Subnet Saturday #9 : IPv4 Reverse Engineering | Cisco CCNA 200-301

[Music] [Music] [Music] [Music] [Music] [Music] and welcome everybody to a really great subnet Saturday my name is Keith Parker if you joining us I've got a few words to say and that is welcome aboard I have so many thoughts I'd like to share with you all I'm gonna hang on to most of those until after we finish the topic at hand which is reverse engineering for ipv4 including the new CCNA exam my thoughts on that the things I've been hearing the things that I've been seeing and also Cisco live coming up with the you know the kovat 19 thing going on and some tips for that so I'll cover all that at the very tail end in the Q&A section so our focus today and I'm so tickled pink that you're here our focus today is ipv4 reverse engineering now for those of you who have had the equivalent knowledge or you've been with us through these subnet Saturday sessions we've had I think this session number nine now which is getting up there I am I'm hoping that you have the knowledge from the previous eight sessions that we've had together as we've enjoyed our time together from the basic foundations of what an ipv4 address is and how the mask works and custom subnetting and very like subnetting binary to decimal decimal to binary all those really cool tricks that we can now do the finger game the block size and now I'd like to do is share with you a really important aspect about ipv4 subnetting and that is well let me tell you about an experience that I had early on in my career this is when I was first learning subnetting and not really good at yet I was on the like the 41st or 42nd floor of a building in Los Angeles and I was at one machine and it was after hours I was allowed to be there I wasn't hacking I was allowed to be there and as I was configuring the IP address the DHCP for whatever reason wasn't working well and they told me that the default gateway was gonna be the first IP address on the subnet and so I looked at that client's IP address and I thought to myself oh the first valid IP address on that host is gonna be on the network is gonna be 1.1 put it in didn't work I thought uh-oh I'm in trouble and I was in trouble for real because I didn't have enough knowledge at the time to reverse-engineer it so what I'd like to do in this video our objective is to take an IP address that we're given and say okay based on that IP address what subnet is this guy on what street like look at the IP address based on the mask and the IP address is he on Elm Street or 1st Street or 21st Street or we would be using network addresses like use that 10.16 dot to our ten dot 16.4 or what is that network that that customer is connected to so leveraging everything we've learned up to this point that's our objective for this video and for this live stream and I also want I'm looking at the queue I'm so grateful for everybody being here if you have questions for me directly there's a lot of people in this room right now if we're willing to help and I'm very grateful if you have questions for me to directly hold on to those and at the end after we finish I'll do a quick pause we'll come back for Q&A and then you can direct those questions directly at me if you'd like it might be more than happy to take a look at each and every one of them and give them a shot our focus again is on CCNA and that topic oh my gosh I've got some great new ideas too I'll hold that for the end all right let's take a look at our topology and and let's let's play a what-if game I'm gonna move this this is called epic pen a lot of people ask me hey Keith how do you write it on top of stuff I use this it's epic pen and I can change my colors like this Boop epic pen and there's an eraser so here's the eraser well what did you learn in the livestream well keith uses epic pen to write on top of virtually anything web pages whatever you need so I'm gonna go ahead and hide that and skra head and scooch it over here alright just like that and I will put on a little camera here hello and let's you know instead of this topology let's bring up a chalkboard and just have some fun from scratch with a brand new chalkboard that'll work let me bring up another layer here also behind the scenes I use a program called painter but painters just another application so all right let me make sure my chalk is working hello yeah seems like it's working great so I'll back that off okay let's do this I made a few notes here too so I can stay on topic here today let's imagine as I pick up my other pen and let me go ahead and pick on a color like this for the topic oh by the way if I haven't mentioned it's great to have you here also if you don't want to miss any updates when I have a new posting out or a new live stream I do about three a week now filling up the CCNA library including subnetting click on subscribe make sure you're gonna get those alerts and I'd love to have you if you have a friend you can study with that's always better better to study with a friend alright so let's take a look at a host let's imagine we have a network here boom I'm gonna draw it old-school there's a network there's a PC that PC represents a device with an IP address and there is a router and so perhaps that router maybe it's our one and it's got connectivity out to the rest of the worlds making sure it's not hitting my face no just put an arrow there to remind myself don't don't draw in Keith's face or behind Kees face so here's our PC here's the router and we have a network in common between there so just maybe the let's see here let me it's the 99.04 let's do that let's do that and let's imagine that this PC right here has been given the IP address of 99.04 cause let's pretend that didn't happen because I want to walk through a process how we can reverse engineer that and we'll do it together so I'll leave it up because I already wrote it so 99 0 to 80 5.0 let me back that off when one note I need one more hand there we go a five dot and let's use dot one this last twenty three so if we went to that PC and we looked at it and didn't if it's a Windows computer would be ipconfig that'll show us the IP address in the mask if it was Linux we do ifconfig or Macintosh that the CLI be ifconfig or we could use the respective gooeys on those platforms as well and that assembly means that the first 23 bits of this IP address are the street of course in ipv4 we call that street a network and it also means that the last nine bits are the actual host address or house address which in a computer network we refer to as host ID so all that we've talked about previously and now my question is if we were just just given that IP address how do we how do we verify what network this clients on because that happens a lot especially if you have two devices I did a tweet this morning about and also put on LinkedIn and Facebook as well and it had Bob the user who was in VLAN 10 and the printers in VLAN 10 now VLANs are a layer to construct and what happened was that Bob couldn't print why Bob's print I love Sean Powers response something about a dot matrix printer from 1980 or something with it or inkjet printer with the ink all used up Sean Powers is a great great guy he's on our team at CBT Nuggets a lot of other good feedback too but it wasn't because he didn't have the right printer driver it wasn't because Bob's computer it wasn't powered on it was because they were in different IP networks it was like the printer was in network a an IP subnet a and Bob was in an IP seven that be logically even though they're in the same VLAN there was a miss configuration so if we have this IP address here's here's how we can determine that this is the actual network if it is and I'm gonna check my work because as we go through this process you'll be able to do also in a certification environment the new exam for CCNA based on probably ten hours of be watching people's feedback on it on YouTube it's it's a bear I mean it's really going to task you to see whether or not you can figure out what the details are based on the data they give you it's not just a simple walk in the park and IP subnetting was an absolutely tremendous big li big li oh my gosh I can't believe I said that a tremendously big part of that all right so here's what we're gonna do there's there's just a few steps in calculating what network this PC is connected to let me go change my colors here a little bit let's go let's just call this Bob's PC oh hold on a second I thought I was changing my colors give me a moment oh yeah here we go I like to play with new tools all the time sometimes there's a learning curve like just now so let's say this is Bob's PC so we can refer that as Bob's computer and here's what we would do the first the first step if you're gonna jot these down or recall them that's great the first step is to identify the block size and the way we're going to identify the block size is the same way we've identified the block size forever it's the value of the least significant bit so if you're just joining us we're so glad you're here in this channel in this group if you need to back fill this information there's a separate playlist just for subnet Saturday that has all the details that build up to this point so enjoy today backfill it tomorrow and then join us for the next subnet Saturday or catch it in the play this whatever is the most convenient for you to catch it in so we're gonna ID the block size so this is a slash 23 that's the mask so we'll put our values here for one octave data 1 2 4 8 16 64 as I missed 32 it was a long night last night great night though I went and saw play had a lot of good fun 1 2 4 8 16 32 64 128 all right 1 2 3 4 5 6 7 1 2 ok I slowed down 3 4 5 6 7 8 and by the way if I was taking an exam you I'd be doing literally exactly this just so I don't make a mistake or guess that it wrong because sometimes on paper too IP addresses look like hey these look like they're right next to each other when they're not in the same subnet so the first step in identifying the subnet that this computer is on is identifying the block size so the mask and I'm going to use white here for a moment so this is the this is going to so the first 16 bits are all network so this is going into the third octet and over here to the left is the fourth octet just so we're on the same sheet of music and if we're going for a 23 bit mask I'll put the mask right here the mask up to this point would be 16 so 255 255 16 then going into the third octet I'm just counting out loud so B 17 18 19 20 21 22 23 that's what we're going for I put a big line here I'll go ahead and use a separate color for that let's go ahead and use maybe grain boom that's our dividing line and we'd have a 0 for that bit we have a 0 for that bit of the mask so on this side we have Network and over on this side we have host regarding the bits and that's because the mask is controlling which part of the IP address is the street and which part of the address is the host and that's how it does it so the block size getting back to our point here our block size is the value of the least significant bit which is 2 so our block size is 2 that's the first step block size of 2 then what we could do in that third octet and this is a bit painful so let me let me hide this layer just for a moment if we have a block size of 2 in that third octet here's here this is painful but I want to show you how painful it is and then I'll show you a solution for it and let me bring up another layer here we go so if our block size is 2 and I will change my color here a little bit there we go so if our block size of 2 and we're in that third octet I'm just going to put the third octet here for that third octet our subnets are going to be let's imagine we're starting at 0 0 and then the block size is 2 we'd add 2 so next subnet would be 2 then 2 more so the next type node before next subnet would be 6 next 7 it would be 8 next subnet would be 10 you with me I'm just taking that third octet we're just adding to the block size to determine the next subnet in the next subnet the next 7 to the next subnet so if we were starting with 85 which was the example so if we start with well that's not the actual network so we start with that third art that whatever the networks are we have the block size we've covered that previously now if we're trying to get up in the range of the 80s how many do we have to go here I mean we're gonna need like three sheets of paper just to you know add to add to add to add to add to for the block size forever and ever and ever and that's gonna take a long time so instead of writing all these subnets out which we have done previously I just want to show you a shortcut where we can very quickly go to the actual subnet and identify what that sudden that is so let me go ahead and clear that layer bring back the previous later layer and here's the trick so the first one is to identify the block size and then what we're gonna do is this third octet which I will I was just circle here let me get a the right pin for this about that color that'll do so in that third octet what we're gonna do is this we're gonna simply divide the octet now when I say the octet this is the octet where the last bit is so in our math the last bit is in this third octet somewhere it could be the last bit or the first bit or in this case the seventh bit over from the far left you take that octet and you divide it by the block size I probably smell size right it looked better okay so if you're not like super great at math you don't have to be here it's not the concept is number two we want to take that octet where the dividing line is somewhere in this octet so we'll take it 85 and we're gonna divide it by the block size and so in this example with this last 23 bit mask the block size is two so we're gonna do two into 85 that's it so 85 divided by two so if you want to just longhand like we some many of us learning in school we would simply say well 2 goes into 8 4 times great see 2 times 4 is 8 then you work on the next