popular scripting languages, right, Yeah, 33 00:01:35.959 --> 00:01:38.319 I've heard they can be life savers for assissigmins. 34 00:01:38.400 --> 00:01:42.040 Oh, they absolutely can. Like imagine automating user creation or 35 00:01:42.079 --> 00:01:45.760 backups or even like system monitoring. That's the power these 36 00:01:45.840 --> 00:01:46.599 languages give you. 37 00:01:46.799 --> 00:01:49.280 Okay, I'm starting to see how powerful that could be. Yeah, 38 00:01:49.319 --> 00:01:52.159 but before we like get lost in this world of automation, 39 00:01:52.280 --> 00:01:55.640 let's talk about keeping those users data safe. Backups that's 40 00:01:55.680 --> 00:01:56.920 got to be like a top priority. 41 00:01:57.040 --> 00:02:01.319 Right, Oh, you're totally right. Backups are non gooshable. The 42 00:02:01.319 --> 00:02:03.760 book goes beyond just saying back up your data. It 43 00:02:03.799 --> 00:02:08.080 goes into like different strategies, full backups, incremental backups. It 44 00:02:08.120 --> 00:02:10.360 even breaks down the pros and cons of different media 45 00:02:10.439 --> 00:02:13.960 like tape versus optical discs. And then there's software like 46 00:02:14.120 --> 00:02:15.240 Bacula vacula. 47 00:02:15.319 --> 00:02:19.080 Okay, but why Baculu specifically? What makes it stand out 48 00:02:19.120 --> 00:02:20.520 from other backup solutions. 49 00:02:21.319 --> 00:02:24.639 Well, Bacula is open source. It's a network backup solution 50 00:02:24.800 --> 00:02:27.439 designed to be like super scalable and flexible. It can 51 00:02:27.479 --> 00:02:30.800 handle a wide range of scenarios from like single workstations 52 00:02:30.840 --> 00:02:34.280 to large networks with tons of different operating systems. The 53 00:02:34.319 --> 00:02:38.919 book highlights its features for managing that entire backup process, scheduling, 54 00:02:39.159 --> 00:02:41.879 data verification, and even disaster recovery. 55 00:02:41.960 --> 00:02:44.159 So it's like a Swiss army knife for backups, able 56 00:02:44.199 --> 00:02:46.439 to handle pretty much anything you throw at it. Definitely 57 00:02:46.439 --> 00:02:49.479 adding that to my list to explore further. Now, switching 58 00:02:49.479 --> 00:02:51.800 gears a bit, let's talk networking. That's always seemed a 59 00:02:51.840 --> 00:02:52.680 bit like magic to me. 60 00:02:53.039 --> 00:02:56.479 Networking can seem a bit daunting, but the book demystifies 61 00:02:56.520 --> 00:02:59.759 it by focusing on the core TCPIP. This is like 62 00:02:59.800 --> 00:03:02.280 the language of the Internet, and the book provides a 63 00:03:02.319 --> 00:03:07.199 solid grounding in like IP addresses subnets, routing the whole 64 00:03:07.280 --> 00:03:08.960 nine yards TCPIP. 65 00:03:09.199 --> 00:03:11.280 Right, I've seen that term but never really understood what 66 00:03:11.319 --> 00:03:14.080 it's all about. So if it's the language of the Internet, 67 00:03:14.240 --> 00:03:16.919 is it like a set of rules that computers use 68 00:03:17.039 --> 00:03:18.479 to like talk to each other. 69 00:03:18.719 --> 00:03:20.560 That's a great way to put it. Yeah, it's a 70 00:03:20.599 --> 00:03:23.919 whole suite of protocols that dictates how data is packaged, addressed, 71 00:03:23.919 --> 00:03:26.319 and delivered across the Internet. And the book breaks it 72 00:03:26.360 --> 00:03:29.759 down into layers, making it way easier to understand layers. 73 00:03:30.080 --> 00:03:31.840 Like an onion sensing a. 74 00:03:31.800 --> 00:03:34.919 Theme here, Exactly, each layer handles a specific part of 75 00:03:34.919 --> 00:03:37.840 that communication process. You have the physical layer dealing with 76 00:03:37.879 --> 00:03:39.800 cables and signals, and then you go up to the 77 00:03:39.840 --> 00:03:43.159 application layer where things like email and web browsing actually happen. 