Fastest 10-Seconds SUBNETTING Trick for CCNA Exam - Find any subnet within 10 seconds guaranteed

how's it going guys my name is Albert Roy and today I am going to teach you how to do subnetting in just under 10 seconds and when I say under 10 seconds it is implied that you have the basic understanding of what an ipv4 addresses and the use of various subnet masks now mind you this is not an introduction to subletting but rather a shortcut to the traditional method of submitting in this shortcut method we will use something called the subnetting chart which is not that difficult to make once you get the pattern and only takes you a minute or two to make the chart the advantage of this subnetting chart is that we can skip the tedious process of the binary conversions involved and help us save time so without further ado let's get started alright so what you have in front of you is the ipv4 subnetting chart and as you can see it is divided into two parts so first of all deal with the left-hand side which will help us to determine which octet of one of these four we have to work with of this IP address all right so let's take this IP address for example be given a slash notation subnet mask is the 29 slash 29 so immediately we will look into the chart and we'll figure out slash 29 is right over here so this immediately tells us that we have to deal with the fourth octet of the IP address which is 176 now they'll have to figure out if you want you can figure out the the decimal mask number which is nothing but 248 so our equivalent decimal subnet mask would be 255 dot 255 dot 255 dot to 48 that is right and we also have the increment which is the size or the range of the subnet so in this particular case 29 we get an increment of a right so this means that the size of the subnet is nothing but 8 now we look at the right side of the table and we have the multiples of 8 so we can just quickly go through is there is 176 understable yeah there we go so so once you see 176 right over there this immediately tells us that this particular IP address is nothing but the network address of that particular subnet quite quite confusing all right let's take one look at another example that I have here for you let's look at this beautiful example so which subnet does the host 192 dot 168 now 1 0 3 a 1 5 1 belong alright so here first of all we'll look at the given subnet mask always whenever our subnetting problem is given look at the mask first which octet do you see that is not a 255 on a 0 it is obviously the octet for 128 so now we know that we have to deal with the fourth octet of this IP address so remember 128 will quickly go to the subheading chart and figure out the increment right so the mask was 128 and immediately we find that the increment or the size of the subnet is nothing but 128 now we come to the multiples of 8 chart and we'll try to figure out so the subnet range is from 0 2 all the way to 127 so this is your entire subnet this is of the number 1 and we have subnet number 2 so the first subnet range is from 0 to 127 and then we have 128 to 255 so there we go and we'll just jump back to the question that we have ok we figured out there is there are two subjects but which subnet is it that we don't know yet so they'll go to the question and like I said we have to deal with the 4th objet and this number right over here is 151 so we move to the subheading chart so which subnet this or this contains 151 nope yep it should be there somewhere yep 151 so definitely this is the subnet that we are looking for so we have the answer the subnet address would be nothing but 128 so it is good to the question there we go that is the network address one eye to the 168 a 1 0 3 to 128 now let us take yet another example to clearly understand how the chart is being used what is the first valid host on the subnet that the node 172 dot 17 to 120 4.40 1/19 belong so as always if we look at the slash notation of the 7 mask first which is slash 19 so let's head over to our subnet subheading chart and figure out which octet it belongs to or which octet is the interesting octet that we have to deal with 19 lies in the third octave which means that our subnet mask is nothing but 255.255.255.0 right and this also gives us the increment of 32 which means that the subnet that we are going to find has a size of 32 right so we head over to the multiples of 8 chart and we have to figure out the size now I have bolded these numbers which is the multiples of 16 so the given increment is 32 so we can figure out that the first subnet would be 0 to 31 the second subject would be 32 to 63 then the third subnet 64 to 95 the 96 to 127 and so on and so forth so we can see that there are totally eight divisions right so all these now which we will head over will head back to the question and we know that we have to deal with the third octet so let's find out what number is an ether doctor it's clearly 124 right so we have to try and find out which subnet does 124 lie in that multiples of 8 1 2002 32 nope 124 cannot lie there 32 to 63 note 64 to 95 nope 96 to 127 yes definitely 124 is greater than 96 but less than 127 so yes so obviously 96 should be the network address so let's head back to the question these subnet range is 32 and the subnet I'm sorry and the network address is 172 dot 17 296 dot 0 now we can also figure out the various other addresses such as the first host address last host address and even the broadcast address so we can just head back with a subheading chart and we figured that this is the subnet that we have to work with so 96 was the subnet ID then obviously 127 is the broadcast address right so 127 dot 255 the last octet will obviously have the maximum possible value which is 255 because that has nothing to do with subnetting as such and then the first host and the last host is pretty much easy so first source is nothing but 1 plus the network address which is 96.1 and the and similarly the last host address is nothing but the broadcast address minus 1 so in this case it will be 127 . 