number the room this way I have 5 there 2 goes into 5 only 2 times then there's a decimal point great and then there's going to be a remainder now here's the deal we don't care about that remainder all we're after is how many times does the block size go into that specific octet cleanly and then whatever that fraction is for remainder you just round down to that whole number 42 that's the second step so Keith let me back up here you're saying that if you have an IP address which we do and a mask the first step in to identifying what subnet this customers IP address is on is identify the block size step number one great and then take that octet from that customer's IP address whether it's the second octet or third octet or fourth octet depends on where the mask ends so wherever the mask ends in that same octet take that octet and divide it by the block size and then if there's a remainder forget about that remainder we don't care we're just looking for how many times does the block size go into that octet cleanly so in this example we have the block the block size goes in 42 times so far so good the next step is to go ahead and multiply so we're gonna multiply the block size I'm gonna put BS but I want you to know that that be S stands for block size the block of address is the block size just for abbreviation here nothing else just block size we want to take the the block size and multiply that by how many times by that result so basically 42 how many times did the block size go into that number 42 times or take the block size times 42 which is 42 which is the block size is 2 times 42 equals and let's do the lung math on that I'll do it right here so 2 times 42 2 times 2 is 4 and the reason I'm doing a longhand is because in the heat of battle in the in the moment of an exam or just to be sure we want to get those numbers right and so you can I mean we can look at that say 42 times 2 is 84 but just take a moment to it the longhand it won't hurt a bit so 2 times is 4 or 4 times 2 is 8 that's 84 equals 84 and then the last thing we're going to do is we are going to place that octet in that position and then zero out everything the right of it so what that means is that this customer with this IP address of 99 0 to 80 5.1 with us last 23 masks is and let me get a little bit more room let me I have an eraser tool and I know how to use it and we erased some stuff here I'm gonna go ahead and already saw that and make it bigger drying tools are fun my daughter Amber and I have a few other kids they're also very very artistically gifted and it's it's fun it's a lot of fun so I'm going to just make some room up here also I'm going to remove my face even more real estate and let's go ahead and continue this discussion then so if we take this address the IP address of the customer and I'll use a different color for this let's go for that color if it's 90 9.0 dot and instead of using that octet we're gonna use this octet which we got by taking the block size dividing it into that dividing that block size into that number and then finding out how many times that goes in this gonna be 84 and then well everything else to the right will be 0 / 23 so what that means is that is the network that that client is sitting on where before I think we would go back to my other notes which I was rushing on let's go back and take a look Oh what did I do with it oh oh it's right here it's right here this is the network that I guessed originally that that computer was on that's not the right subnet this is not the right subnet this is actually the 84 subnet that's because I just slapped it up there said that looks right 0 at the end this is the 99 0 to 80 for subnet that this clients on now the other question and this can be very helpful is how do we identify what the range is for this subnet and this is a trick that you and I have done many times previously in these subnet Saturdays and that is we take the block size so the block size is 2 that hasn't changed and that's gonna be our next subnet in that third octet so 99 point zero point our dot plus 2 more 86.0 / 23 our next subnet and the next subnet after that would be two more and two more just keep adding the block size assuming the mask is the same so our range for this subnet would be host 80 4.1 through and then we can't go past the next subnet so the next subnet is 86 Seve 85.2 54 with the 255 address being the broadcast address for the subnet and then for this next one the 86 network it the next subnet would be eighty eight dot zero slash twenty three and so the range for this network would be eighty six dot one through the next subnet minus 1 which would be eighty seven dot 254 with two fifty five being the broadcast address for subnet B we'll call it so that's the process for reverse engineering based on an IP address reverse engineering what the actual subnet that that customer is on without having to guess now the reason I came up with this and I you know sometimes as a trainer I've been training for a long time and working in the field for a long time sometimes as a trainer I hear ideas our thoughts or ideas I think how can I make that better or how can I make that more clear to a learner and sometimes it's natural like with a quick analogy and sometimes just like how would a average human do this and that's why I came up with a finger game like eight or nine years ago to calculate how many bits are needed for subnetting or for hosts addressing because I thought I need a I need a way without saying the powers of two if you noticed in this whole subnet Saturday I'm not training you to do the powers of two we have fingers that we take into an environment with us every time and if it's a certification environment or a production environment our fingers are there and we know how to calculate the block size based on the least significant bit and that we can calculate based on that the new subnets we also applied that to variable length subnet masking in the previous video so here's what I'd like to do let's clear off the whiteboard let's take another I like if you want add one more piece the reason the calculation of dividing the block size into that octet is good is because again if it's like a if that third octet is 220 and the block size is 4 you're going to write out 4 8 12 16 etc all the way up and it just takes too long to figure out the next subnets next subnet to get to that point the dividing the block size into that customer's octet where the bit where the mask ends it's just a shortcut to get there quicker so you don't have to have three sheets of paper to calculate it so let's do let's do one more and I one of the things about me is that you might want UART me all right now I have a little bit of an inferiority complex in general I I'm 55 and I have two CCS and certifications for many other vendors as well and I apply myself pretty hard when I do the various things whatever it might be just like you do and when I was 16 I was five feet tall and I was bullied a lot as a kid not by my family they're great but school in other places I got bullied a lot so I was five feet tall 82 pounds that was my first driver's license I remember it it's like oh my my driver's license keith barker 82 pounds 5 feet tall hard to get a date got pulled over 7 times for by police in my city I grew up not because I was speeding and not because the police were going mean because I just looked like I was 12 or 13 they just stole my parents car for a little Joyride so why do I point that I usually I usually over prepare almost everything I do like all at CBT Nuggets where I spend like you know my full-time job forty hours a week I do about two to six hours well probably six hours to seven hours a week streaming so just for CCNA Wednesdays at 4 p.m. Pacific and Saturdays like today subbed in Saturday at 11:00 a.m. Pacific and then Sunday's CCNA Sunday at 11:00 a.m. Pacific so I enjoy this I love it I love giving back to the community and normally I do some prep like I'll write things out I'll go through them whether it's CBT Nuggets content I'm making or whether it's a live stream like this so I thought what I would do is go ahead and break out of my comfort zone which has already started right now and put up an IP address where I don't know the math on it I haven't done the math on it and I want to go ahead and calculate based on an IP address with you using the techniques we just talked about and calculate what that customers on maybe the scenarios like this you've given you've been given a customer IP address with a mask and you're quittin you've been told yeah the default gateway DHCP is not available but the DHT the default gateway is the first valid IP address in the subnet go it's like how do we do that well we use the same process I think by doing it from scratch again without any preconceived you know idea of which IP addressing on the user house going to go that would be a great chance for us to process it together as I get otherwise the wrong fin process it together and then see that process one more time so let me go ahead and clear my screen right here I was gonna remove that layer that I had added we'll add one more layer and then I'll bring that over plus a little circle cam circle cam up in the right-hand corner there it is alright so let's imagine starting from scratch and I'm just gonna pull one right out of the air let's use a pen and let's say that we have a network and we have a client and this is not Bob's PC it's gonna be Lois as PC and the reason you know that that might be funny is if you've seen other sessions with me you know what Lois and Bob represent to me so we have Lois here and she is connected to a switch port will call this switch 1 and let's call this port 1/15 now Lois is computer is in a specific VLAN and the VLAN that's in is based on the assignment of that port so if the administrator either directly on that switch us or we did through network automation and we push down the commands to it from a controller if that port 1/15 is assigned as an access port and VLAN let's call it 70 Boehm that's the layer 2 broadcast domain that Lois's computer belongs to now normally associate with a layer 2 broadcast domain of VLAN we also normally associate a street now the street is the IP network address so we put an IP network Association on Lois's computer and also any other devices like a router that are in that same VLAN and have to agree oh they should they should agree if they don't agree on the street name they're gonna have a hard time talking to each other and so if you have a piece of cable I like it if you have a brand-new switch and a brand-new computer and no other device you plug it in whatever IP address you put on that computer is the IP address and is the network that that computer is gonna believe is connected to it's just based on configuration and then usually in a network design they'll have the router that's can that's correct with what IP address and what network address it is on that Street so we have some kind of layer three IP network address and let's imagine that Lois's computer is and put this in in white I'll just put over here ten so we use the private RFC 19 at the private address base is the 10 anything the 172 16 through 31 anything and the 192 168 anything so those are considered RFC 1918 private addresses which means everybody can use them just make sure you do NAT before you head out to the internet because the internet will not route those because they're not publicly routable addresses all right we can't internally but just not on the internet so let's use 10.40 2.99 dot 204 all right there we go and I haven't pre calculated that math and for a mask we're gonna use something that's not on a clean boundary not on an 8-bit boundary let's use the 20 let's use this last 28 okay so our task is now if you're watching this in the replay you could pause me right here and take a stab at that right now which wouldn't be a bad exercise because sometimes when we think we understand a concept if we pause and say okay let me apply my skills or what I think is true and we go through it then we get stock Mike oh I guess I don't get that part and then we can really hone in and clarify that piece that's happened to me more dozens of times in my life as I'm learning new things as I try to express them or write them out or calculate them I say oh oh I I don't know well I don't know what the next step or I don't remember how that works but through repetition and through going through times you can gain that knowledge and then once you have them they'll be in your memory longer than if you didn't ever learn and occasionally refresh and you're good to go so the first step we would if we were told okay Lois's default gateway which is right here we'll call this r1 Lois's default gateway is the first valid IP address on the same network that Lois is on now the question is but what the heck network is Lois on how do we know and the process is number one BS and that BS NSA block size in case you're just joining us so identify the block size and so whenever you're stuck or whenever you're starting a problem there's two things that might go through your mind one is I'm gonna write out the values of the binary of the byte of data the 1 2 4 8 16 32 etc and the other one is I'm gonna throw up a finger and start counting how many bits do I need using the finger game one of those two things is usually a great starting point when you're trying to solve a problem we're not asking about quantity here we're asking about the block size so let's go ahead and write out our power our values for a byte of data 1 2 4 8 16 32 64 128 also for the new CCNA based on where you test in the past it we've been given up so the testing is done through view and if you come to company called view view II and in the past they've given us a laminated sheet with a dry erase marker or maybe two of them and you could write on them and then when you're dang cute erase them all and then Hanneman I've heard based on a testing center this may vary that they give