Subnet Saturday #1: IPv4 Basics | Cisco CCNA 200-301

so now there's there's three main objectives i wanted to cover in this live stream and one was what is an ip address like so i'd like you to pause for a moment with me and think if you were going to right now talk to a loved one a friend a co-worker and explain what is an ip address and there's there's two flavors of ip addresses there's ipv4 which we're going to focus on on this in this live stream and then there's ipv6 we'll leave that for another day but if somebody said what is or you're talking to and said i'd like to explain what an ip address is or they asked you what is an ip address we could say well an ip address is a lot like an address that you'd have on an envelope it like the address for the the street name and the house number regarding how to forward data over the network to a certain address that's it network address the street name and the host address like the house number that's it a fun story i used to live in uh a place not i live in las vegas right now but pre-okay mr mailman do your magic and for granted we also put on the state and the zip code and to make it clear on where it was now the mailman would have to know like uh if this is the like if part of this is the the street street name and part of it is the house number uh the mailman would have to know is it where's the dividing line basically is this the street is it street 382 and house 550 or is it street number 38 and house 250 or is it street 3825 and house number 50. you see there's there's got to be some delineation regarding you know which part is the actual street name and which part is the actual house address you with me because if we don't have that information the info the the letter won't be able to be delivered correctly so in the big picture bob is sending a packet or wants to communicate with a server so at the application layer let me make sure i can see this in my today's stand brought to you by palo alto networks let me just make sure i can see that right there all right good enough so as bob is bob's computer is communicating with the web server at the application layer it's going to be using things like http at the transport layer it's going to be some i'm moving that out of screen wrong direction there we go let me bring this full right there there we go all right at the application layer bob is going to be bob's computer is using http or some application layer service at the transport layer layer 4 it's going to be using tcp because that's how http was written and at layer 3 which is the network layer where bob's computer is going to add on those addresses the source address and the destination address and that's the folks would like to talk about in this live stream is the details more details for an ipv4 address and i thought you know i get i don't have a lot of free time but i have a little free time and so oftentimes what i'll do is i'll come up with what i think are creative or right interesting ways of teaching something and so i came across an idea and i thought i'm going to give this a shot so i test i test drove this on a couple people um the first time it didn't go well i wasn't prepared enough and then the second time i asked my wife deena if she would uh uh let me share her with her something about ip addressing she goes okay she's a she's a fantastic woman she's an artist singer performer she's she works for cirque du soleil she sings it oh um amazing show if you ever have a chance go co goosebumps just amazing amazing music amazing artists anyway back to the topic so i i said i'd like to tell you about ip dresses and i then with some preparation shared with her what i'm about to share with you regarding ip dresses and she goes oh i get it i thought okay great it's ready it's ready for prime time so i have um i have some rulers that i'm going to use as far as rules associated with ipv4 and i hope you like them so these rulers are going to talk about ip address fundamentals now i p the acronym the letters i p stands for internet protocol but we really don't need to memorize that because we just call it ip it is the layer three it works at the network layer logically in the protocol stack and that's why it's referred to as a layer 3 protocol and when we're talking about a packet that has the ip header information added meaning bob's source ip address the server's destination address when that's added that's added to that data before it's sent and we can refer to that information the ip header with the addresses source and destination along with the payload which is the transport layer and the data and the application layer we can refer to that chunk of data as a packet and that's why oftentimes we call things packets in networks is because it's including that layer 3 source and destination ip address so as far as the fundamentals go this is a fun game we can play there's five things what we're gonna do is we're gonna go five four three two one got it that's our plan for right now so as far as the the five things the first thing we want to be aware of with iep version 4 addresses is that there are four numbers i'm looking at the screen to make sure they're not upside down there's four numbers in an ip address ipv4 address four numbers that's it so four numbers that's it now those four numbers are within a certain range meaning each of those four numbers is going to be within the range of 0 through 255 that's the rules now we're not always going to use every single possible number but if we see an ipv4 address and any one of the numbers is like more than 255 it's not a valid ip address so the range for each of the four numbers is 0 through 255 also to make sure that we can know which where the numbers start and stop each of the four numbers are separated by a period so it's an ip