78 00:03:43.319 --> 00:03:46.800 So this layered approach, it helps break down the complexity 79 00:03:46.840 --> 00:03:49.919 of networking, right, So it's easier to troubleshoot when things 80 00:03:49.960 --> 00:03:50.479 go wrong. 81 00:03:50.680 --> 00:03:52.840 Exactly when you get the role of each layer, you 82 00:03:52.879 --> 00:03:55.199 can pinpoint problems way more effectively. 83 00:03:55.479 --> 00:03:57.479 That makes a lot of sense. What about all those 84 00:03:57.560 --> 00:04:02.919 other networking acronyms you always hear DHCP DNS. Those always 85 00:04:02.919 --> 00:04:05.159 seemed a bit like blackmagic to me. 86 00:04:05.479 --> 00:04:08.719 Well, those are essential services that actually make the Internet usable. 87 00:04:09.000 --> 00:04:13.400 DHCP stands for Dynamic Host Configuration Protocol, and it automatically 88 00:04:13.439 --> 00:04:17.279 assigns IP addresses to devices on a network. Imagine having 89 00:04:17.319 --> 00:04:21.160 to configure IP addresses manually for every device on a network. 90 00:04:21.199 --> 00:04:23.800 It would be a total nightmare. DHCP takes care of 91 00:04:23.800 --> 00:04:24.279 that for us. 92 00:04:24.360 --> 00:04:28.519 Okay, so DHDP streamlines that process, making everyone's lives much easier. 93 00:04:28.959 --> 00:04:30.920 What about DNS? What role does it play in this 94 00:04:30.959 --> 00:04:32.160 whole interconnected world. 95 00:04:32.519 --> 00:04:34.600 DNS, or the Domain Name system, is like the phone 96 00:04:34.639 --> 00:04:37.480 book of the Internet. It translates those human readable domain 97 00:04:37.560 --> 00:04:41.000 names like Google dot com into numerical IP addresses that 98 00:04:41.040 --> 00:04:42.279 computers can actually use. 99 00:04:42.600 --> 00:04:45.000 Ah so at i type Google dot com into my browser, 100 00:04:45.399 --> 00:04:47.319 DNS is working in the background to figure out where 101 00:04:47.319 --> 00:04:47.720 to send. 102 00:04:47.560 --> 00:04:51.279 My request exactly. Without DNS, we'd be stuck memorizing long 103 00:04:51.319 --> 00:04:54.160 strings of numbers just to visit our favorite websites. Not 104 00:04:54.439 --> 00:04:56.160 very user friendly, not at all. 105 00:04:56.639 --> 00:04:59.000 I'm starting to see how these different protocols and services 106 00:04:59.040 --> 00:05:03.920 all work together to create this seamless Internet experience we 107 00:05:04.040 --> 00:05:05.079 usually take for granted. 108 00:05:05.199 --> 00:05:07.680 And the book doesn't stop there. It takes you further 109 00:05:07.800 --> 00:05:10.879 down the networking rabbit hole. It explains stuff like routing 110 00:05:11.000 --> 00:05:14.160 and how data packets travel across different networks to reach 111 00:05:14.199 --> 00:05:14.839 their destination. 112 00:05:15.199 --> 00:05:18.079 Routing, Okay, that's where routers come in, right, those little 113 00:05:18.120 --> 00:05:19.680 boxes that connect us to the Internet. 114 00:05:19.720 --> 00:05:23.000 You got it. Routers are like traffic cops, directing those 115 00:05:23.040 --> 00:05:26.279 data packets along the most efficient path. And the book 116 00:05:26.319 --> 00:05:31.079 goes into different routing protocols like rip, OSPF and BGP, 117 00:05:31.519 --> 00:05:35.639 which determine how those routers actually communicate and share information 118 00:05:35.879 --> 00:05:36.720 about the network. 119 00:05:37.040 --> 00:05:39.920 So it's like this whole communication system happening behind the scenes, 120 00:05:40.199 --> 00:05:42.160 making sure that data gets where it needs to go 121 00:05:42.240 --> 00:05:43.839 as quickly and reliably as possible. 122 00:05:44.000 --> 00:05:47.319 Exactly, And the book gives you the knowledge to understand 123 00:05:47.360 --> 00:05:49.279 and manage these complex systems. 124 00:05:49.680 --> 00:05:52.639 This is already so much more than just a basic overview. 