you that laminated thing in the dry erase marker and they say don't erase anything and then there's a camera watching you also and they're asking you not to erase anything so I think there being more stringent on making sure that people are not cheating in any fashion possible so here's the thing if you're going into an exam if you've been through these subnet Saturdays and you're going into a CCNA exam or anything that involves submitting well if you get fingers with you check got him you've got this table that you can write out on demand and I've already written out twice in this short video write out the the power of these these values of that one byte of data and that's all you need and then you can start calculating so with this last 28 what we're doing is we're looking at this fourth octet so the 24 bits would be all the way up to here eight plus eight plus eight in the mask plus four more bits in that fourth octet so I'm going to go ahead and just make a note that the third octet goes that way and the fourth octet goes this way and that we are dealing with the fourth octet so the mask is in that fourth octet so where are 24 bits up to this point this is it 24 so we're just going to go up to 28 25 26 27 28 and then that's our dividing line so everything over this way is the network portion or the street name in that IP address everything on this side is the host portion for host addressing and so the mask for that portion would be 0 0 0 0 just like that so what is our block size that's our first step our block size is 16 fantastic and then we're gonna say ok we're dealing with that fourth octet we could just start off with 10.40 2.99 dot 204 and just add 16 at 16 or we can start off with 10.40 2.99 not 0 and start adding 16 adding 16 adding 16 adding 16 you're with me but it would be a long set of all the subnets that we're listing before we ever get to 204 so one solution is let's take the block size and divide that into that number which is step number two and that is the octet / block size and let's do that together so this is 204 I would have picked an easier number if I would have picked a smaller block size if I was planning this out ahead of time but it's a good exercise because any any block size could come up so this is the value from that fourth octet our block size is 16 and 16 goes into 21 time there's a four remainder there you can borrow the one and all that good stuff and then you bring down the next character for so 16 plus 16 is 32 16 times 3 I'm just gonna do it because I want to verify so 16 times 3 just to make sure it won't go in 6 times 3 is 18 3 4 yes - hi great you know I I probably could have done that without having to do that math but I wanted to verify and also I just put that underneath my my face my apologies there you go so the 16 only goes into 44 two times so we bring that up there and then there's going to be a remainder so that's 32 and then we don't actually care about the remainder past the decimal point so now we have our block size we have how many times our block size goes into that octet and then to complete this we're gonna do the block size times how many times it went into the customers octet so this is three block size times result and I will draw an arrow over here talking about this result right here so it'd be 16 times 12 yeah shame on me okay so there's no calculator on most these exams but the math is going to work so 2 times 6 times 2 is 12 2 times 1 is 2 plus 1 more 3 then we're gonna put a 0 here and then bring down the 16 yep so any way you wanted it that math I just shortcut it a little teeny bit but anyway you wanted that 16 times 12 is great as long as you can calculate that and the total would be 2 1 9 so what this then the fourth thing is you simply plug that number into that last octet plug number this number in so this customer so this IP address for this network would be 10.40 2.99 dot 192 with a slash 28 that's the actual network and if we wanted the first valid IP address on that 192 subnet it would be dot 193 and if we are curious of the range for that network how would we calculate it well Keith we could probably use that block size trick we've used like four or five times in these series you're exactly right we use the block size so the next seven that's gonna be sixteen more so I'll put that here at 192 plus sixteen maybe eight zero 208 so that's our next subnet so the range and I'll put this in a different color here the range for this network would be oh goodness here would be 191 are 193 the first valid IP address through the next subnet and this is the last octet there's no more room to play with on the right hand side next subnet minus 2 which would be 206 because the 207 is the broadcast and the next IP address of 208 represents the street name for the next subnet so that's our range so this client on 10.40 2.99 204 is in the network 1042 299 192 this last 28 and the first valid host address is dot 193 and if that's our default gateway that's what we'd plug in whoo yeah I would have chosen a different example that had less digits in it but that's how it works now does this technique work with any mask and any IP network any customer IP address the answer is yes if the mask is this last 24 the block size is one that's actually a pretty easy calculation if it's a slash 22 the same process works identify the block size divide that block size into that customers octet where the masks ends and then take the result of that times the block size that's your subnet and then the next block the next seven it beyond that is the block size again and again and again and that way you can calculate your ranges very very easily so reverse engineering and ipv4 address to determine the actual subnet is a really important skill because there may be situations in production environments and in certification both where you're given an IP address and you're a far from host and you're asked which of these two or three other IP addresses if any are in the same subnet and you just you look at the ranges it's like okay what's the block size what is the subnet what is the range based on the next subnet in the block size and you know adding the block size again and again again and then listing out the ranges say Oh easy and that although I did hear longhand I did everything with a few practice runs you're going to be able to do this consistently and do it accurately and based on all the feedback I've gotten regarding the new CCNA you're gonna want the experience and the knowledge of how to understand what IP addressing is understand masks and understand subnets understand vlsm and be able to reverse engineer as we've done in this video so that's what I wanted to cover and we were able to do that in about 39 minutes also I got a question let me make me save the note for that for the Q&A I just want to make sure this is nice and tight so here's my goal is to cover this topic which we did thank you very much for being here and then go on a short break and when we go in that short break what we'll do is I'll get a drink of water which is always great and then we'll open it up for like chat at QA if you want to join me let me give you a link for discord - I've got one and it is right here and I put this in the in the chats so you have something to go to hold on one second make sure it's right okay great so I just added the discord link if you'd like to contact me if you have questions you'd like to ask me directly you can join discord it is also for you just like YouTube and you can direct message me there if you want also we've got a lot of great people who are answering questions if you have a request for a video that's somewhere on the CCNA blueprint as far as the topic in that blueprint I've got we've got six sections for video requests like I'd love to see a video on this many times the video already exists another channel number or a moderator will simply say hey here's a link for that exact video that Keith did like eight years ago same technology still works and sometimes it'll be a new live stream that we recently did so there's a spot on this cord to request those there's also a spot for discussions or your an expanding tree and routing and layer 2 switching and trunking and Network automation program ability all those things so whether you have a request for a video for CCNA level stuff or you want to ask a question or a challenge question and get feedback and if there's ever a spot where there's a discussion going on and you'd like a not an arbitrator but you'd like my my two cents on it just throw in the at Keith I think it's Keith Oh GI T in the channel and one of the moderators as well and that'll get my attention and I will jump in and answer it sometimes to the best of my ability sometimes I just give a clue or based on what I think would be the best learning experience provide you additional information so join our discord server it's free and also I want to share with you a link for submitting because I'm looking at the list of people in the room and there are some new people so let me give you another link here lots of screens I've got this green and this green and this lots of screens so that link I just put in is for just a concise playlist regarding subnet Saturdays so I think this is our session eight or nine maybe nine so if you want to start from the beginning with subnet Saturday like I don't know anything about ipv4 addressing I realize it's super important to get that knowledge start there and maybe commit to a few hours a week of just enjoying watching learning if you have questions join discord ask questions get answers it's a great resource the second thing I'd like to do is if you are working on your CCNA I made also a playlist and this is mostly for people who are new this is on YouTube also it's free of all these live streams and also a few extra videos and tidbits that I've worked in and then I've organized them in mostly a logical fashion that is very similar to the blueprint where network automation is going to at the very end we haven't done those yet so stay tuned those are coming IP routing is near the middle layer 2 switching is near the top so based on the blueprint so you can kind of go through in a logical progression and then as we do new live streams which I got some great ideas by the way from discord so thank you very much those ideas including additional ipv6 static routing which is a big deal for CCNA I've recently discovered that it's more important than most people are going to expect so I want to prepare you for that anyway so those will be added as time goes on and then also just one last piece here before we take a short like 1 minute break for me to get a drink of water is many of you know my full-time gig is at CBT Nuggets where we make it's a commercial site it's not free its subscrib subscription-based and if you're interested in learning more about that here is the here are some like content there and there's a 7-day free trial there's no obligation I think that it's a lot like the story of Goldilocks and the three bears you know the Goldilocks for those of you who are familiar you know for those of you are new to Goldilocks I'm glad I can tell it to you for the first time Goldilocks shows up at the Bears house this is a fictitious story she showed up at the bears house and there's three bowls of porridge I believe or some kind of a food substance and there's Papa bears and it was too hot and there's mama bears and it was too cold and there's baby bears and it was just right but you know what if push comes to shove Goldilocks could have just gosh darn eaten any one of those and survived if she needed that food to survive any one of those would have done she could make Papa bear's let it cool off a little bit take mama bears and say it's but it's gonna keep me living and baby bears was happen to be okay as is the point of that story for me as far as learning is that there's a lot of resources you can use to get CCNA certified a lot of those are free and they're here on the internet that's one thing I love about YouTube is that there's so many people helping other people learn for free I don't monetize at this at this at this time I don't monetize any of my YouTube stuff at all and I'm getting close to a hundred thousand subscribers and that's you by the way so thank you for enjoying it participating all that good stuff by subscribing liking it that lets others know that hey this might be something you want to look at in your drain through CCNA and so there's lots other great content there's food me they've got courses CBT Nuggets we've got like 52 hours of course material on season eight plus labs and they're concise so we we hone in but here's the topic here's fun here's a lab reinforce it and move on 52 hours of that with Jeremy Chara Chuck Keith and myself who created that it's fantastic but it's not free well my point here is that if you want to get CCNA certified I would encourage you to learn the content there's lots of ways of doing it including mostly free ways not like a highway but ways that don't cost money and whatever works for you whatever whatever you need to do for your to learn it I would go for it so thus I want to make that statement that there's a lot of great people with a lot of great content free on YouTube and there's a lot of great paid resources as well including CBT Nuggets and other companies that can be used but if you have the desire that's where I'd start you know what do I want to accomplish in three to six months and then allocate the time to do it and then start studying packet tracer I said this before but packet tracer from Cisco is free and it'll do everything that you need it to do to help give you hands-on practice for the CCNA level content including as I've learned in the last 48 hours a bunch of details on wireless so we have wireless in our CCNA content CBT Nuggets and it's also important as a CCNA candidate based on the blueprint and I have not seen the exam yet so I'm just talking about things that I've observed is to be