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Technology Tap
Technology Tap
A Plus+ Fundamentals: Network Language, Decoded Chapter 6
Ever wish the network would just explain itself? We walk through the real language of connectivity—how links come alive, how packets choose their paths, and how a few core ideas unlock routers, firewalls, addressing, and the exam questions that test them. It starts with the wire (and the air): DSL over copper, cable scaling with DOCSIS, fiber to an ONT at your home, and why fixed wireless, satellite, and 5G fill coverage gaps with very different tradeoffs in speed and latency. From there, we draw the line between moving traffic and governing it. Routers forward based on IP and subnets; firewalls enforce policy using IPs, protocols, and ports—think velvet rope, but for packets.
We bring the TCP/IP stack down to earth with a clean mental model of layers and encapsulation, then dig into IPv4 addressing, subnet masks, and private ranges that rely on NAT to share a single public IP. You’ll learn why static IPs belong on printers and servers, how DHCP’s DORA flow keeps clients online, and what APIPA is telling you when a lease fails. We also size up IPv6—128-bit addresses, hexadecimal notation, dual stack—and unpack the practical roadblocks that slow adoption despite the promise of massive address space.
Transport choices make or break performance, so we compare TCP’s three‑way handshake and delivery guarantees with UDP’s low-latency approach favored by streaming and gaming. We highlight the ports every tech should know—22, 53, 80, 443, 67/68, 21/20, 3389—because port literacy speeds troubleshooting. On identity and isolation, we translate DNS records (A, AAAA, CNAME, MX, TXT) into everyday use and show how VLANs reduce broadcast noise while VPNs protect data over untrusted networks. To cement it all, we run live quiz walkthroughs and model how to spot keywords, eliminate distractors, and reason under time pressure—skills you can carry straight into the CompTIA A+ and beyond.
If this helped you think more clearly about networks, follow the show, leave a rating, and share it with a friend who’s studying. Got a topic you want us to deep-dive next—DHCP, DNS, or VLANs? Drop a note and subscribe so you don’t miss the next breakdown.
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Art By Sarah/Desmond
Music by Joakim Karud
Little chacha Productions
Juan Rodriguez can be reached at
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And welcome to Technology Tap. I'm Professor J-Rodd. In this episode, The Language of Networks, I just think, Connections, and Communication. Let's tap in the world. Welcome back to Technology Tab, where we keep tapping into technology. I'm Professor J. Rod, and today we're decoding the language that keeps every network alive: addressing and connectivity. Whenever you're installing a router at home or supporting the hundreds of users in an enterprise, the same fundamentals apply. IP addressing, ports, DACPs, DNS, VPNs, and VLAN. This episode follows the module for the Compia core exam, and by the end, you'll see how every packet knows where it's going and how it gets there. Internet connection types from mobile from modems to fiber. Every internet session begins with a modem, the bridge between your network and your internet service provider. DSL, digital subscriber line, runs over regular phone lines. Asymmetric DSL is faster download. Symmetric DSLs keep speed equals for businesses that upload data consistently. Cable modems. That's why upgrading to DOS Sys 3.1 can bump you from 300 megabits per second to 1 gig. Fiber to the premise. Pure glass from the provider straight to your home or business, terminating at an ONT, optical network terminal. Wireless and cellular. Imagine a rural repair shop too far for cable or fiber. It might use a fixed wireless through a wireless ISP or WISP. Satellite, like the Starlink LEO LEO constellation, offer lower latency alternative to geostationary orbit. And on the go, cellular networks have revolved from 3G CDM to 5G with massive MIMO enabling speeds once reserved for wirelines. Routers and firewalls. Your router makes IP-based forwarding decisions determining which interface each packet uses. Meanwhile, a firewall enforces rules known as access controllers. Filtering traffic by IP, Mac, protocol, or port. Think of it as a bouncer checking IDs before anybody enters the network club. Here's an example. A rule that says allow TCP 443 from any internal web server permits encrypted HTTPS traffic but blocks everything else. The four layer model. The TCP IP is a suite of protocols with layers. One, link layer, frames traveling using MAC address. 2. Internet layer, routing packets via IP address. 