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Easiest best explanation on subnetting

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Hey all,

So I'm going back to school for IT in the Fall. I've been there before and I love Systems design for IT. I'm a troubleshooter and enjoy it all. However I had an extremely negative mindset when I was there. I had a lot of mixed decisions and bad habits..

/end story

I'm wondering if anyone could help me with some easy explanation in video or pdf (or both) on subnetting. I am told everyone uses calculators, but I must learn this as it's clearly a barrier in the past.

I am grateful for any help I receive. Please keep it current. Trust me I know how pathetic of a question this seems. <insert let me google that for you meme>

Thanks!
Mark7805
 

Kursah

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Do the work and put in the time on subnetting and CIDR, you'll thank yourself later. Really I see many common subnet ranges, /16, /22, /23, /24, /29, /30 and /32. To visualize how that correlates with available addresses, check this link for a cheat sheet that can be used as a reference for class-C subnets and to check your work. There's a method to the madness and a pattern but it isn't easy to remember unless you work with it often. It also depends on if you're focus will be IPv4 (likely) or IPv6 (probably later on) for how addresses are managed. But assuming you'll primarily be focusing on IPv4, get familiar with class A, B and C LAN ranges, how to ID private vs. public IP scopes, understand the terms and functions of Subnet, Supernet, Subnet Mask, Supernet and APIPA.

Good for you for getting back into it, but I'll be the first to admit there is no "easy" way to get back into subnetting. You want to learn it, then build a lab at home and start screwing around. Are you going through a CCNA course? If so, you can use the Cisco PacketTracer software to create and provision a network and do different subnets.

I try to not use calculators as often unless we're in a time critical situation and my brain is failing me, but I worked extra hard in the CCNA 2nd semester course which in my version of the course was heavily focused on CIDR for half of it. The workbooks and hours I spent have really helped me to understand and lay out nice clean networks.

If you take any future certifications, Network +, CCNA, MCSA, etc...you'll need to understand subnetting and work it out in your head or using a scratch sheet of paper, so knowing the pattern and a way to remember it is critical.

I also dig Eli the Computer Guy, so here's his video on TCP/IP and subnet.

Don't feel bad asking for help, part of going to college is learning how to find help outside of the classroom. Learning how to use search resources, how to ask for help, etc. If you have trouble searching for help, I suggest taking an elective course on that topic, most colleges provide good courses for that very thing. We're here to help, and hopefully show you a path to helping yourself better as well!

:toast:
 
Joined
Feb 15, 2008
Messages
213 (0.04/day)
System Name Shark's Build
Processor AMD Ryzen 7 5700X 3.4 GHz
Motherboard Gigabyte B450 I AORUS PRO
Cooling Noctua NH-C14 heatsink core with swapped Phanteks PH-F140HP PWM
Memory G.SKILL Aegis (2 * 8GB) DDR4-3000
Video Card(s) GeForce RTX 3060Ti 8GB
Display(s) Tri-Monitor setup 1x144hz 2x60hz
Case Corsair Obsidian 250D Mini ITX
Audio Device(s) On-Board
Power Supply EVGA Supernova NEX750B 750W ATX Power Supply 80+ Bronze
Do the work and put in the time on subnetting and CIDR, you'll thank yourself later. Really I see many common subnet ranges, /16, /22, /23, /24, /29, /30 and /32. To visualize how that correlates with available addresses, check this link for a cheat sheet that can be used as a reference for class-C subnets and to check your work. There's a method to the madness and a pattern but it isn't easy to remember unless you work with it often. It also depends on if you're focus will be IPv4 (likely) or IPv6 (probably later on) for how addresses are managed. But assuming you'll primarily be focusing on IPv4, get familiar with class A, B and C LAN ranges, how to ID private vs. public IP scopes, understand the terms and functions of Subnet, Supernet, Subnet Mask, Supernet and APIPA.

Good for you for getting back into it, but I'll be the first to admit there is no "easy" way to get back into subnetting. You want to learn it, then build a lab at home and start screwing around. Are you going through a CCNA course? If so, you can use the Cisco PacketTracer software to create and provision a network and do different subnets.

I try to not use calculators as often unless we're in a time critical situation and my brain is failing me, but I worked extra hard in the CCNA 2nd semester course which in my version of the course was heavily focused on CIDR for half of it. The workbooks and hours I spent have really helped me to understand and lay out nice clean networks.