able to configure a controller or if you're not going to do a simulation at least know what is on the you can configure should configure how a controller works with access points which by the way we're gonna include that in our videos here to make sure that you get a nice overview and one last thing before I take a short break and then we'll come back for Q&A is this if you have a question for me starting now if you do an at Keith Barker and then your comment so I can see it that way I have to scroll through the long list that's already there and and oh yeah one difference one significant difference between these live streams and the content here on YouTube and my full-time gig at CBT Nuggets is that a CBT there they're concise they are like this topic you're in here it is here's why it matters here's an analogy to help you remember how it works here's a lab to support it and then we're out and this is more like the instructor hours where a little bit more relaxed I'm here in my recording studio and unless it's a house in Las Vegas that I record out of and it's a little less structured for like chatting with the instructor chatting with the not the professor because I don't have a college degree but chatting with the instructor about the topics giving you an overview of it what it is then sticking around for Q&A so that's and also we're not in this channel there's no way that I can reach the depth and the hands-on practice that we have at CBT Nuggets as well so that's a significant difference alright I'm going to go ahead and give you some music for a few moments and get a drink of water and when we come back I'll be happy to take Q&A my focus would be any questions about our topic today which is reverse engineering ipv4 would be preferable my second choice would be anything related to the CCNA 200 301 blueprint and my third choice anything that's at the professional level even though there's some pretty deep topics at CCNA or anything out of the scope clearly out of the scope of CCNA I'd love to take those in discord and the discord server so save those for me if you have them there put them in the other category and that way I can check on them periodically and the other group members can do it as well all right and I will go ahead and put on some music I'll be right back and we'll do Q&A [Music] life is a winding road no telling where it goes driving through days and nights won't stop for traffic lights even if is falling down I will keep on searching for my heart you can say oh that's my Maya okay and I am back to give you a context of where things are in my my studio here I've got a camera there hello it's great chatting with you I'm so glad you're here if you haven't subscribed yet please feel free to do so if you like the videos or if you got something out of them useful hit the alert Bell as well so you can learn again from the next ones and my chat screen is right here so if I'm looking down here I'm not ignoring you I'm just gonna take a peek of the chats and I'm just gonna focus on the ones they have my name and bright color so I can actually find them all right Anderson hi Anders welcome is asking have any idea of of CCNA 200-300 on physical labs should I look for or maybe buying one at a time great question list let's discuss that with a whiteboard well this is actually a chalkboard but it'll serve the purpose just as well and let me grab a pen so for a lab I would recommend that you have at least three routers and probably at least two switches and if possible it would be great if these switches could support security features like port security and other security features like dynamic ARP inspection and so when you buy a layer to switch or when you buy a switch and this could actually be a multi-layer switch and on that switch if it's a multi-layer switch you can just do no IP routing boom and it'll act just as a layer to switch no routing capabilities or if you if it's a multi-layer switch you just simply say IP routing and it'll enable IP routing then it can do layer 2 forwarding and you can have multiple SV iced interface switched virtual interfaces like interface VLAN 10 interface VLAN 20 and configure those IP addresses the new routing there as well but from a layer 2 perspective I support that and that what else port security dynamic ARP inspection oh and DHCP snooping would be good too because your dynamic carp inspection is gonna want that information we're getting layer three to layer two mappings that were handed out via IP addresses in DHCP and I've got oh I've got videos in the playlist the master playlist on each one of those so those would be good ones to look for as far as other connectivity I tell you what I wouldn't worry about too much in the old days serial so serial interfaces I say low-speed interfaces like t1 speeds one point five four megabits per second those used to be critical like oh you got to have these especially the old days cuz you had like frame relay and point to multi-point some other options but anymore like routers with t1 interfaces with a back to back cable that supports them 1 DC 1 DT side that's not as critical and so I wouldn't worry about that too much but on the routers they should have it ideally they'd have 2 to 3 gig interfaces and maybe 1 to 2 Fast Ethernet interfaces yeah my brain cells oh I'm writing over myself yeah oh there we go that works oh just a fast e the interfaces that way you can carve out what you want to do and you can have speed comparisons with OSPF versus fast Ethan interfaces and you wanna do the auto cost reference bandwidth with OSPF so it couldn't tell the difference by default routers they think the fastest bandwidth on the planet is 100 megabits per second in OSPF and so unless you change that which we've covered in a previous video on OSPF you wanna change that as well another option is this you a person could just get like four or five multi-layer switches and then on those multiply got thirty five sixty with an enhanced image they're very inexpensive and then what you could do is you could do layer two trunks on those guys any way you wanted to and that would give you a chance to practice all your spanning tree and you could also do inter VLAN routing with creating multiple VLANs and doing switched virtual interfaces and do your logical routing inside of that topology as well or you could also take it interface on a switch a multi-layer switch and say no switch port and that makes it a routed interface so from a routing perspective if this is core one multiplier switch it would just look like that's a router interface on a router right there so the interface on a router could be a no switch port on the interface which is this guy right here or it could be interface VLAN 10 which would then make that logical layer 3 interface which doesn't have doesn't any physical characteristics it's just a logical interface inside so lots of options depends on how you want to carve it out and create it I would suggest before you buy a lot of hardware although it can be fun I would suggest packet tracer because boy it is you know I Jeremy Chara who I work with and I appreciate is he's all about having a physical topology you can plug in and you can see the cables and you can there is value in I mean it feels good it's tangible right some people learn visually some people learn an auditory some are more kinetic where they like to touch and feel and so if you want to get physical gear and physically plug the cables in you can but with things like packet tracer you can build a topology like this if you haven't seen this to be quick you can take you can so down here on the oh oh I forgot to add a layer ok here's new layer so in genus Indian history and packet tracer in the bottom left-hand corner there's options for do you want to router do you want to switch etc so you just click on that and then you drag and drop the devices that you want so maybe you want a multi-layer switch call us which one you want another switch so you call it switch 2 and then you want a router so there's our one you just name whatever you want our two and then you have the ability to connect them all together so you connect them here here maybe you connect that guy there put two in for ether channel that you want to practice with now that takes about 30 seconds after you've done it a couple times just dragging them and then they power on and start configuring versus if you wanted to change your physical topology you have to set your gear up think about it physically cable it move it around so nothing wrong with the physical topology but I would encourage you to start with packet tracer get really good at the configuration and the show commands and then if you want the physical gear bring it in my physical gear is on the other side of this wall and I I plugged it in I plugged it in a couple times recently one was for you dld unidirectional link detection because the emulator couldn't support it in packet tracer and other emulators so I needed it for that says doing a CBT Nuggets on core course topic on spanning tree and detecting loops and I needed that so I use physical here and there's maybe one other exception where it was needed but it's very rare that I would have to break out that physical gear for any CCNA topic including wireless I mean Wireless with wireless let's say we had a wireless controller so in Cisco they call it WL see think of a controller as the brains behind your wireless network and then we have access points will cause ap 1 AP 2 and they're connected into our switches maybe we have AP 3 over here and one of the challenges with wireless is that we need to have coverage so if Bob walking around the network it needs to have good signal for his mobile device or laptop whether that mobile device is anywhere he goes and so what happens is these ApS are getting their instructions from this controller and if we need to change the channels for the frequency ranges those EVPs 8 AP stands for an access point a wireless device that's sending and receiving wireless signals for the benefit of our wireless clients on the Wi-Fi it's a Wi-Fi function so it's wireless controller can communicate with all those coordinate the channels coordinate the strengths identify rogue with the right software involved rogue access points that are showing up and then these access points if Bob is over here and he's associated this access point this access point build a tunnel back to the controller I think of a tunnel like a logical secret path through the network between it and the controller and it takes all those signals and it forwards into the controller and then the controller route them and forward them and process them as that traffic needs to go through the network and so was I getting talk oh yeah so for building this it's like when I did the CCNA wireless a couple years three years ago for CBT Nuggets I literally bought access points and then I I bother I got a software based wireless LAN controller that was running in a virtual machine and then I bridged them all together and it was a pain because to get the physical access points and then to practice what the roaming looks like across access points is tricky in packet tracer this whole topology with the wireless access points and the DHCP server and the server to handle IP addresses in tiles is probably five minutes to set up and cost was zero in dollars so I strongly recommend packet tracer if you're on a budget packet tracer if you're not on a budget package tracer and then if you want to build a gear you want to get some hardware because it's pretty inexpensive on eBay and so forth you can practice and play with that but I would do that as a second measure if you have extra time I'm always about the Pareto principle yeah that way I understand it was he is an Italian economist he talked about the value and he said that about 20% of the activities we do provide 80% of the value and 80% of the activities provide 20% of value I'm all about focusing on the 20% it's going to give us the biggest bang for the buck and packet ratio is one of those things where if you want to learn how to configure and tweak and create networks and route through networks new layer 2 switching through networks and do wireless on networks packet tracer provides a very reduced friction amount to getting to that point so you can do it and it's free where physical is nothing wrong with physical because it just takes a lot longer and next time you boot up a switch go make some coffee because you Paris which I got 35 60 or even the newer ones it's like let's take it off so it powers on goes through power and self-test and then by the time he gets up it could take two to three minutes for that thing to fully boot and it's loud and so if you have a stack of those or several of those that's not a real big benefit okay so as far as building a network please start with packet tracer and then as you want to build a network you could start with I would start with at least two routers and one switch at the beginning point and that we can glue them together when I first in nineteen Oh when I was a young man in night 19 what year was it probably 1999 yeah it's like 20 years ago no 21 years ago yep a long time ago I bought my first routers and this one there was no emulation options so I I went online I found a cuff when I say I went online there wasn't much Google back then either it was pretty much rough so maybe I used not sure how I found it anyway I found a vendor who's selling used routers they were Cisco 4000s is a modular router and I bought three of them it cost with $5,000 for the all three and when I got it's a lot of money a lot of money more money than I at that time I wasn't a CCIE then I didn't make a lot of money then but I thought I'm committed to this so I need the practice and I need to go ahead and do this so I I bought them when they came in they had no Ethernet modules so it was modular so there's the power supply connector a console connector and those and that was it and I was like oh like how