3. And 4. The application layer protocols like HTTP and DNS. This TCPIP 4 layer model is similar to the OSI model. The OSI model, as you know, has seven layers. The TCPIP model has only four layers. Each layer wraps the data in its own header, like stacking envelopes inside envelopes. IPv4 masking and addressing. An IPv4 address is 32 bits long. Four octaves, eight bytes each. Four times eight equals 32. So for example, 192.168.1.25. Each octave, so for example, 192 will be considered an octave, has eight bits. 168 has eight bits. One has eight bits. What do you get the number from? The number, and I'll have to do a deep dive, a little bit of a deep dive on this. The number depends on how many bits you turned on. Which bits you turn on. So there's certain bits, you know, there's eight, the eight bits are 128.68, 32, 16, 842.1. And so 25, you would have 16 on, 8 on, and 1 on. So that's the example. But I'll do a little bit of a deep dive on another episode about IP addressing. It cannot be done. It has to be its own separate topic. Uh the setnet mask device network ID and host ID. Example 255.255.255.0 means the first three octaves identify the network. Public versus private. Private range uses inside lens. Use the class A is 10.0.0.0. For class B, the range is 172.16.0.0 to 172.31.255.255. For class C is 192.192.168.0.0. The router performs NAT or network address translation, mapping private address to public ones. That's a hundredths of device, share one internet IP. Again, this is another topic that's going to have its own segment because it's just too, you know, I can do 23 minutes just on public-private addressing. So that'll be its own separate thing. So example, your phone 192.168.1.50 says request. The router translates it to 7575.32.18.7 on the internet. Uh the reply returns and is DNAT back to you. Static, dynamic, and uh PIPA. Static IP, you manually enter it, useful for printers and servers. Usually you want to use static IP for uh devices that are never going to change, that you don't want the IP never to change. So you know, your printers, your servers, your routers, maybe a managed switch, right? Those are devices that you never want to change. So it's fine. Uh DHCP automates address assignments through Dora. Discover, offer, request, acknowledge. These are for like your workstations, right? Things that you don't care if the IP address changes. You know, pretty much your workstations, you don't really care if the IP changes. There's no you don't need to hard code your workstations. And a PIPA is when the address starts with 169.254, appears when DHCP fails, Windows way to stay local when disconnected. IPv6, which is going to be the new standard of internet addressing, when is that gonna happen? Who knows? I've been hearing about IPv6 for the last 10 to 15 years. Yeah, I don't know when it's coming. Coming soon, it's like forever. So, what's the biggest obstacle? I'm pretty I'm pretty sure it's money. And why? You know, why at this point, if everything's working, why change it? And then in order to change it, you know, it's gonna cost it's gonna cost money, it's gonna cost time. You gotta get these texts to make all these changes. That's that's gonna cost money. But anyway, IPv6 uses 128 bits, hexadecimal notation, and colons. So an IP address can be let's say 2001 0 dB858300, colon 8A2E, 0370, 7334. Dual stacking lets Ipv4 and IPv6 run side by side. Organizations adopt IPv6 for its nearly limited address space. I don't know anyone that is actually using it, but again, it's coming soon. You have your protocols and ports. TCP and UDP uses ports from zero to sixty five thousand three hundred to differentiate service. TCP is connection-oriented, which is reliable. UDP is connectionless, faster, but no guarantees. UDP is like Netflix, YouTube, right? A lot of data going back, you know, send me the data, send me the data, send me the data, right? TCP is like email, logging into a website, right? So some well-known ports that we have out there that you know you may need to learn. FTP file transfer port codes uses port 2021 and is TCP based. SSH, port number 22, TCP based, DNS 53, it's UDP and TCP based. HTTP is 80 port, uh port 80 and it's TCP based. HTTPS uh port numbers 443 and it's TCP based, DHCP, port numbers 67 and 68, and it's UDP based. And RDP remote desktop is 3389 TCP-based. When you're visiting a website using HTTPS, your browser initiates a three-way handshake: sync, sync act, and act to establish a reliable connection. Sync means synchronization and act means acknowledgement. So it's synchronization, synchronization, acknowledgement, and then acknowledgement. A real world example is a game streaming platform may use UDP for real-time videos because dropping a few frames is better than delaying the stream. Just like Netflix, right? Dropping a few flame uh frames in Netflix is better than delaying the film. So and they use UDP. Network configuration concepts, DHCP functions. A DHCP server manages scope, leases, and reservations. If you reserve a MAC address, that device always gets the same IP. Perfect for printers or security cameras. DNS, the phone book of the internet. The domain name system translates names into IPs. When you type, you know, www.google.com, right? It resolves to something like 8.8.8.8. A record type should know A through quadruple A is IPv4, IPv6, C name is your alias, MX is always for mail server, and that's a clue for the Camtia test, right? If you see a question