Networking Tutorial: Subnetting Theory and Application

[@mrwilly5138]

15:08 The number of addresses for /25 mask would be 128 not 64 and usable host address will become 126. (removing network and broadcast address). edit: 22:17 Alright here the calculations looks good. 😅

[@PE4Doers]

You are absolutely correct. I will take a second look and update the content for Post a 'pinned' comment.

[@Pro1er]

That was really well done. It's a shame that there are so few views after all of the work and all of the thought you put into this presentation. Thank you.

[@PE4Doers]

Thanks. I was working on that presentation for a while. I suppose there aren't too many people interested in hearing a college lesson on Networks. I have also come to learn that very few people want to listen to highly technical material in a video that exceeds about 20-mins.

[@Pro1er]

@@PE4Doers I can tell you put some effort into the lesson. There are probably a lot of people who would be interested in this video but KZbin algorithms can be sketchy. I've enjoyed some of your other videos as well, you have a good teaching style and you keep it clean. Also, you answers questions which is greatly appreciated. Thanks again.

[@PE4Doers]

@@Pro1er Thanks again. I truly appreciate you taking the time to watch 🙂

[@PE4Doers]

Hi everyone. I probably should have made this point more distinct in the video (during my 'Real World' example), however I wanted to emphasize that most network administrators today do not have to 'squeeze' an address space to the degree shown in most CCNA prep courses (and probably reflected in the test). This is due to the extensive use of the non-routable 'Private' address ranges (9:35), that allows an organization to choose any of those address ranges for all their internal device addresses. If you have any specific questions, please leave them as comments to this video. Take care networking 🙂

[@incognito8168]

Thanks to you sir, i appreciate this topic already. During my college days as an IT student, i used to hate our Networking subject, such as subnetting etc. Perhaps my college instructor didn't told us the significance of such subject. I'm now starting re-learn those things. Truly appreciated.

[@PE4Doers]

Thanks so much for this great comment. I'm glad you are able to get something out of it 🙂

[@nicolasbourbaki8896]

The best tutorial I have seen in regarding Networking👍

[@PE4Doers]

Thanks for the nice comment.

[@woodysranch2690]

I would love to see more of this. It will take some study to understand the concepts you present here unlike maybe some of your viewers who seem to already have a networking background, but it serves as a catalyst to dive deeper. I am particularly interesting in a discussion on how to design a small network in your home - such as the tree's you displayed at the beginning of the video but on a smaller scale.

[@PE4Doers]

OK, I was thinking of something more for the beginner/ small network. I was planning on talking about that when I show how to configure my new Router, but maybe I should put out simpler primmer befor doing that.

[@LidZLife]

Thank You for the video and your time. This was so very helpful. Absolutely a bang on job! Cheers!

[@PE4Doers]

Thanks you Sir. I truly appreciate this great comment.

[@gazam9571]

Thanks for this video. It has definitely improved my knowledge.👍

[@PE4Doers]

You are very welcome. Are there any other Networking concepts you would like me create videos about?

[@txfalkon2882]

well explained sir this very informative. It deserved a SUB. which I gave. thanks for time put in. I will recommend more people to come check out you videos. This is the field I am working in so once in a while having fresh eyes on these ideas is great

[@PE4Doers]

Thank you very much for your great comment and observations.

[@kodjokyei]

Really helpful. Thank you sir

[@PE4Doers]

You are quite welcome. Thank you for watching and commenting 🙂

[@areloandraska9897]

Very good video, very informative, great work

[@PE4Doers]

Thanks you - I really appreciate your nice comment 🙂

[@KenPryor]

This was so helpful! Thank you!

[@PE4Doers]

You are very welcome 🙂

[@nian60]

Great video. Thanks.

[@PE4Doers]

Thank you for the nice comment 🙂

[@mazchen]

Thank you for the time and effort you've put into this! One question: when you designed that larger network at around 30:00, what is the reason tha level A with lowest number of participants gets the biggest range?

[@PE4Doers]

Just in-case it needs to be expanded with another subordinate level. It's IP address are meant to by other networks - sort of like the Universe having Galaxies, then the Galaxies having Solar Systems.

[@tomtom-r8q]

thank you ...!

[@PE4Doers]

you're welcome 🙂

[@1d9d5k6]

I never thought I would need more than 254 addresses. However, with the implementation of IOT devices, the time has come to change. I am currently using two separate addresses (one for IOT and the other for general use). Now because of your information, switching to /23 might make more sense for future proofing my network and using VLANS for segregation. What are your thoughts? BTW, great video and fantastic teaching.

[@PE4Doers]

I though 'excatly' the way you did until I realized I was down to just 7 free IP's. I forget if I mentioned it in this video (possible in the video I made about DHCP), but the router will start to purge the lease used addresses from its table for reuse. Believe it or not, that is a 'hack' into small network if you know that's taking place.