am I gonna network these hey I didn't have anything else which I could use a crossover cable if I had a third up ports so I spent several hundred more dollars bought some used modules for it and it was a learning curve and then I got this going on and I built him into a rack and then in 2001 I have intially got my CCIE route switch which I'm grateful for getting that it was a lot of work but totally worth it and then I went on for a CCI security in 2003 and for security I bought more gear so in those days we had to buy gear today please start with packet tracer and then viral viral 2.0 is gonna come out soon and this gave me a lot better than viral window which is Cisco's product it's license for a year 200 bucks and you can just practice practice practice with lots of amazing technologies that would cost tens of thousands of dollars if you had to buy the individual gear okay so let me scroll back up and that was Andrews question what kind of physical labs should I start with I hope I hopefully answer that question for you alright and Norman's saying greetings from the Bermuda Islands nice I've never been there but I'm sure it's amazing okay motels you're very welcome just looking for my name on these oh all the day I think that's how it's pronounced Ola de ji you know how it's pronounced thank you for the question I appreciate you being here you said you don't have a college degree trust me you're oh that's oh that's very kind thank you I appreciate that it's very very kind I'll give you a quick backstory if you want it on me I'll make it short famous last words I was born in 64 I was three I was three at a third out of four children all my brothers and sisters my older brother and sister went to college crushed it my brother works for IBM has worked there for over 30 years for IBM just going through the ranks and he loves it I assume he loves it he's been there for 30 years and I wanted to take the fast track and I learned some really hard lessons on that fast track I thought I just want to go out and I want to be I wanted to be wealthy as a young person so growing up this is probably very common for many people I'm sure I'm not alone in this my father was a principal at why first I started as a teacher in Camarillo captain in Ventura County California and the teacher and at nights and weekends and during the summers I believe he went to graduate school so he get his I'm sorry he went to go get his master's which was required to become a principal so he just ground away kept on studying kept on studying became a principal and then he was a principal for the remainder of his teaching career and he was very prudent with money I mean we never went hungry I never recall ever you know ever we had a house we lived in it was great he protected us is what he did which is you know pretty amazing so on a very limited budget for Texas so growing up I thought what I want to do most of all is I want to make some money a lot of it and then I realized very quickly that there's no shortcuts to doing that and I went into sales for a while I sold insurance I sold cars and I realized that I wasn't good at that and not not without remorse because I found my niche and so I was working at a as a cashier at a hardware type store in Ventura County Ventura California and there was a guy who came in to repair the cash registers and I thought to myself wow this guy looks like he has a nice car I didn't have rust on it and he has a silver briefcase like a James Bond briefcase he looks like he doesn't have a boss I'm sure he did but he was in there working on the stuff and I thought you know I'm not sure what he does or how he got that job but I bet I could do that and so on the TV's true story all the TVs that were across from us from the cashier row there was these commercials for controlled data Institute this is like 1985 9 1984 and I was these commercials would come on and so I called him and I went to LA down to LA was I lived in Simi Valley at the time so I went down to LA and I I got a student loan well alone like it was close to $6,000 as I recall it might have been a little more and I got alone I went to this school for a year and I learned all about electronics and is there their brand new micro computer technology I learned about resistance and capacitive circuits and all these details that I've probably never used but eight months into this one year-long course I got caught mister polite he was the if anyone out there is knows mr. polite who worked at control data Institute in like the mid 80s I think he's passed away by now cuz that's been a long time ago and he was an older gentleman time he was so mean because he cared he was so mean like oh what's this list and he wouldn't give us one inch ever and I thought this guy's such a hard hurt you know hard-nosed why is he being so mean it's because he wanted us to succeed it's the same reason I want you to succeed whether you're a CCNP level or CCI and you're working on something new or you're just getting into CCNA I want you to succeed and so mr. polite would not give us an inch he forced us to learn if we did made mistakes or weren't applying ourselves he was going to call us out on that and about eight months into this one-year course they were see electronic data systems was interviewing that was an old company now bought by HP but it was ross perot's old company back in the day and they were interviewing for candidates for field technicians and they said hey they're interviewing four people our field technicians we'd like you to go and I said hey well I'm not done I got nine ten eleven twelve I have four more months like counting bits for subnet II I've got four more months I'm not done with school yet and they said you don't get it doesn't mr. PI was like you don't get it you're not in school so you can become a master at being as in school you're here getting training so you can apply that skill in a real job and then get more experience on that job and just keep on moving and I thought oh okay I didn't know any I didn't know what I didn't know back then so I interviewed interviews with Nina Nina Martinez went through I some of the details for that or on the youtube my youtube channel my my career so I'll leave him for that so I got this job and started working with electronics and microcomputers let's least to call them pcs with the IBM PC and then the IBM 80 and the IBM 386 which people thought I was gonna take over the world and then local area networks with coax cabling and Novell migrated on to Cisco and then Windows and the story just kept on evolving so where were they going with all that oh no college degree I wanted to take the fast track to success and wealth I'm not I've no no shame in saying that's what I wanted as a young person I realized along the way that the way to actually have a great life is balanced and consistent movement forward that's it I could right now look at so many things and people in my life are in my in the world and say oh I'm so nothing compared to that easy easy but what I do is I just take still I have a whole channel on you know how to be successful and it's basically identifying what the heck you want what you're willing to trade for that meaning I'm going to study so many hours a day or I'm going to do this in this and just keep progressing and enjoy the journey it's not like oh misery misery misery misery then yay success it's got to be a little bit of joy as you're pursuing and seeing measurable results like oh I'm gonna study this topic and I don't know it very well yet and you stay the topic you know well you know I know it a little bit better now and then next time you study it I know a little bit better I'm gonna lab it up and just continue and see that see that growth if we can see that growth in ourselves that's gonna give us the motivation to continue and so I know I'm so fortunate I know there's my wife will be the first one to tell me Keith you like have an overabundance of luck and fortune and just out of just pure dumb luck and it's true I do I know that in addition I think anybody who applies those same concepts of identifying what you want working consistently measuring the results pit you know spot by spot as you go on further and further it's gonna be better than if you did nothing so whether you're lucky or not we can move the needle which is my goal in life these days is to move the needle I want people to change not a whole bunch just a little bit and then in five or six years if you're just starting the CCNA journey with me in five or six years when you've got your ccnp and you've got some experience and maybe you're working on or you have a CCIE or two or you're working with other vendors like checkpoint or Palo Alto or other vendors with great products as well I I would love nothing more than to meet you or contact you online and have you say Keith oh my gosh thanks for starting out this career for me or thanks for helping me along the way that's it that's my home motivation is I would love to help other people just move the needle a little bit and everybody in this channel can do that with me all right off my soapbox measurable move okay so college is great I don't I if I had to do it again I probably still would not go to college just because I I was a little bit rebellious as a young person who had an inferiority complex which actually carries on today a little bit so I'm just willing to work a little bit harder than someone else who may not have that motivation and that makes all the difference okay so that was paste in that one question branch much no yes all right um Omar's asking hi Keith can you give an example of vlsm but start from low to high 4/24 subnet and get the tool and links from this last 30 here's what one more great question in my entire career I've always done submitting custom something and planning them out well now I use calculators right because there's no reason that you do it manually unless you're in a certification environment but I've always started off with the biggest subnets first working down so here's my main request to you if you would like to do the custom sub nothing like we did in the previous subnet Saturday and work from low to high go ahead knock yourself because the process is going to be the same and I just never do it from high to low I believe it could be done and that question last week made me think about that but I always do a higher to high low so Omar if you would if you want to post that as a request in the discord channel let's go ahead and do it and we can have people get feedback on it and put in their results and if you're going to start off with the slowest you this the tiniest you start off with this last 30 s take that range which would be like dot 0 through dot 3 and then the next subnet would be dot 4 based on that slash 30 mask and then you'd do it again and then the next mask or the next mask based on how many hosts you need so I believe the process would be the same and I would encourage you to do that in the discord channel so we can all see it alright nicholas welcome Nicolas is asking about the switches and routers features you're talking about for the CC lab could you tell which chassis devices versions would support those features oh great question it really depends on the iOS that's running the software that's running on those switches and routers so if you go to Cisco site I haven't done this in the last six months but if you get a cisco site you look at the feature set for which iOS features support which functions then you can see all this which with this image supports dynamic arp inspection dhcp snooping so if you're buying it on ebay or somewhere else you can look at the output see what version it is then go to Cisco's website and search for that version and feature set and there used to be a really concise page I don't have the URL for it perhaps something that yeah and they're in the discord or here can find it that allowed you to go to that version of iOS and then or a feature set navigator I think it was called where you could put in the features and it would tell you what versions of software habit usually enterprise it's gonna have most everything but I would also just verify that and that way when you're searching on for kits or hardware on eBay or where we're gonna buy it you could take each version of iOS verify what features exist and then buy it or not buy it based on if those features exist because if you buy a Cisco router on eBay it's not through an authorized reseller usually and as a result you know you're not gonna get support from tak Technical Assistance Center Francisco and you're also not gonna have the rights to download updated software for that device so those are all challenges that come with you don't get the right software on the iOS device but a really great question I appreciate the question pulse Paul CCNA is asking is there a controller in packet tracer there is a wireless LAN controller in packet tracer I know because I included it in at least one of my CCNA sorry yeah yeah and at least one of my CCNA content at CBT Nuggets I actually lapped it up I thought to myself okay I need to teach wireless LAN and controller and associated with access points and getting a client connected having a DHCP server what is the most effective way that a learner could realistically do this and the answer was packet tracer so I demoed it in packet tracer and I also have at CBT I have a whole like six seven videos in a packet tracer section that walks through how to set it up which is pretty straightforward just go to netacad comm download it get a license for it free and then start dragging those devices out to the network topology and go to the CLI tab and just start working with them so thank you for that question policy and it's Paul's CCNA alright scrolling down to yeah here is mah IR so my hair is asking are stating for viral which is the Cisco product that's licensed for one year for two hundred dollars for the full year you still need a good server to run on to run that on that