125 00:05:53.000 --> 00:05:54.879 I'm actually starting to feel like I'm getting a handle 126 00:05:54.879 --> 00:05:57.120 on some of these concepts. But hold on, before we 127 00:05:57.160 --> 00:05:58.720 go to the next topic, I want to go back 128 00:05:58.720 --> 00:06:02.480 to something you mentioned earlier about the book's historical perspective. 129 00:06:02.920 --> 00:06:06.040 Can you tell me more about how system administration has 130 00:06:06.079 --> 00:06:07.920 evolved since those early days. 131 00:06:08.199 --> 00:06:11.519 That's a great question. One of the biggest changes has 132 00:06:11.600 --> 00:06:15.600 been the shift away from those traditional partitioning approaches to 133 00:06:15.720 --> 00:06:20.160 more flexible solutions like logical volume management or LVM. 134 00:06:20.279 --> 00:06:23.959 Okay, traditional partitioning. That sounds vaguely familiar. Can you remind 135 00:06:24.000 --> 00:06:24.480 me what that is? 136 00:06:24.600 --> 00:06:28.240 Imagine slicing a hard disk into fixed size sections, like 137 00:06:28.319 --> 00:06:31.279 pieces of a pie. Each slice would have its own 138 00:06:31.319 --> 00:06:34.079 device file, and that's how you'd manage your storage space. 139 00:06:34.360 --> 00:06:36.879 So LVM is like having a magical pie pan that 140 00:06:36.920 --> 00:06:40.199 can resize. You can adjust the slices without having to 141 00:06:40.240 --> 00:06:41.319 rebake the whole pie. 142 00:06:41.480 --> 00:06:42.560 I love that analogy. 143 00:06:42.600 --> 00:06:43.199 That's perfect. 144 00:06:43.560 --> 00:06:47.120 LVM lets you create virtual partitions. They're called logical volumes, 145 00:06:47.160 --> 00:06:50.079 and they can span multiple physical discs. You can grow 146 00:06:50.199 --> 00:06:53.279 or shrink them as needed, giving you way more flexibility 147 00:06:53.319 --> 00:06:53.920 and control. 148 00:06:54.160 --> 00:06:56.800 That definitely sounds like a huge improvement over the rigid 149 00:06:56.839 --> 00:06:58.439 structure of traditional partitioning. 150 00:06:58.560 --> 00:07:01.199 Oh it is, And the book into detail about how 151 00:07:01.319 --> 00:07:05.839 LVM actually works, explaining things like volume groups and physical extents. 152 00:07:06.319 --> 00:07:09.959 So LVM is all about creating this virtual layer on 153 00:07:10.000 --> 00:07:13.319 top of those physical discs, giving us more power and 154 00:07:13.399 --> 00:07:17.120 flexibility in managing storage space. I'm starting to see how 155 00:07:17.160 --> 00:07:19.240 that would be a game changer for system administration. 156 00:07:19.360 --> 00:07:22.439 Absolutely, and it's just one example of how this field 157 00:07:22.480 --> 00:07:25.240 has evolved to meet the growing demands of modern computing. 158 00:07:25.600 --> 00:07:28.199 This is already so much more than I expected. I'm 159 00:07:28.199 --> 00:07:30.000 starting to feel like I'm getting a real handle on 160 00:07:30.040 --> 00:07:33.120 these concepts. But we've covered a ton of ground already, 161 00:07:33.439 --> 00:07:36.800 from scripting to backups to the evolution of storage management. 162 00:07:37.160 --> 00:07:38.680 I think it's time to take a break and let 163 00:07:38.720 --> 00:07:41.079 all this information sink in. We'll be back soon to 164 00:07:41.079 --> 00:07:45.040 continue our deep dives, so don't go anywhere, Okay, welcome back. 165 00:07:45.680 --> 00:07:48.360 Before the break, we were talking about how system administration 166 00:07:48.399 --> 00:07:52.199 has evolved, especially with that shift from traditional partitioning to LVM. 167 00:07:53.040 --> 00:07:56.399 Now I'm curious how the book tackles file systems. After all, 168 00:07:56.480 --> 00:07:59.319 those who are kind of the backbone of any operating system. 