version for address is four numbers long separated by three periods yeah there we go i crossed i was over holding off the period over here so four numbers long separated by three periods here's an example of the four numbers and the ranges for those four numbers i should say so four numbers long zero through 255 and those four numbers are separated by three decimals three points three periods and so because these numbers are decimal now decimal simply means the number system that most people in the world use humans like zero one well one two three four five six seven eight nine ten base 10 that's decimal and so what this is referred to is dotted decimal so if you ever hear somebody say dotted decimal what they're referring to in an ipv4 address is four numbers each of those somewhere between 0 and 255 inclusive and the four numbers are separated by three periods so that's the mystery of dotted decimal is they're referring to an ipv4 ip address okay here's an example of an ipv4 address here is 10.193.2.40 so it's four numbers long separated by three periods ta-da and ip version 4 address now here's the part that is important and we've touched on it but i want to reinforce it and that is in an ipv4 address just like an envelope with an address on it an ipv ip version 4 address only has two parts and those two parts are the network portion which is a lot like a house number i'm sorry a network portion was like a street name like jones street elm street 23rd street etc and the other portion is the actual house number and computer ipv4 networks they call it a host address or host id so that's it two parts the street that that computer lives on which is the network address and the other part of this beautiful ipv4 address is the actual host address all right so i've got a question for you would it be important if we have an ip dress like this one would it be important for us to know if we know that part of this address over here is the network and part of this is the actual host address like street name house number would it be important to know where the dividing line is like is it here like is this the 10 network and the host address is 42 3.9 or is it network 10.42 and then the actual host address is 3.9 or is the network address 10.42.3 and the actual host address or house number is 9. you see how it's really important to know where that dividing line is and this is probably the most important part of this initial discussion we're having on ipv4 there's a way that we can identify which portion of an ipv4 address which portion is the network on the left and which portion on the right is the actual host address or house number and we can do that by using this the mask the mask is the mechanism that tells us where that dividing line is and this has a few names we could call it the mask or subnet mask but the key is the mask is the guy who says uh the dividing line is here or here or here based on an ip address that's it so an ipv4 address let's do a quick review and i don't want to tell you how that we're going to do a separate video on the mechanics of how a mask identifies that but let's do the 5-4-3-2-1 game there if somebody says hey can you tell me about ip dresses i'd like you to practice this and you can pause this in the replay pause pause it and replay it a few times and just get down pat so if somebody says hey tell me what you know about ip addresses again ip version 4. we say well you know what i know five i know a few things about ipv4 addresses and starting off there are four numbers in an ipv4 address each of those four numbers are in the range of zero through 255. it can't go to negative numbers and it can't go greater than 255 for each of the numbers those four numbers are separated by three periods that keeps straight it's like uh where one number starts one number stops they're separated by three periods sometimes these ip addresses are referred to as dotted decimal the dots refer to the three periods and the decimal numbers base 10 the numbers we use as humans is how they're represented when we look at them on computers or on paper or whatever so there are four numbers separated by three periods there's only two parts of an ipv4 address that's it there's the network portion it's not like a street name and then there's the house address or the host id the host address which is like a house number on that street and so over on the right hand side i'm sorry i'm doing this all backwards for you but i mean i have to flip everything in my mind as i present this because you're looking at me so on the left hand side over here is going to be the network portion and on the right hand side over here is the host portion and then because it's important to know which portion is the network and which portion of the host there's a dividing line and there's a device a mechanism that's used for the dividing line and that's this bad boy right here it's the mask the mask points to the dividing line everything to the left of that dividing line is the network everything to the right of that dividing line is going to be the actual host address and that's the only way we could know now there are some defaults on how a mask operates but it is make no mistake it is the mask that's dividing the network portion from the host portion so what i thought would be fun to put these rulers away is let's let's have some fun and uh this is gonna be a lot of fun for both of us and let's look at our look at our topology so here in our topology i've got some addresses let's see here 42 3 10 42 3 9 77 okay great yeah this will work all right so let's go ahead and look at this ip address right here on the client pc its ip address is 10.42.77.238 and i just so happen to have a ruler with that ip address so here's the ip address 10.42.77.238 now we know you and i just based