is true so whether you have a dedicated piece of hardware that can run the free ESXi from VMware or if you have a PC that has VMware Workstation or if you have a Macintosh with VMware fusion you're gonna need some pretty good hardware to run that so I I just ran that actually yesterday I hadn't touched it in a while download I have a license for it so I installed it configured it and version 1.6 which is the current flavor as of today it's it's not too straightforward to get the whole thing going and my anticipation is that with version 2.0 viral which I hope to be released anytime now from Cisco I don't know if they're gonna upgrade me or if I buy another license but either way hopefully it'll be more straightforward and less friction for a person to get into it but either way currently you definitely need some horsepower to run it I probably at least 16 gigs of ram and if you had an i7 processor that wouldn't hurt although you could probably do it on less but you're gonna need some RAM and CPU to make that happen great comment Thank You mayor all right he's also saying mah IR is also saying I am following you since 2011 when I was with I&E I still love your security videos you made for I&E well thank you I had a great time and I Annie that's internetwork expert and they got that was the Brian's Brian began and Brian Dennis who are the two chief architects there Brian Magana still with them they got purchased or enveloped in the larger company I've got several friends that work there I like guiity if you're interested in ccae training I have zero reservations about sending people there they also do some CCNA level stuff as well so thank you for that I'm glad to have a friend from 9 years ago still with me and now helping out in the channel fantastic ok rage encrypt I was asking hi Keith I'd like to know what is the tiebreaker in STP spanning tree protocol if there is one switch with two switches connected to another switch but all four switch IDs are the same great so that's a lot to unpack there but let me tell you how it works and then it'll answer that question I believe the first question about who's going to be a designated port or route let's start with route ports if I'm on an on STP route let me go ahead and bring this up and we'll draw it out not only will that give us a chance to draw it out it'll give me a chance to think and also to present this appropriately and let me bring up another layer and let me get some pen out here okay so actually see if I can look at your question here all right so it's too much for me to unpack in the comment right there raging crypto but let me just let's go ahead make a scenario like this and we'll put a couple there a couple there a couple there and we'll call a switch one two and three and let's say it switch three is the route so this is a spanning tree question everybody if you haven't yet joined us for our spending free discussions we have some pretty fun ones and very very thorough ones here in the playlist the master playlist on this channel so take a look at those if you want so let's imagine that switch 3 is the route B becomes the route he or she becomes the route because it has the lowest bridge ID among one two and three and the bridge ID has three parts it is the bit priority and the base MAC address which is not the MAC address on an interface it's the base MAC address on the platform as it ships from Cisco plus the VLAN ID all right so switch 3 went 1 he's super happy he's the route and let's couldn't put that in yellow congratulations you are the route all right now the question is switch 1 and switch 2 are not the route and so they need to identify their route ports so route ports only exist in spanning tree on non route bridges so route ports how do they decide switch 1 and switch two how do these hi individually on their own which is the report and the answer is lowest cost to route so let's imagine all these links are the same whether they're fast ethernet or they're all gigabit let's imagine they're all the same and this focus on switch 1 for a second switch 1 says ok it's the lowest cost to get to the root and it says to itself self says switch 1 both my interfaces I'll call this interface 1 actually interface a mmm I will use 1 actually to make this very clear I will use interface 6 and 7 and over here on switch 3 the route I will use 10 and 4 that way we can make this very clear how the decision process works so switch 1 says what's my lowest cost to get to the root and it says well it's the same cost going through interface six and interface 7 same exact cost so that one's out the next one is the advertised bridge ID so in this case the root bridge has a bridge ID as this guy he's advertising it down both ports so if switch 1 was connected to multiple switches and they all had good possible paths to the root it would say oh if it's a tie like do I go through switch 9 or switch 10 if both switches have equal cost from from our once which ones perspective it would choose the one that has the lowest are the lowest bridge ID but in this case both these links that are being out there are going to us which one they are both advertising the same exact bridge ID so the bridge ID is the same for interface 6 interface 7 so the next thing that switch 1 is going to consider as it tries to decide which route port to use is lower I'll say lowest ello WEF t advertised it make sure my face isn't on there yeah my face is on there whole thing lowest advertised port priority and so let's imagine that now we're talking bout the route advertising here and here if the switch has a default priority which i think is 128 by default on each of its ports its advertising a priority of 128 down both ports so switch ones like disappoint it's like well these are both the same cost six and seven the advertise bridge ID coming down from switch three is the same it's the same bridge ID of the upstream switch which is the route in this case and the priority is the same once when he ate here once when he ate here now what then is the lowest advertised port ID and I will circle there yeah so the lowest ever times port ID so basically switch three is advertising a port idea ten on this port and a port ID of four on this port its advertising those and that's why I have this keyword here advertised port ID and just like golf spanning tree is lower is better and that way switch one for its route port would choose port seven because that's where heard the lowest advertised port ID based on all the other factors being equal they were both the same cost they are both coming from coming from the same bridge ID so there wasn't the lower one there they were both advertising the same port priority and the tiebreaker was the lowest advertised port ID so port seven would be used port six would be in a blocking state or in spanning tree officially they would call that discarding state but it shows up his blocking with a show command and it would show up as an alternate port meeting if that primary port is not available anymore that alternate port can go ahead and start forwarding if we're using rapid spanning tree if you're using traditional spanning tree and you lose a port you can use uplink fast that would give us the same benefit and that is the answer to that question alright thanks for that question by the way let me see if I can screw up and see where I was give me one more mo okay Wow way up there all right so moving forward okay flux flux polarity which is a great handle by the way a Suzuki thanks for all your video tutorials question I'm using a laptop it's connected to the internet using Wi-Fi can I use Wi-Fi internet to act as an ISP in packet tracer that's a great question flux I don't know I think there are options for integrating your packet tracer topology with other packet tracer topologies so I have not experimented with that yet if you want to join discord and put that as a question if somebody else doesn't answer that and you can post it there you can also do an at Keith for me and that will get my attention I can look into it as well so I don't know the answer for that but I am interested in looking into it great question all right Daniel's Daniel's saying that there are some limitations with packet tracer we just explode on discord IP access let's tree resequencing okay well if again in discord if there's thing if there's like a question-and-answer and you want me to jump in to any of those discussions and give my two cents I'd be happy to do it just do an act keith barker and say hey here's this discussion in that same channel and I will I will get some attention on it I love it when people are chatting about how things work packet tracer is a simulator it's great for most of the basics that we would need for CCNA it's not perfect doesn't have every single possible command but it's more than enough to really learn Cisco Networking okay all right Norman has a question about CCNP encore really quickly 350 401 what I would do if you're considering taking any exam just download the blueprint look at it go through each item and say to yourself how well do I know this on a scale of 1 to 5 and if it's a 5 great if it's a 1 I would brush up on that topic before you go take the exam to make sure you're good at it or good enough to pass an exam on it and I would say if you're like a 3 or less on any topics in the blueprint especially one that says configure or verify I would probably brush up on that before you take the exam so I haven't seen the encore exam yet oh by the way oh yeah yeah I'm going to be sitting the CCNA exam probably in about a month and a half and the feedback I've gotten on it is that it's it's incredibly tiring it's a hundred plus questions like 105 ish or something haven't taken the exam yet but the feedback I got I said I've got a look they just open the kimono here for a moment I've seen a lot of videos regarding people on their experience now there's an NDA non-disclosure agreement that you're not allowed to talk about exact questions great so we should all abide by that and that's part of the rules in this court as well don't reveal anything that cisco doesn't want you to reveal but if there's a topic a blueprint item and you want more information on that blueprint item or we should focus on that blueprint item that's fair game so there was some it's great I will always tell you the truth on this channel about the technology how it works my goal is to make sure you're comfortable with it encourage you motivate you to get hands-on practice and and and learn the technology of CCNA and then keep on those skills keep keep them moving I saw some videos that were very very great about the exam about hey this this section of the blueprint really need to know it this section kind of casually and some ideas about that fantastic and I saw other I saw other people and these are I will not really real any names ice other people that were justifying something that probably is not in the exam but that they have content or training for that they wanted to justify why they were still training on it there may be a technology or something that's casually mentioned or not mentioned all in the new blueprint or the new exam so I'm grateful for I'm grateful for people who are willing to share their experiences and share within the limits of the NDA and their opportunities of of improving for the exam and my goal is and they've got a lot new ideas by the way based on watching all these videos of new topics that I thought oh you know what that would be great for a live stream oh no you know what that would be great for a live stream and so I've got maybe 20 so that could be I do streams on Wednesday afternoon Pacific time so get out your world clocks Wednesday afternoon at 4 p.m. subnet Saturdays is Saturdays at 11 a.m. and then sudden CCNA Sunday's is also 11 a.m. on Sundays and so I've got maybe 20 plus topics that I want to add for CCNA that we can do on Wednesdays and Sundays and then for subnetting I think probably within two or three more weeks of one a week we'll cover most of the core topics where anybody could go to subnet Saturday and just say Oh got it got it got it got it and go down the list and and be very comfortable subnetting so regarding challenging an exam make sure you look at the blueprint and if you feel like you're comfortable two concepts I would say go for it okay Edie you're welcome thank you very much for that comment and my harrassing I can say that I did my CCA just because your videos motivated me and taught me the technology in the easiest way uh-huh that means a lot thank you that's awesome well way to come back and support other people on their journey in CCNA which is the folks of this channel I really appreciate that alright M I am does EXI host connected to real switch okay so ESXi is a free if you buy a standalone version from VMware that's their standalone hypervisor and if you're connecting it to a real switch a physical select the virtual to physical it would be you could do trunking to that switch so on the switch side you say trunking and then on the VMware side in the virtual switch you'd specify that you're supporting multiple VLANs and that way you could actually carry multiple VLANs between the inside world with the EXI host to the outside world I if our CCNA I wouldn't expect people to have to do that but that's how I would do it if I wanted to carry multiple VLANs out or if you wanted to have everything just in that virtual environment you might have one interface or one VLAN that goes out to the outside world and then all the other VLANs are mapped internally that would work too and I am great to have you here it's your your words and your ideas that help me change my music up a few times and I also appreciate all the comments okay okay great great great great Angela's asking about wireless topics in CCNA which is the difference between great I am going to hang on to CCNA Wireless questions and I would like to do a few live streams on that to go ahead and elaborate make sure you're comfortable