and the question that they ask you has the word MX in it, just look for mail server or email. It's usually that's usually what the answer is. And TXT or text uh verification or SPF data. Example DNS lookup follows a chain root server, right? Then the top level domain, and then the authoritative server, and then your answer VLANs and VPNs. VLAN or virtual LAN segment a switch into isolated uh broadcast domains. For instance, separating finance traffic from students in a capitalist network, and then your virtual private network creates an encrypted tunnel over public Wi-Fi. Example, when you connect your college VPN, all traffic to internal servers is secure, even if you're in a coffee shop. Again, this some of this stuff we would have to expand on it. It's just you know, to do these short snippets that I'm trying to do, especially with the questions at the end and the allotted 23 minutes, 24 minute time that I want to get to. It only gives us time for these snippets. But I will do like a deep, deep dive into DHCP, DNS, VLANs. I'm you know, that needs that deserves you know, a public-private address, all that stuff deserves huge deep dives, separate podcasts on its own, separate episodes. I'm following the the like what Certmaster gives you, which honestly doesn't really give you a lot as far as the PowerPoints is concerned, and that's what I'm using just to just for quick snippets. But to be fair, I have to, if I'm gonna, you know, be a good instructor or a good teacher, I have to give you the full definition of what DHCP does. And I have a whole thing, I you know, if my if you take my class and I've gone over DHCP, you know how I do it. I do a whole scenario and stuff, and but it deserves its own episode. You know, a couple of these things, now that we're getting into the meat of A plus, it deserves its own, its own uh episode. Some of these stuff is just too big to cover in snippets. So all right, let's do the questions. All right, so if you're new to this, the way I do it is I ask the question, I read the choices, and then I do it again. I give you five seconds and you try to guess if the answer is right. Question one Which internet connection typically uses an optical network terminal at the customer's presence? A DSL, B, cable, C fiber to the premise, or D satellite. Again, which quet which internet connection type typically uses the optical network terminal at the customer premise? A D DSL B cable C fiber to the premise or D satellite. I'll give you five seconds to think about it. Five, four, three, two, one. And the answer is C, of course, fiber to the premise. Connections terminate at an ONT that converts optical signals into internet for use inside the building. And ironically enough, ladies and gentlemen, if you took my classes years back, I would always say there was, you know, there's no way they would put fiber in your house. But now they do. They actually do put fiber in your house, which I find amazing that they do that because fiber, if you know anything about fiber, it's very, very delicate. I have a Verizon 2G, and there's actually a fit of uh fiber cable inside my house, which I never thought they would do. I would never throw they would do, but it's there, so I just gotta be careful not to uh break it. All right, question two addressing. Which IPv4 address range is reserved for automatic private IP addressing or a PIPA? A 10.0.0.0 slash eight, b 169.254.0.0 slash 16, C 172.16.0.0 slash 12 or D what 192.168.0.0 slash 16. I'll read it again. Which IPv4 address range is reserved for automatic private IP addressing or a PIPA. A 10.0.0.0 slash eight b 169.254.0.0 slash 16 C 172.16.0.0 slash 12 or D 192.168.0.0 slash 16. I give you five seconds to think about it. 54321 and the answer is B 169.254.0.0 slash 16. Windows assigns a PPR address in the 169.254.0.0 to 169.254.255255 range when no DHCP server is available. See, this is what I mean. Like that is something that I need to explain more. Right? So maybe the next episode of A, I will go into a whole deep dive of what DHCP is, how it works, you know, fully, fully express explain it, break it down. I think I do a really good job of breaking it down for my students for DHCP, you know, using a scenario that everybody's familiar with. And then that way they, you know, you can they you really understand how you know things work, right? Because we're getting into the granular level of things, and you really need to know how these things work, especially if you're gonna take the A plus class. So, and I'm gonna do a lot more deep dives on the on the A plus. All right, protocols and ports. A network administrator wants to secure remote logins by encrypt by encrypting traffic. Which protocol and port should they use? A telnet port number 23, B SSH, port number 22, C HTTP, port number 80, D FTP port number 21. Again, I'll read it again. A network administrator wants to secure remote logins by encrypting traffic. Which protocols and ports should they use? A telnet slash 23 or port number 23, SSH port number 22, HTTP port number 80, or D FTP port number 21. So this is uh here's how you