169 00:07:59.079 --> 00:08:02.000 Right, Yeah, sure, filesystems are super important. But you're right 170 00:08:02.040 --> 00:08:03.959 if you're a seasoned system and you probably already have 171 00:08:03.959 --> 00:08:07.240 a good basic understanding. What's interesting is this book doesn't 172 00:08:07.279 --> 00:08:10.920 just rehash the basics. It digs into all these different 173 00:08:10.959 --> 00:08:15.399 filesystem types like X three, XT four, even ZFS, and 174 00:08:15.439 --> 00:08:18.720 how to really manage them to get the best performance, So. 175 00:08:18.680 --> 00:08:21.839 It's assuming we know the difference between like FAT thirty 176 00:08:21.839 --> 00:08:24.720 two and ntfs. But then it goes deeper into the 177 00:08:24.720 --> 00:08:25.920 options specifically for. 178 00:08:25.959 --> 00:08:29.399 Unix and Linux exactly, and it goes beyond just the 179 00:08:29.399 --> 00:08:31.480 technical stuff. It looks at the pros and cons of 180 00:08:31.480 --> 00:08:34.799 each filesystem so you can decide what's best for your needs. 181 00:08:35.320 --> 00:08:38.000 For instance, it talks about how journaling in X three 182 00:08:38.039 --> 00:08:40.720 and X four makes your data more reliable, which is 183 00:08:40.799 --> 00:08:43.120 super important for keeping your system stable. 184 00:08:43.240 --> 00:08:45.919 Journaling Okay, I've heard that term but never really understood 185 00:08:45.960 --> 00:08:46.399 what it meant. 186 00:08:46.440 --> 00:08:48.279 Think of it like a safety net for your data. 187 00:08:48.360 --> 00:08:50.639 It keeps track of all the changes to the filesystem, 188 00:08:50.679 --> 00:08:54.360 so if your system crashes, it can recover without losing anything. 189 00:08:54.559 --> 00:08:57.799 That sounds pretty crucial, especially for servers where losing data 190 00:08:57.840 --> 00:08:58.679 could be a disaster. 191 00:08:59.120 --> 00:09:02.080 Oh absolutely, And the book doesn't shy away from newer 192 00:09:02.120 --> 00:09:05.519 technologies either. It even talks about iSCSI, which has become 193 00:09:05.759 --> 00:09:07.279 super important data centers. 194 00:09:07.399 --> 00:09:11.960 Right iSCSI that lets you connect to storage over the network, 195 00:09:12.360 --> 00:09:15.759 basically creating these virtual hard drives. But how does that 196 00:09:15.799 --> 00:09:18.200 actually work? Is it as simple as plugging in a 197 00:09:18.240 --> 00:09:18.960 network cable? 198 00:09:19.159 --> 00:09:22.080 Well it's not quite that simple, but The book does 199 00:09:22.080 --> 00:09:25.759 a pretty good job of explaining it. Basically, iSCSI uses 200 00:09:25.759 --> 00:09:30.159 your network to transmit SCSI commands, so you can access 201 00:09:30.200 --> 00:09:32.879 storage on a totally different server as if it were 202 00:09:32.879 --> 00:09:33.559 a local disc. 203 00:09:33.919 --> 00:09:36.519 So instead of being limited by the storage on one server, 204 00:09:36.879 --> 00:09:38.360 I can use storage from anywhere on. 205 00:09:38.320 --> 00:09:41.039 The network exactly. It opens up a lot of possibilities 206 00:09:41.039 --> 00:09:43.720 for scaling up your system and being more flexible. You 207 00:09:43.759 --> 00:09:46.840 can add or remove storage without having to physically install 208 00:09:46.960 --> 00:09:47.559 new hardware. 209 00:09:47.639 --> 00:09:49.799 Okay, I'm starting to get it. Let's focus back on 210 00:09:49.840 --> 00:09:52.519 a single system for a minute. The book also mentions 211 00:09:52.519 --> 00:09:55.879 device drivers. Those are like instruction manuals for your hardware. 212 00:09:55.600 --> 00:09:57.360 Right, Yeah, that's a good way to think about it. 213 00:09:58.159 --> 00:10:01.080 They're the software that allows the I operating system to 214 00:10:01.240 --> 00:10:03.759 talk to and control the different parts of your hardware. 215 00:10:04.159 --> 00:10:06.879 Think of them like translators. They let the operating system 216 00:10:06.960 --> 00:10:09.000 speak the language of all those different devices. 