with controllers access points associations and the wireless technology you can use such as the being the encryption the security with wpa wpa2 douvier to put wpa2 personal also Angelo if you would if you're on discord which I'd love you to be if you go ahead and post that in a suggestion for a video and that way I won't forget it like hey let's do a video on this or a livestream on this okay Daniel thanks Chinese vlsm from small to large if you post that in discord I will I will actually do the exercise and post my results I just because I've just not done it and I don't think I've ever done it I don't think I've ever done blsm I'm starting with low going to high and that's probably why I'm not a big promotion a promoter of it and if you're doing it with a piece of paper or cut of vlsm calculator starting from large to small it's gonna make sure you have enough room to begin with and it's always been a the way I've done it is start with large your larger subnet some work smaller okay ipv6 addressing John Kennedy you my friend are in for a treat that is coming so ipv6 addressing was based on the feedback I've heard and again I haven't taken the exam yet but there is a pretty hefty section for ipv6 and let me share with you this it's like Keith what is this this is a chalkboard okay that's imagine we have routers no router one router to router three make sure I'm mike is over here and they are connected and the actual connectivity maybe we have a slow link and a fast link let me change this yeah so let's imagine this is fast ethernet and this is gigabit and this is let's call it slow that's for serial slow and if it's ipv6 and we have networks hanging off here so we have network a and network b and network c and there's no dynamic routing protocols so for CCNA they cover OSPF version 2 which is OSPF for ipv4 but on the blueprint it doesn't have anything about OSPF version 3 but it does have quite a bit on the blueprint about ipv6 and ipv6 routing let me grab the blueprint all right thanks for waiting so in Section 11.8 sorry for the paper noise there yeah so the section one of the blueprint from Cisco 1.8 says configure and verify ipv6 addressing and prefix which is the network portion and then 1.9 is compare I P v6 address types global unique local link local and caste multicast modified eui-64 which i intend to and cover a lot of that in our sub in our subsequent videos here as prizes channel also our CBT Nuggets course totally crushes all this by the way everything on I talked I saw Jeremy's video as well and he went and took the exam want to make sure that our CBT Nuggets content was very was thorough enough to master the content to the level we could pass the test as well and he said thumbs up it's got everything that's required although he's it was a taxing exam and then going down to 1.11 is our Wireless and going down to Section three more ipv6 here we have section 3 which includes yeah 3.3 configure and verify ipv4 and ipv6 static routing and I can tell you that the course they did at CBT for CCNA we cover it extensively and so I'm going to include also here on YouTube will have our instructor hours like live live stream will help will focus on ipv6 but maybe a situation like this where IP all these networks are ipv6 and they want you to put in static routes that would allow full connectivity between networks a B and C using the most optimal paths so for our one to go to our so for network A to B and I would use a different color here let me back that off so from Network a to be I'll I need lighter color still playing with my pins thanks for patience so from A to B the path would be r1 r3 r2 because that's going to be the faster path we want to avoid that 1.54 megabit link if that's the case and then from so basically the concept would be full connectivity between a and B a and I didn't put C over here between a and C a and B B and C we want to implement static routing so we're using the optimal path and the only way a person could do that is to have some practice in doing it so you'd have to plan it out first like okay what are what is our ones decision going to be to get to network B and that static route should go this way I'm just saying from this topology and for a router one to get to router C either out should go this way and that's it from router HC both of those networks then from router 3 to get to a and B it would go this way and this way and then for r2 to get to those two networks it would be this way and this way avoiding again that slow link and if they wanted to back up route in case this link goes away then we could have a floating static route for ipv6 the concept is the same for ipv4 and a few v6 a floating static route that would go over this link if needed now that would be based on their requirements they didn't say anything about needing that the answer to this scenario with ipv6 is understanding how routing works how to look at the routing table and then how to configure static routes for ipv6 which my understanding is more than fair game for that exam and that's why I got like 20 new ideas of things we had additionally cover so that that thing I just did was just out of my head and we'll build some labs like that and I'm also thinking about building packet tracer so that as I as we do a few of these like any of these demos that I've done through these series usually there's demos on implementing commands they can be done in packet tracer and so I might just sprinkle in some packet tracer from the ground up so that you can get more comfortable with using it like in this topology with three routers like pb6 drag drag drag three routers Auto connect to a boom boom boom and then maybe put a PC on each subnet put in an ipv6 address the addressing part might take a few moments but that's that's a great way to get practice with all that so thanks for that question and that was from John so thanks for that request John and let's see here Wilton is asking hi Keith and the community what is the use of sniffers and how is it configured please great great question so in a production environment there's lots of ways let's back up a little bit let's use this device as an example this is a little a si but all these ports can be configured as switch ports actually they are these are a layer to switch ports on this little a si and we're carve-out VLANs on the inside that's a whole nother story so if we wanted to eavesdrop on the network I call it a jump ring with sniff we would say to the device see this port right here take everything on this port and redirect it out this port and then on this port we could have a device with a protocol analyzer that's capturing the packets like Wireshark which is free easy to Google for Wireshark it's a free download and we could have a PC connected with Wireshark on that port just telling it to listen and eavesdrop on the traffic and it would capture all the traffic that that computer is now sending or receiving on that port also that's called spam in a switched environment it's called spam meaning switched port analyzer there's also the ability to tell a switch that hey take all the traffic that's going into or out of or both VLAN 50 and copy it to that port where that protocol analyzer is hanging off of there that computer with Wireshark running and that will allow us to analyze that traffic so like I'll tell you what I've done for a long time is I grew up after like when gns3 was first coming out as like version point zero eight or 0.8 or something early I thought to myself this is the best thing ever because I don't have to buy these racks and racks of switches and devices I can use genus 3 and even though it's not perfect at that time it's gotten a lot better since I don't have to have all that physical gear I also learned that in packet that in gns3 along with other simulators you can actually integrate the capturing of packets so you can have router 1 and router 2 connected over either a crossover cable or both connected to a switch you can just right-click in genus three right click on that link and say capture packets if you installed Wireshark which is free and Wireshark on that same machine running genus 3 would capture all the traffic on that link and then we could analyze it and look at it and search through the packets and see what's happening with it so regarding the use of sniffers and how its configured if you do it in a physical environment on a switch it's going to involve spam on a Cisco environments switched port analyzer or you're copying all the traffic from either a VLAN a report over to the port where your computer is that's running Wireshark or you can also see this thing called remote spam where it takes the traffic off one switch and ships it over to another switch over to a port so you can analyze the traffic but they the easiest way if gns3 is running the easiest way in genus 3 is just to right click and it automatically has the option for start captioning packets with Wireshark and that's if you have Wireshark installed I'm gonna hit this button which turns on my fan it's getting a little warm here in Vegas it is what month is it's March March 7th and 2020 and starting to get warm outside all right so thanks for that question that was from Wilton thank you oh and John Kennedy just confirming that ipv6 questions are throughout the practice exams good and it's based on the feedback I've had ipv6 is gonna be more heavily hit in the past like with old CCNA stuffs it was touched on like hinted at and now it's it's gonna have a fair shake based on the objectives in the blueprint okay dan is asking can we get one more example for the reverse engineering Dan yes Dan if you would like to I'm going to answer a few more questions if you'd like to post give me an IP address any IP address with a mask and let's make it not a clean octet like something other than a slash 8 or s slash 16 or slash 24 something with the non eight sixteen twenty-four bit boundary so we have something to play with and then also make sure that the last octet for the computer is odd and that will make sure we have at least one host bit on in the host address because that's one of the rules for IP addressing the host portion the host bits at the very end of the IP address they can't be all on that's the broadcast address and they can't be all off that's the network address so they have to be at least one bit on and at least one bit off in those host bits so Dan if you're up for it if you're still around go ahead and do an ad keys give me an IP address with those considerations nan even our non clean octet boundary and an odd last octet with the odd number in the very last position and we'll do one more yeah love to okay moving on all right so my hair is it looks like a statement thank you for that and let's see here moving down where my name is showing up and he's saying you have the Oh an amazing skill to not be shy when you're alive teaching other people without messing up thank you I appreciate that I mean I'm so human I'm about as human as everybody else in fact I'm sure I'm sure that's it I'm 100% sure that's the case and I have practiced a few things over the years so it gives me a little bit of a comfort level I feel pretty comfortable that with whatever happens based on the concepts I'm teaching that we can just follow those through and they'll be fine too thank you for that okay all right we talked about the sniffers yeah my hair is asking how do we how do we practice DNA the DNA Cisco's DNA Center that's a bit tricky at the CCNA level it's mostly about understanding being aware that that exists and not really configuring it so as we go forward my hair I'll give us and thought if you would put that in discord as a request or suggestion and let me find out how somebody who doesn't have oh I know I know so for DNA there is cisco has something called d cloud which is free and they also have something called the def net sandbox and both of those options have some features regarding DNA center so that would be one way but let me I will include some of that coming up in live streams and also give people some clean paths on how they can practice it without having to buy any kind of serious hardware to get there okay okay great great great yes Andy says that I'm near the 100k subs milestone yes I'm it's only taking me since 2009 I believe my first video is 2009 and I think it's now growing at about 2,500 a month so that's you by the way so I've got a lot of old videos out there the technology doesn't change so the technology is still good and I looked at one on reverse engineering an IP address and I have an old one from like 2013 I think I look a lot different I feel a lot different than I sound a lot different but same technology so if you want check out that video as well but thank you very much on recognizing that so I imagine by the end of April 2020 I will be at 100k and financially for me that doesn't mean anything but emotionally as far as helping more people get their CCNA and also the people who have their CC or coming back to help other people that means a lot I really enjoy the mark the ability to make a difference and we're doing it right here right now you and I everybody in this room thank you okay alright am I am if you'd put that request in the discord that'd be great we're getting a LAN link redundancy on a firewall or layer 3 switch and ok how do i raging crypto saying hey how do I find Keith on discord if one of the moderators or somebody could help with that I have this icon that says og of IT so if you did a search for og IT underscore Keith I think it is or you do a search for Keith on the discord channel you'll that should find me and I if you don't you can post that as a general question and one of the moderators will help you find me ok that was a couple of questions from people and looking for any last questions regarding sniffing can you integrate PF sense in a Cisco environment pfsense is a free for a certain quantity I don't they have a corporate version of it but PFC a very detailed firewall