would tackle this question, and this is part of the CAMTIA way, right? If you look at the question, if you listen to the question, because you can't look at it, if you listen to the question, you will see that it says a network administrator wants to secure just that word secure, that's the clue in the question, secure. So out of all of these, which one could you eliminate right away? Well, HCTP is not secure, so that's our right telnet. If you know anything about telnet, that's not secure. That's out, right? And then you're left with SSH and FTP, and then wants to secure remote logins. The answer is B, SSH. Right? SSH encrypts remote terminal sessions, unlike telnet, which sends data in plain text. So there's also like a about, I don't know, 20, 22 of these ports that you need to know for the exam. I will also do a deep dive on that. It's important that you know these, and once you know them, it scaffolds, right? So this is the good thing about CompTIA, and this is the good thing about taking a CompTIA exam at A plus, at the A plus level, and not skipping to Security Plus like right away, right? There's some people who who right away they don't they don't do anything, they don't they don't never worked in in PC before. Maybe they fixed their friend's PC, right? They're that one guy, but they've never really, really worked in IT. So they want to jump all the way to security, and the and that that test is really hard. I mean, there's people who've done it, and I've known two people who have done it. But both former students, but most people can't. I mean, you really, really, really gotta be dedicated if you want to take a security plus course or study on your own. I know one young lady who studied on her own and she passed, and then one took a class with me and he passed. But it's not it's not an easy exam, and to just try to jump in the line is kind of difficult. But if you start at A1, uh A, it scaffolds. So you go to network plus, like 50% of network plus is in A, and like 30% of security plus isn't A. You know, you know, so you know you learn the foundation, and it's better to start at A. I don't know why people want to jump the line, but that you know, that's them. All right, last question: network configuration. What is the primary purpose of virtual LAN or VLAN on a managed switch? A to provide wireless coverage in large area, b to segment network traffic for performance and security, C to encrypt tunnels over the internet, or D to assign dynamic IP address to clients. I'll read it again. What is the primary purpose of a virtual LAN or VLAN on a managed switch? A to provide wireless coverage in large areas, b to segment network traffic for performance and security, C to create encrypted tunnels over the internet, or D to assign dynamic IP address to clients. Now, you have a before you tackle this question, if you listen to it, there's a couple of clues here. One is manage switch, right? So anything that has to do with IP addresses, it's out because switch does not manage IP address. So D is out to assign dynamic IP address to clients, that's out, right? So you left with to provide wireless coverage in large areas to segment network traffic to for performance and security and to encrypt network tunnels over the internet. Nothing to do with the internet, a switch does not do anything with the internet, C is out. So you're left with A and B, and the answer is B. VLANs divide a switch into multiple logical networks, isolating traffic and reducing broadcast domain for better performance and security. That's how you tackle A plus exam. Just like the way I did it. Just look at the question. Not every question is going to have a clue because a lot of them is gonna say, hey, what's the port number for Telnet? Right? So that there's no clue in that. Either you know it or you don't know it. But some have clues. And you look at the clues from just reading the clue, reading the question, you gotta dissect it, right? That's what I call it. You gotta dissect the question. And but you only got a minute to do it. You don't have a lot of time, you gotta like average like a minute of question. So I always tell my students, go through the exam first, the first time, answer the questions that you can answer, right? If you answer the questions that you think you can get it right, answer those and then go back and then answer the rest, and then take your time because you can answer a question that you know like 10-15 seconds. So then that you know that will help you 100%. Alright, let's wrap this up, guys. From DSL to DNS, from IPv6 to VPNs, you now understand how iDressing keeps the internet organized. That Comp Tia test doesn't just test your memory, it tests how you think through connectivity problems. I'm Professor J. Rod, and I just want to remind you stay curious, stay secure, and always keep tapping into technology. This has been a presentation of Little Cha Cha Productions, art by Sarah, music by Joe Kim. We're now part of the Pod Match Network. You can follow me at TikTok at ProfessorJrod at J R O D. Or you can email me at professorjrodjr-od at gmail.com.