254 so there we go guys we have just done subnetting using nothing but the subnetting chart that we have over here and trust me it's not that difficult it might seem slightly you know overwhelming at first but then once you get the hang of using this particular subnetting chart it should be very easy for you to submit any given problem any given IP address turn out to your right so so let me just talk a little bit more about how we can use this multiples of a chart to our best interest so now depending upon the mask number we will have different increment values or different sizes of the subnet that we are going to find so for different increment the size of the of this multiples of eight will vary like obviously for eight it is like each of these particular numbers like 0 8 16 that is the multiples of 8 but if you have other multiples like 16 so that you have to figure out 0 to 15 16 to 31 32 to 47 48 to 63 right just make sure you don't get confused because 16 would be the network address of the next subnet okay so you have to just be careful in this particular place right so similarly for 32 like we had in this previous example would be 32 2 63 64 295 and for 64 would be 0 to 63 64 to 127 128 to 191 192 to 255 256 is it doesn't exist in the networking world because it is greater than or 1 octave right so what about 4 4 2 & 1 well you don't really need a chart for 4 2 & 1 you should be able to figure out the size like suppose you have a slash 30 for example and so you know that the increment is 4 so obviously like the first subnet will be 0 to 3 then we have 4 to 7 then we have 8 to 11 12 to 15 16 to 19 and so on and so forth so my point being that for increments of 8 and above this table is good to go of multiples of 8 but for 4 to and one you would rather do it in your mind all right and I also have this powers of two over here and it will help you to you know calculate the the number of subnets and also the number of hosts per subnet okay coming to how we can actually create this particular chart so I mean if someone looks at this chart for the very first time it it will look quite overwhelming I will look at all these numbers all these rows all those columns and I mean oh my god how the hell am I supposed to make this chart so trust me it is not that difficult I mean you just have to figure out the pattern they specific you know like how just take this for example I mean you have you're mentioning the slash notations so all these slash notations from 1 to 8 fall on the first octet then 9 to 16 for me second octet third then we have 17 to 24 they all fall in the third octet so let's take for example 255 dot 255 dot if you're taking 18 so we have 255 dot 255 dot 192 dot 0 right so that's pretty much straightforward so just keep adding 1 1 1 and it's nothing it's not a tedious task now coming to the actual mask number this will help you identify the equivalent decimal mask because there's not all the times that you'll get us straight you know 255 dot 255 mask number most of the times you will get something called the slash notations this will help you map the specific slash notation to these specific decimal equivalent of the subnet mask right so all you have to do is remember that for the mass number 128 you have the increment 128 so from there on we can derive the rest of the increment so what is half of 128 64 right what is half of 64 - where is half of 32:16 what is half of 16 8 1/2 of 8 4 and so on and so forth till you get a 1 in the end now till now you have a 128 and B at all of the increments from that we can derive the rest of the mass number it's pretty straightforward so what do we do 128 plus 64 where do we get 192 192 + 32 - 24 - 2 24 + 16 to 40 and so on and so forth till you get out to 55 so you can see if this part of the tear of the chart shouldn't be much of a problem now because now you know how you can reproduce it now coming to multiples of 8 it's pretty straightforward I mean you just start off with a 0 8 16 keep you know just keep adding 8 to the previous number huh just make sure that the first column is 0 to 60 4 second is 64 to 128 and so on and so forth - 256 coming to the powers of 2 again nothing much power of 2 raised to 1 is always 2 you know and then just keep doubling it to do the 4 4 - 0 8 8 to the 16 and so on and so forth now not all of you who watch this video might like this particular method that I just explained but those who do please feel free to share this video with your friends and colleagues who might also benefit from it trust me I use this method in my CCENT exam and it helped me tremendously because time is of the essence in any cisco certification exam and this particular subnetting method will definitely save your time just make sure you practice an enough number of times and also be able to reproduce this chart and the vogue board provided to you before the commencement of your certification exam which shouldn't take you more than about a minute or two and you know what I have also gotten this chart printed and laminated to a size similar to that of a business card and I have it in my wallet at all times so that anytime someone throws a subnetting all them at me all I do is take out this card look at it for about 10 seconds and give out the answer without much effort please feel free to comment or post any questions regarding subnetting and I'd gladly help you out

Channel: Arpit Roy

Views: 110,440

Keywords: Subnetting, subnet, ip, ipv4, address, fast, quick, Chart, Cisco, Ccna, Ccent, Icnd, Exam, Certification, Minutes, 10, Ten, under, ccie, trick, magic, number, host, network, networking, second, seconds, fastest, quickest, chart

Id: lskuzOYMVYQ

Length: 15min 40sec (940 seconds)

Published: Mon Apr 17 2017