217 00:10:09.240 --> 00:10:11.720 So when I plug in a new printer, my operating 218 00:10:11.759 --> 00:10:13.720 system needs the right driver to know how to. 219 00:10:13.799 --> 00:10:16.879 Use it exactly, And the book goes into detail about 220 00:10:16.879 --> 00:10:19.879 how drivers work, how to install them, and even how 221 00:10:19.879 --> 00:10:21.919 to tweak them to get the best performance. 222 00:10:22.200 --> 00:10:25.519 But aren't there different kinds of drivers. I vaguely remember 223 00:10:25.559 --> 00:10:28.600 something about character devices and block devices. 224 00:10:28.679 --> 00:10:32.879 You're right. The book explains that difference. Character devices handle 225 00:10:33.000 --> 00:10:35.519 data one byte at a time, like your keyboard or 226 00:10:35.559 --> 00:10:39.320 a serial port. Block devices deal with data in blocks, 227 00:10:39.679 --> 00:10:41.679 like hard drives and USB drives. 228 00:10:41.879 --> 00:10:43.960 So it's all about how the data is sent between 229 00:10:43.960 --> 00:10:46.720 the hardware and the operating system. But how do these 230 00:10:46.799 --> 00:10:49.320 drivers actually get loaded into the kernel. 231 00:10:49.480 --> 00:10:52.679 Ah, that's where lkams come in, loadable kernel modules. They're 232 00:10:52.720 --> 00:10:55.080 basically bits of code that you can load into the 233 00:10:55.120 --> 00:10:57.919 kernel while it's running, so you can add new functionality 234 00:10:57.919 --> 00:10:59.080 without having to reboot. 235 00:10:59.240 --> 00:11:01.279 So if I need to install a new driver, I 236 00:11:01.279 --> 00:11:03.639 don't have to shut down a whole system in most cases. 237 00:11:03.759 --> 00:11:07.799 Nope. LKMs let you swap drivers and other kernel modules 238 00:11:07.840 --> 00:11:11.159 without rebooting. It makes the system much more flexible. 239 00:11:11.399 --> 00:11:14.639 That is super convenient. But how does the system keep 240 00:11:14.679 --> 00:11:17.240 track of all these connected devices and make sure they're 241 00:11:17.279 --> 00:11:18.039 set up correctly? 242 00:11:18.240 --> 00:11:21.600 Well? Linux has this really clever system called UDEV for that. 243 00:11:21.799 --> 00:11:25.159 It automatically detects and configures devices when you plug them 244 00:11:25.159 --> 00:11:28.360 in or unplug them. It does things like creating device 245 00:11:28.399 --> 00:11:31.279 files and loading the right drivers you DEV. 246 00:11:31.600 --> 00:11:34.639 It's like it's a detective for hardware, sniffing out new 247 00:11:34.639 --> 00:11:37.200 devices and making sure they're registered with the system. 248 00:11:37.399 --> 00:11:39.639 That's a great way to put it. You. Dev is 249 00:11:39.639 --> 00:11:41.960 a big part of what makes Linux so user friendly. 250 00:11:42.120 --> 00:11:44.759 It handles all that behind the scenes work of managing 251 00:11:44.759 --> 00:11:45.399 your hardware. 252 00:11:45.519 --> 00:11:48.440 This is really fascinating. I'm starting to understand just how 253 00:11:48.519 --> 00:11:51.360 much is going on under the surface of these operating systems. 254 00:11:51.919 --> 00:11:55.399 But let's switch gears back to networking. What about all 255 00:11:55.440 --> 00:11:59.679 those different protocols and services that make up this Internet world. 256 00:12:00.120 --> 00:12:02.559 Yeah, networking can be a bit of a jungle, but 257 00:12:02.639 --> 00:12:06.399 the book starts with the basics. TCPIP, it's the foundation 258 00:12:06.480 --> 00:12:07.159 of the Internet. 