If you take any future certifications, Network +, CCNA, MCSA, etc...you'll need to understand subnetting and work it out in your head or using a scratch sheet of paper, so knowing the pattern and a way to remember it is critical.

I also dig Eli the Computer Guy, so here's his video on TCP/IP and subnet.

Don't feel bad asking for help, part of going to college is learning how to find help outside of the classroom. Learning how to use search resources, how to ask for help, etc. If you have trouble searching for help, I suggest taking an elective course on that topic, most colleges provide good courses for that very thing. We're here to help, and hopefully show you a path to helping yourself better as well!

:toast:

No negative mindset now :p A lot of it was personal health crap I was dealing with.

~

It really is one of those topics that has to be nailed down. The program structure that I'm taking is a scramble of certifications that should go well together, like CCNA and CompTIA(I think) along with an inhouse curriculum.

I just know that now is almost summer time, I'm finding myself with downtime, and I want to be prepared to dive in with a locked-on focus. Subnetting always was something I struggled with so I want to primarily set my target on that for now.

I really appreciate all the info and links I think these will be a great start :)
 

Kursah

Super Moderator
Staff member
Joined
Oct 15, 2006
Messages
14,666 (2.30/day)
Location
Missoula, MT, USA
System Name Kursah's Gaming Rig 2018 (2022 Upgrade) - Ryzen+ Edition | Gaming Laptop (Lenovo Legion 5i Pro 2022)
Processor R7 5800X @ Stock | i7 12700H @ Stock
Motherboard Asus ROG Strix X370-F Gaming BIOS 6203| Legion 5i Pro NM-E231
Cooling Noctua NH-U14S Push-Pull + NT-H1 | Stock Cooling
Memory TEAMGROUP T-Force Vulcan Z 32GB (2x16) DDR4 4000 @ 3600 18-20-20-42 1.35v | 32GB DDR5 4800 (2x16)
Video Card(s) Palit GeForce RTX 4070 JetStream 12GB | CPU-based Intel Iris XE + RTX 3070 8GB 150W
Storage 4TB SP UD90 NVME, 960GB SATA SSD, 2TB HDD | 1TB Samsung OEM NVME SSD + 4TB Crucial P3 Plus NVME SSD
Display(s) Acer 28" 4K VG280K x2 | 16" 2560x1600 built-in
Case Corsair 600C - Stock Fans on Low | Stock Metal/Plastic
Audio Device(s) Aune T1 mk1 > AKG K553 Pro + JVC HA-RX 700 (Equalizer APO + PeaceUI) | Bluetooth Earbuds (BX29)
Power Supply EVGA 750G2 Modular + APC Back-UPS Pro 1500 | 300W OEM (heavy use) or Lenovo Legion C135W GAN (light)
Mouse Logitech G502 | Logitech M330
Keyboard HyperX Alloy Core RGB | Built in Keyboard (Lenovo laptop KB FTW)
Software Windows 11 Pro x64 | Windows 11 Home x64
That's how my curriculum was too. CCNA and CompTIA. I didn't pursue my CCNA certification though. I did earn my A+ and Net+ through the course, and for those courses we used TestOut's PC Pro and Network Pro curriculums and gained those certifications as well. Hopefully you can get as many certs as you can possibly stand to earn through school, abuse those voucher discounts wherever possible.

Microsoft also offers discounts to students, paying close to $90/exam vs $165 is a HUGE difference for a broke family guy like myself. :D

Networking isn't easy to figure out or easy to stay on top of, and subnetting is really just a part of it...but it is important. VLANs are also very important as well. If you can muster up a spare PC or two, create a virtual lab, and get an old cheap Cisco, HP or Netgear Layer-3 switch or two...you could do A LOT of good for yourself.

I created a virtual lab on my school laptop, which was a Dell 3540 with a low powered i5 and 8GB DDR3. If you have Windows 8 or 10, install Hyper-V, learn how to create, manage and network virtual machines. The place I work for happens to be a Microsoft shop so it worked out in my benefit to go that way.

Just keep your mind open and always be willing to learn something new and relearn something you forget, you'll do just fine. Good luck with your ventures, hopefully you'll keep us posted. :toast:
 
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