[@sulaimonadekoya2682]

@PE4Doers... First of all thanks so much for this video. Please sir can you do a video when someone have two ISP.

[@PE4Doers]

At this time I do not have my network configured that way. Maybe in a couple of years as I move toward Pro-Sumer network routing (such as a Ubiquity router). To do that properly the router (or an internal switch needs to be able integrate and prioritize the two Internet connections, such as going to the one with highest throughput at a particular time.

[@kiannadavis7974]

Hi, so how would you implement the block size per your example of the charitable facility? For example, the /21 network had a block size of 8.

[@PE4Doers]

Can you explain a bit more what you mean by 'Block Size'?

[@kiannadavis7974]

The block size is the increment you will be counting in the interesting octet for calculating new IP ranges beyond a classful subnet mask. The block size is said to be calculated by subtracting the subnet mask VALUE in the interesting octet from 256. This will result in the increments of how your subnets should be created. This information is found in the network+ exam book

[@PE4Doers]

@@kiannadavis7974 It sound like you are referring to the segments. The number that is always a power of 2 based on a particular sub netted section. In this example, it is using a few different segment sizes. are you wondering about each one? If you can imagine a pie (that you would slice up to eat), then you can initially cut it in half (to feed the gluten at the table), then you can decide to cut the other half into quarters for the standard slice size. However if you have a couple of children at the table, you could cut one of those quarters into eights for them, unless you want to a problem like my wife usually, and want only a sliver which, when you talk about sub-netting< you can break down to just two addresses if you want.

[@Kiannadavis]

@@PE4Doers Hi Dr. Thank you for this information. I understand what you are referring to, however, when I refer to the block size I am referring to the ranges of ip address between the start of one subnet to the next subnet. Of course, each subnet having a network ip and broadcast IP. I was confused on whether or not the information carried in the book was truthful

[@PE4Doers]

@@Kiannadavis Oh, thanks for the clarification. With that, the 'block size' for /27 is 2 to the 4th power, which equals 16, then minus 2, which ends as 14. If I said it was 8 (something I have to re-watch my video to see) then I was off by a few IP addresses. The basic mathematical method is to subtract what is to the right of the slash, from 32 then use that as the exponent of 2, then subtract 2 from the total.

[@woodysranch2690]

In another video about setting up XigmaNAS you mentioned Active Directory. I find this subject very confusing. You might consider some sort of tutorial about Active Directory dumbing it down for us meer mortals.

[@PE4Doers]

I did make one of those a while ago, but I will look at it again to see if it is something I can simplify ever more.

[@woodysranch2690]

@@PE4Doers My apologies. I should have reviewed your other videos. I didnt mean to "make work" for you. What is the title of the video you refer to and I will watch it?

[@PE4Doers]

Mr. Ranch, no problem at all. It is more than a confusing concept. The last video I made on the subject was sort of an epilogue to my server build. The link to that video is: kzbin.info/www/bejne/f6nKgmWsiJl5pNk That video is approaching 2-years old, and if you get a chance to watch it, please let me know if it makes sense and is simplified enough enough.

[@JD-sn1lr]

So in the movies, when some hacker has installed malware to a computer, if the computer user discovers the attack, could they modify the net mask to CIDR /32 to prevent the user's computer from communicating back to the hacker?

[@PE4Doers]

I think it would be more important to prevent the attack to start with. A counter attack could actually become illegal, since the attacker could be inside a corporate or government system network and launching the attack from that satellite location (sort of like how the US hopped from island to island to get closer to Japan and counter-attack it during WW-II - there were some that believe the US was then the aggressor). You could then be considered the attacker on that network.

[@BobFrTube]

Why all this brittle complexity rather than using DHCP for assigning addresses?

[@PE4Doers]

The design is meant to properly segment several departments of a small/medium sized organization. DHCP can be used within one of the network 'leafs', but doing so beyond a certain number of client systems would lead to network congestion and possible failure if the one primary DHCP server were to fail. Also, Server can be made more secure and easier to administer by having Static address rather than those delved out by DHCP. In a future video I will show how using Virtual Networks (V-LANS) can provide even better security and a further in high traffic network segments.

[@BobFrTube]

@@PE4Doers That's like saying you should program in assembler to have more control or use disc addresses rather than GUID to make databases more efficient. It presumes a very static world in which no devices are mobile. What happens when you have a phone or laptop that has switched sites? You also seem to way overestimate the cost of using DHCP. Just because a long time ago one had to manage /etc/hosts doesn't mean it's a good idea. I can't imagine trying to manage my hundreds of devices manually. And for those without a full-time IT staff, it's dangerous. As to DHCP failure, you don't suddenly lose your addresses. If worried, use a long TTL. The key point is the manage bindings rather than wiring things in. If anything, to manage my hundreds of endpoints, I want more from DHCP, not less.