259 00:12:07.320 --> 00:12:10.320 Okay, TCPIP we touched on this before, but I'm ready 260 00:12:10.320 --> 00:12:13.759 to go deeper now. If it's the language of the Internet, 261 00:12:13.840 --> 00:12:15.600 can you explain that a bit more? Like, how does 262 00:12:15.639 --> 00:12:17.080 this language actually work? 263 00:12:17.240 --> 00:12:19.759 Imagine you're sending a letter. You need the address, you 264 00:12:19.799 --> 00:12:21.440 need to put the letter in an envelope, and you 265 00:12:21.480 --> 00:12:24.360 need a way to make sure it gets delivered. TCPIP 266 00:12:24.480 --> 00:12:27.279 does something similar for data. It has rules for addressing, 267 00:12:27.399 --> 00:12:30.759 for packaging data into packets, and for making sure those 268 00:12:30.759 --> 00:12:32.360 packets get delivered reliably. 269 00:12:32.559 --> 00:12:34.799 So Each packet is like a little envelope with a 270 00:12:34.799 --> 00:12:38.200 piece of the message and TCPIP make sure they all 271 00:12:38.320 --> 00:12:38.799 arrive in the. 272 00:12:38.840 --> 00:12:41.960 Right order exactly. And the book takes you through all 273 00:12:42.039 --> 00:12:45.399 the different layers of TCPIP, from the physical layer dealing 274 00:12:45.480 --> 00:12:48.399 with cables and signals, up to the application layer where 275 00:12:48.399 --> 00:12:50.519 things like email and web browsing happen. 276 00:12:50.639 --> 00:12:53.200 It's like a layer cake where each layer is responsible 277 00:12:53.279 --> 00:12:54.879 for a different part of the communication. 278 00:12:55.240 --> 00:12:58.320 That's a great analogy, and understanding these layers is really 279 00:12:58.399 --> 00:13:02.039 important for fixing network problems. When you know how each 280 00:13:02.159 --> 00:13:04.720 layer works, you can isolate the issue much easier. 281 00:13:04.840 --> 00:13:08.159 That makes sense. So TCPIP is the foundation, but then 282 00:13:08.519 --> 00:13:10.919 there are all these other protocols and services built on 283 00:13:10.960 --> 00:13:13.799 top of it. What about DPCP and DNS. Those always 284 00:13:13.799 --> 00:13:15.519 seems kind of mysterious. 285 00:13:15.279 --> 00:13:18.519 Right, DSHP and DNS are essential for making the Internet 286 00:13:18.600 --> 00:13:24.639 actually usable. DHCP, or Dynamic Host Configuration Protocol, automatically gives 287 00:13:24.679 --> 00:13:27.159 IP addresses to devices on your network. 288 00:13:27.279 --> 00:13:29.559 So if I didn't have DHDP, I'd have to manually 289 00:13:29.600 --> 00:13:32.720 assign an IP address to every single device on my network. 290 00:13:33.159 --> 00:13:34.039 That sounds awful. 291 00:13:34.120 --> 00:13:37.200 It would be a nightmare, honestly, DHCP makes managing your 292 00:13:37.240 --> 00:13:40.919 network much easier. And then you have DNS, the Domain 293 00:13:41.000 --> 00:13:43.519 Name system, which is like the Internet's phone book. It 294 00:13:43.600 --> 00:13:47.159 translates those human readable domain names like Google dot com 295 00:13:47.279 --> 00:13:50.320 into those numerical IP addresses that computers understand. 296 00:13:50.360 --> 00:13:53.080 Also at itype, Google dot com into my browser. DNS 297 00:13:53.120 --> 00:13:55.320 is looking at the IP address, so my computer knows 298 00:13:55.320 --> 00:13:56.919 where to send their request exactly. 299 00:13:57.320 --> 00:13:59.879 Without DNS, we'd be memorizing all these long numbers for 300 00:13:59.879 --> 00:14:00.759 every website. 301 00:14:01.120 --> 00:14:03.480 Yeah, that wouldn't be fun. So I'm starting to understand 302 00:14:03.519 --> 00:14:06.080 how these different protocols and services work together to give 303 00:14:06.159 --> 00:14:09.240 us that smooth Internet experience we usually don't even think about. 304 00:14:09.399 --> 00:14:11.639 And the book does a great job of breaking these 305 00:14:11.679 --> 00:14:14.440 concepts down and showing you how to actually configure and 306 00:14:14.480 --> 00:14:16.480 manage these services on your systems. 