on our friendly conversation today we know some basic information about this ip version 4 address this logical layer 3 address that's used for you know assigning addresses inside of a tcpap protocol stack we know that part of the we know that there's four numbers 10 42 77 238 we know that those four numbers are separated by three periods here here and here make sure it's not upside down that'd be bad and we also know that part of this address the part over here on the left hand side is the network portion somewhere over here and the actual host address is somewhere here on the right and my question for you is where is the dividing line in this ip address if we were going to identify like okay the dividing line is here network and all the rest is host or is it here network and all the rest is host or here networking what is the dividing line here and what i would like you to get in the habit of saying because it's really important is we don't know we don't know where the dividing line is because that's the job of one specific device and that's this bad boy if we don't have a mask that tells us where the dividing line is we don't know where exactly that dividing line is and so it's the mask's job to go ahead and indicate where the dividing line is between the network portion here on the left and the host portion somewhere over here on the right so i thought to myself self how can we make this visual and here's how we can do it i created a mask i learned what kind of solvents will remove the edges of a ruler i tried several different iterations and this uh this will work so here is a mask and the mask is the dividing lines this black line right here is the dividing line between network and everything to this side to the left is going to be the network address and everything to the right of the dividing line is going to be a host so if we took this address here and this is the dress right off our computer so i'm going to bring that back for a moment so this is bob's computer 10.42.77.238 that hasn't changed here's the ip address in dotted decimal four numbers three periods um and if we use this mask right here like that there we go let me line that up okay so now with this overlay of the mask which is kind of how it works by the way we can now say oh the mask that has a dividing line everything to this side is the network so with the mask like this the mask would say this is the 10.42 network just like the street name that's it and this part over here over to the right would be the host address so we could say that this is host 77.238 this one this one on the network 10.42 just like that all right let's do it again based on this ip address no that's too mean yeah let's do it based on this ip address all by itself which part is the network and which part is the actual host address like street name and house number and if you're saying keith is this kind of a trick question because you haven't shown us where the mask is going to be you'd be spot on i want you to think every time when you see an ip dress we don't know until we see where the masks dividing line is between the network portion on the left and the host id on the right so in this case if we put the mask here like that what that would mean is that this is the street or network id of 10 and the host address would be everything to the right of that oh my gosh my brain is on total flip mode because of so the network id would be 10 and everything from this portion going over this way would be the host id so this would be the 10 network and this is host address 4277 238. all right let's do another one a different address how about this one let's do this one so the ip address here is 192 168 25.201 that's the ip address my question for you is which portion of this is the network somewhere over here and which portion of this is the host address somewhere over here and what should we be if you're thinking well keith i need to see the mask before i can know where the dividing line is between network and host you'd be spot on so let's go ahead and put our mask let's put our mask right here so if the mask is right here so the dividing line is right there that means that this computer with the the device that has this ip address the network is 192 168 25 that's the common like street name for all the devices on this logical ip network and the host address would be 201 just this last part right here all right let's play a game let's play a game based on this topology and the game is same network or not same network so we have this client pc at 10.42.77.238. we have this server at 10.42.3.9 and i happen to have both of those right here and i will go ahead and put them up all right those are the two ip addresses let me bring them up on video here so my question for you is based on these two ip addresses 10.42.77.238 which is bob's computer and 10.42.3.9 which is the server are those two iep addresses for those two devices are they on the same network or not meaning based on the ip dressed the ap dresses on the same network what do you think about that now the benefit of pausing here is to realize that it depends it depends where the dividing line is if the dividing line is right here between the 10 and the 42 those two computers are on the same network the 10 network and in fact let's just bring our mask up to do that if the dividing line i should have brought more i should have brought more hands to the party let me go ahead and uh just grab those right there that'll work if the dividing line is right here between the 42 and the 77 and 3 respectively that would mean once again that they are both on the same network because they're both on the network of 10.42 but if the mask was here these two computers would not be on the same network one computer would be on network 10.42.77 and the other computer