307 00:14:16.559 --> 00:14:19.159 So it's not just theory. It gives you practical advice 308 00:14:19.240 --> 00:14:20.559 for actually implementing this. 309 00:14:20.559 --> 00:14:24.519 Stuff for sure. It covers things like setting up DHCP servers, 310 00:14:24.960 --> 00:14:29.240 configuring DNS zones, and even gets into routing, which is 311 00:14:29.279 --> 00:14:32.399 how data actually travels across different networks to get to 312 00:14:32.440 --> 00:14:33.200 its destination. 313 00:14:33.639 --> 00:14:36.480 Routing That sounds complicated, isn't that where routers come in 314 00:14:36.519 --> 00:14:38.399 those boxes that connect us to the Internet. 315 00:14:38.480 --> 00:14:41.799 Yep, you got it. Routers are like traffic cops, sending 316 00:14:41.840 --> 00:14:45.080 those packets of data along the fastest route to their destination. 317 00:14:45.679 --> 00:14:51.000 And the book explains all those different routing protocols, RIPOSPF, BGP. 318 00:14:51.559 --> 00:14:54.039 They decide how routers talk to each other and share 319 00:14:54.080 --> 00:14:55.200 info about the network. 320 00:14:55.399 --> 00:14:58.840 Okay, so routing protocols are like the communication system for routers, 321 00:14:59.200 --> 00:15:01.159 making sure they have the the latest traffic in FOS 322 00:15:01.200 --> 00:15:03.440 so they can keep data moving smoothly. It's like a 323 00:15:03.480 --> 00:15:06.639 whole hidden world of communication going on behind the scenes. 324 00:15:06.759 --> 00:15:08.799 This is really cool. But before we go too deep 325 00:15:08.840 --> 00:15:10.919 into routing protocols, I want to touch on something else. 326 00:15:10.960 --> 00:15:14.840 The book mentions RFCs. What are those exactly? 327 00:15:15.080 --> 00:15:18.600 RFCs or request for comments are like the official rule 328 00:15:18.600 --> 00:15:21.919 books for the Internet. They describe all the protocols and standards. 329 00:15:22.240 --> 00:15:24.799 So if I want to understand how a specific protocol 330 00:15:24.919 --> 00:15:27.519 works down to the nitty gritty details, I could just 331 00:15:27.600 --> 00:15:28.879 check the RFC exactly. 332 00:15:28.919 --> 00:15:31.480 And the best part is RFCs are free online, so 333 00:15:31.600 --> 00:15:32.759 anyone can access them. 334 00:15:32.840 --> 00:15:35.240 Awesome. I'm gonna have to check out some RFCs, but 335 00:15:35.279 --> 00:15:38.039 for now, let's move on to security. Because what good 336 00:15:38.120 --> 00:15:40.080 is a network if it's not secure? 337 00:15:40.480 --> 00:15:43.679 You're absolutely right. Security is essential these days. The book 338 00:15:43.799 --> 00:15:46.840 really dives into this, starting with the basics like strong 339 00:15:46.919 --> 00:15:50.559 passwords and making sure you're regularly checking your system. It 340 00:15:50.600 --> 00:15:53.720 emphasizes that security isn't a one time thing. You have 341 00:15:53.759 --> 00:15:56.200 to constantly be vigilant and stay ahead of the game. 342 00:15:56.639 --> 00:16:00.200 Strong passwords, monitoring systems. Yeah, that's all well and good, 343 00:16:00.320 --> 00:16:02.840 but it seems like the threats are constantly evolving. How 344 00:16:02.840 --> 00:16:03.879 do we keep up well? 345 00:16:03.879 --> 00:16:06.399 The book gives you a whole bunch of tools and techniques, 346 00:16:06.639 --> 00:16:11.960 from access control mechanisms to intrusion detection systems, firewalls, and 347 00:16:12.039 --> 00:16:12.559 a lot more. 348 00:16:12.720 --> 00:16:16.279 Let's start with access control. That's about who's allowed to 349 00:16:16.320 --> 00:16:18.039 do what on this system, right right. 350 00:16:18.080 --> 00:16:21.159 The book covers all sorts of access control mechanisms, from 351 00:16:21.279 --> 00:16:26.320 basic file permissions to more advanced tools like PAM pluggable 352 00:16:26.360 --> 00:16:28.399 Authentication modules SAM. 353 00:16:28.440 --> 00:16:30.360 I'm not familiar with that. What makes it so special? 