would be on network 10.42.3 and those are two like two different street names like elm street and figueroa or maryland parkway and las vegas boulevards are two totally separate logical street names or network addresses and those two devices if they were using those respective network addresses they would not be on the same vlan the same network all right so um i think that's what i wanted to cover in fact i'm sure of it i wanted to cover a basic few things in this uh video about ip dresses so let's do a quick summary and then i would be happy to open it up for any questions if you have them all right there you go all right ipv4 fundamentals as i get my rulers in line here so many rulers okay if somebody asks about ip addressing ipv4 we could tell them about five things get your hand out five things and start off with one of the first things is hold on one second i get my rulers in line i should have numbered these better oh there it is okay first thing is there are four numbers long meaning four decimal numbers long each of those numbers have a range and that range is from 0 to 255. so if you see an ip address an ipv4 address that has something higher than 255 is one of those numbers something is off to separate those numbers the four numbers we use three periods so here's an example of the ranges and the three periods separating those numbers here's an example of an ipv4 address 10.193.2.40. and this ip address and every ipv4 address has exactly two parts to it it's got the network portion which is like a street name and it has a host portion which is like a house number on that street so it's the network address first and then the actual house or host address on that street and the dividing line that controls that is the mask and then we did some visualizations with a mask which i will just do here as a repetition and there we go so for this address right here if the dividing line is like this what that means is that this is network 10.42.3 based on what the mask says the dividing line is and the host address or house address is nine if we use a different mask like this the same ip with a different mask this now means this is street name 10 the 10 network and the house address is 42.3.9 that's the host address on that street all right well that was a lot of fun it was it was a lot of fun to put together i went through quite a bit of solvent i actually took off the actual numbers on these rulers using isopropyl alcohol and some elbow grease to get those off and i will repurpose all those probably keep them for another discussion so we've covered uh the basic fundamentals of an ip address so it boils down to this ipv4 addresses are four numbers long zero through 255 of the range separated by three periods there's two parts in an ip address the network portion of the host portion and the dividing line is the number one thing that we need to be aware of isn't dividing the host network from host and that is the mask so if you're asking or thinking okay i get it i understand conceptually how that works meaning that that the mass does that job and what we'll do in another stream coming up we'll do it i'm going to do these every saturday same time same bit channel and then i'll put them in a playlist so if you go to my channel go to playlist there'll be one for i'll call it uh subnet saturday um but in the subnet saturday what i'll do is i'll put these in order so you can catch up you can review you'll be easy to find them and then in our next live stream for subnet saturday what we'll do is we'll take a look at how how does that mask identify you know which portions of the network and which portion of the host and we'll remove the magic there so just one logical step at a time piece by piece it'll it'll be a cinch so i'm going to take a quick peek at the queue and see if there's any burning questions i also realize that there's a lot of people who are answering questions for other people which is fantastic i also want to point out um as i take a look at the cue if you have not yet subscribed to keith barker networking here on youtube please feel free to do so we'd love to have you as part of the community if you hit the alert bell it'll give you a heads up when i have new live streams and uh for more training we also have a boatload of training i work full-time for cbt nuggets we have a boatload of training also um at cbt nuggets it's quite amazing jeremy chara myself jeff kish knox hutchinson and uh and network chuck and many others uh creating that content there so that's another resource as well so let me put on some music i'll put back on my topology here for a moment i'm gonna check out some questions in the queue and i will be right back [Music] all right i don't see anything pressing and burning that needs to be addressed at this moment so um going forward i've got live streams on sundays and also some on wednesdays i'll keep you updated in social media when all those are happening i appreciate you being here again click on subscribe click on the alert bell make sure you don't miss a single session regarding ccna subnetting or anything with networking i love ip networking so we'll see you in the next stream meanwhile i hope this has been informative for you and i'd like to thank you for being here bye everybody [Music] um

Channel: Keith Barker

Views: 27,126

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Keywords: ccna 200-301, ccna certification, subnetting, subnetting made easy, subnet mask, subnetting tutorial for beginners, subnet mask and ip address, subnet mask explained, subnetting in computer networks, networkchuck ccna, networkchuck network+, ccna training, ip subnetting, ip subnetting made easy, ip subnet mask, ip subnet mask and default gateway

Id: Y8ZwmAxnOL0

Length: 27min 24sec (1644 seconds)

Published: Sat Jan 11 2020