354 00:16:30.480 --> 00:16:34.279 PAM is really powerful. It lets you use different authentication methods, 355 00:16:34.480 --> 00:16:36.360 so you have a lot of flexibility in how you 356 00:16:36.480 --> 00:16:37.440 verify users. 357 00:16:37.639 --> 00:16:39.639 So, for example, could I use PAM to set up 358 00:16:39.639 --> 00:16:42.919 two factor authentication where users have to enter a code 359 00:16:42.919 --> 00:16:45.200 from their phone along with their password exactly. 360 00:16:45.480 --> 00:16:48.279 PAM gives you a ton of control over your authentication, 361 00:16:48.440 --> 00:16:51.240 so you can really tailor it to your specific needs. 362 00:16:51.559 --> 00:16:55.279 That's impressive. So PM helps control who gets in. But 363 00:16:55.360 --> 00:16:58.840 what about protecting the system from threats coming from outside? 364 00:16:59.320 --> 00:17:01.600 That's where fire walls come in, right. I was imagining 365 00:17:01.600 --> 00:17:04.559 them like a wall around your system, blocking any bad traffic. 366 00:17:04.759 --> 00:17:07.200 That's a pretty good way to picture it. Firewalls are 367 00:17:07.240 --> 00:17:09.960 like gatekeepers. They decide what traffic can come in and 368 00:17:10.000 --> 00:17:12.359 out of your network. The book goes through all the 369 00:17:12.400 --> 00:17:15.759 different kinds of firewalls, from simple packet filters to more 370 00:17:15.799 --> 00:17:17.599 advanced stateful firewalls. 371 00:17:17.759 --> 00:17:20.200 So a packet filter just looks at each packet of 372 00:17:20.279 --> 00:17:23.720 data and decides whether to allow it based on rules, 373 00:17:24.440 --> 00:17:27.359 but a stateful firewall keeps track of the whole conversation 374 00:17:27.920 --> 00:17:29.279 and makes smarter decisions. 375 00:17:29.359 --> 00:17:32.599 Exactly, and the book gives you step by step instructions 376 00:17:32.599 --> 00:17:36.039 for setting up firewalls on different systems using tools like 377 00:17:36.119 --> 00:17:39.400 iptables and PF. It even talks about techniques like GNAT 378 00:17:39.400 --> 00:17:41.519 Network Address Translation NATS. 379 00:17:41.599 --> 00:17:43.880 Yeah, isn't that how my router at home lets all 380 00:17:43.920 --> 00:17:45.920 my devices share a single public. 381 00:17:45.559 --> 00:17:48.960 IP address exactly. Nat is used all the time to 382 00:17:49.000 --> 00:17:51.559 save on those public IP addresses, and it also adds 383 00:17:51.599 --> 00:17:54.599 a layer of security by hiding your internal devices from 384 00:17:54.599 --> 00:17:55.440 the outside world. 385 00:17:55.720 --> 00:17:58.920 So firewalls are our first line of defense. But what 386 00:17:59.000 --> 00:18:02.440 about those threats that might slip through. That's where intrusion 387 00:18:02.480 --> 00:18:06.039 detection systems come in, right or IDSS you got it. 388 00:18:06.440 --> 00:18:09.279 IDs is are like alarm systems for your network. They're 389 00:18:09.319 --> 00:18:12.680 always watching the traffic and system activity, looking for anything 390 00:18:12.720 --> 00:18:13.799 suspicious that could be an. 391 00:18:13.680 --> 00:18:17.240 Attack, like security cameras, recording everything and alerting us if 392 00:18:17.279 --> 00:18:18.160 anything seems off. 393 00:18:18.480 --> 00:18:20.240 Yeah, that's a good way to think about it. They 394 00:18:20.240 --> 00:18:22.759 can log events, send out alerts, and even take action 395 00:18:22.880 --> 00:18:24.799 to block or stop attacks right away. 396 00:18:25.400 --> 00:18:29.519 Ideas sound like pretty powerful tools. But what about securing 397 00:18:29.599 --> 00:18:33.160 specific services like email? It seems like email is always 398 00:18:33.200 --> 00:18:35.440 vulnerable to spam and phishing attacks. 399 00:18:35.720 --> 00:18:38.960 Yeah, email security is super important, and the book dedicates 400 00:18:38.960 --> 00:18:41.440 a whole section to it. It covers everything from setting 401 00:18:41.480 --> 00:18:44.599