it has lots of options and can you integrate that in a Cisco environment the answer is yes you can put pfSense in any environment and it would do the functions that pfSense this firewall has for it so a lot of times in most environments you have lots of different gear like there's a lot of Cisco shops that don't use fire power for their next-generation firewalls they use Palo Alto or sometimes the company from Israel why am I forgetting them Check Point yeah as their solutions and any solutions gonna be fine as long as it works and functions so we're often gonna find mixed environments with different gear and Dan I don't see a follow up question with an IP address I think we had a question earlier one more example for reverse engineering if you still wanna see that Dan throw me an IP address before we finish up and would be happy to do it all right flux flux polarity is saying you just want to thank you for pointing out the power of block size I learned to understand subnetting easier thanks Keith you're very very welcome and the reason I we Circle it we did our video on block size and we circle it like a square that last bit of the mass that's on that's also that's also the block of addresses that it's representing a block of addresses that we can use in that subnet so you're very very welcome all right I don't see another I don't see another example request from Dan so he may be gone okay so if you have other requests the things you'd like to see or things like to work through we can certainly do that in the discord server it is let's see it's almost 1:00 o'clock Pacific time 1250 says 11:00 12:00 almost a two-hour stream but I've had a lot of fun so we covered most of the meet of the content which was how do reverse engineer what subnet a client song based on its IP address and that took the first hour and then we spent last hour here focusing on just some QA alright thank you everybody for joining me our next live stream as little heads-up is tomorrow it's for CCNA Sunday I've been teaching for a long time I've worked in the industry for a long time I love it I love it's like tinker toys putting all these pieces and parts together and then as we apply Software Defined Networking and Network automation to all of it we're still using a lot of those technologies that we have to understand how they work so everything we're learning there's nothing that I think I will never use that ever again it's not like me it in my control data institute days in the 90s are the 80s rather whereas learning to read the resistance codes on a resistor if the color codes and determine oh that's a xx resistor which I've never used all of this stuff that we're learning regarding Cisco and reverse engineering and IP address and how to configure a router and reading a routing table and layer 2 switching and trunking and VLANs all the rest that's all going to be serving us for the rest of our IT careers because if we do start automating all of it or portions of it with automation we're still going out to beware of those scripts that are being pushed down or how the controllers talking to those devices so the concepts don't go away oh great great do bonds asking can you please explain what is this discord so about four weeks I'm so behind the scenes I'm learning I'm such a baby about four or five weeks ago somebody chatted to me and said in the in the live stream they said and if this is you thank you for the recommendation they said hey why don't you set up a discord server and I thought to myself I've heard of the word discord I know some people have a discord server I don't know what it is and so I started googling and did some research and what a discord server is it's free you join it and you set up yourself a handle whatever you like to call yourself and there's discord servers for different topics from different people so you might have a like a twitch gamer who strains twitch his his his or her favorite game several times a week and they'll have a discord server where people of fans can jump in the ask questions talk with each other make requests kind of like a community where we can hang out so with the live stream we have this chat we have here which is fairly temporary as long as the live stream is going and then there's chat messages below our discussion messages that we can ask things below but that's also kind of static not too interactive and I do go back through this I look at those a couple times a week but discord is like a separate think of it like a way for this community everybody who's working on CCNA or everybody wants to come back and help others who are working on CCNA where we can all get together and chat about ideas or questions if you have require requests for videos to be a great place simply a hit place to hang out when you're available now we have like 10 10 or 12 moderators who volunteered to help which I'm so grateful for and all I ask of everybody is to check out the rules when you go in there's a rules channel you just look at it and agree to the rules and if you're okay with that which includes what the rules are just go ahead and join and and ask questions so if you have a question regarding MPLS traffic engineering that would go in the other section even a question about spanning tree regarding CCNA like the ones we covered today you put it in there's lots of people who are gonna be answering that and feeding it back and giving their opinions and the answers and if you ever have a qualifying question the moderators are so great does just say hey Keith check this out or answer this if you would jump in or you can do it to everybody on the channel on the disk or server which would give us free can go ahead and ask questions they can you can that's the best way to contact me by the way just doing at Keith's I think I don't at Keith myself but on the discard server I think I'm pretty easy to find and if you just do an at and either og of IT or at Keith's you think either one of those is gonna pick me from a list and then you can send me a friend invite for the discard server or you could just send me a message and every time I jump on those were highlighted for me so I can see him so that's what this course server is new to me a chuck Keith who I work with at CBT Nuggets I think he's he's got thousands of people on his discord server helping talking all these good things and I'm just new to the game Oh Dan has an IP address rockin so thank you Dan for jumping in let's do one more reverse engineering if you need the bolt I totally get it you want to hang out here and listen to the sound of my voice as we do one more reverse engineering I'd love to have you stay either way it'll be recorded if you come back you can look at it later that's great let's go to the topology and let me clear off I bring the mic over and let's bring up another layer okay well damn thank you very much for that request I'm going to look at that request so I can make sure I see what it is all right let's jot it down right here we have a PC this isn't just any PC let me bring my face as well this is Dan's PC because this is his question Dan's PC that could represent a mobile device on a wireless network it could represent a Linux box a Kali Linux box Ubuntu it can represent an Apple computer it could represent a PC it can represent a printer maybe even some device that's on a network that has this IP address courtesy of Dan and that IP address is 10.30 3.73 dot 213 oh I think I'm in love with this address with uh slash twenty nine then you just double check that 10.33 does 73 to 13/2 so I'll keep my face close to the mic so I can be heard all right well I think there are some rules to this game of what network is this that's the game we're playing the game is called what's the network and I'll put net ID so think of the net ID like the street name let's three does this that Dan's PC is connected to and the first rule is get the block size and the block size is based on the mask so we'll go ahead and put our values here 1 2 4 8 16 32 64 128 and 1 2 3 4 5 6 7 8 in the heat of battle make sure you have eight positions there if you skipped money I like sevens like wait wait wait I so that's 8 and this last 29 means that the first 3 octets the first 3 sections of that mask are all on so we're gonna focus this is the third octet going that way and is the fourth octet or fourth byte of data after that period right here going this way so let's put in the mask in binary so we have 24 up to this point and we're going for 29 so it's very 5 26 27 28 29 that is the dividing line right there boom between network on the left and host bits on the right so that's net that's host and so far so good and then our question here is block size so we'll go ahead and we will put a block around the block size which equals 8 so let me check my work take 5 to 6 percent rate to 9 that's the least significant bit in this last octet this is the mask and our block size is 8 all right we are off to the races so now that we have that block size well we could do is we could take 10 33 77 1033 73 0 and just add 8 and add 8 and at 8 and add 8 and at 8 and if we had like this just like a mile of room we could list all those possible subnets because 1 2 3 4 5 if we have well we don't know where we started with the mask but we have a lot of possible subnets and if we wanted to list all of them it would take a long time so the shortcut is 2 we are going to take the octet we're talking about this last octet right here where that mask is splitting and dividing that IP address in that last octet the customers octet and divide that by the block size and we'll do that math over here so the block size is 8 and the customers last octet here is 213 and so 8 goes into 21 2 times because if it went if we tried 8 times 3 is 24 it's too high so 8 goes into 21 2 times that's 16 doing the math that I learned in school and because I don't have a college education it was probably somewhere in elementary school that I learned this still going strong after all these years and I would take the remain so I would borrow the one this is so if they don't teach math like this Tim people or maths if you're in Europe this is the way I learned it so 6 and six is 12 that would make it nine that'd be 15 sorry six and six is 12 that make it five so sixteen yeah and the way you can check that this number Plus this one if it equals the top number you're in good shape so that would be oh my gosh my brain okay so one minus one is zero so the remainder here is five so eight times two is sixteen the room is five we bring down the next character of three and then the question is how many times does 8 go into 53 and it doesn't go in let's see here 6 times 8 is 48 I'm gonna go for that I'd say 6 times 48 and then the remainder is 5 is that right 48 4 9 50 1 2 3 yeah so the remainder is 5 if my math is right and this one wants to double check me on that that's great and then we'd have a remainder we do it again but we don't care about anything after this point so then the third step is you take the result which is 26 this result right here and we multiply that by the block size of 8 so let's do that 26 times 8 6 times 8 is 48 8 times 2 is 16 17 18 19 20 208 so that would mean we're gonna take this down and the fourth step is to plug it in plug in that number in that last octet so this would be network 10.30 3.73 dot 208 with a / 29 bit mask and the next the next subnet would be 8 more because that's our block size so the next seven that would be 216 that mean our range here would be dot 209 through 214 with the broadcast address for network a being 215 and the next subnet being 216 now I have reason to believe that that's true yeah I do I do and what's one way we could test that I don't have a router up at the moment but do you know I do have I've got a computer right in front of me I'm on it so let me let me go to network connections and I will make sure we can all see this this is my computer I'm on I'm using private RFC 1918 addresses here in the studio so won't be too much of a problem change adapter options here's this interface right here that I'm on it's it says kill KBG Wi-Fi but it's actually a wired connection that's Ethernet and let me hmm I don't want to blow out oh yes let's play with this one right here properties yeah yeah so in VMware Workstation it's got control of this interface but we can use it here as well minimize couple ease hold on I need the information back here so if this is the 208 Network I'm going to shut that down on a separate piece of paper so 10.30 3.73 208 and the valid host range is dot 209 through 214 and the mask is a slash 29 great which would be 248 in dotted decimal for that last octet that'd be 128 plus 64 plus 32 plus 16 which is 240 plus 8 more be 248 I just want to be able to put that IP address on an interface on this computer and then we can actually look at the routing table and it will tell us whether or not what the network is so let me go back here and I've got a window for that there we go so I'm gonna use a specific IP address and let's go ahead and pick 10.30 3.73 dot - OH let's use the range is let's use 212 or let's use 213 that's in that range 213 and here's the mask and the reason this is relevant because IP subnetting works on all the devices whether it's linux windows routers multi-layer switches with via an interface VLANs via their interfaces and we'll go ahead put the mask of 255 255 255 dot - 48 which is those additional bits in that last octet yeah that sounds right and we'll click on OK and ok and now to see the results of that let's do this will bring up a command prompt this is PowerShell but it'll work and let's do a route print so route print from a Windows machine is showing the routing table on this computer and then I need to find the 10.33 there it is see that right there this says this computer believes that it is on the 10.33 and of is that readable it's you small 10.30 3.73 208 Network there's our mask and the interface IP address is about 213 so when we put that interface IP address on from an IP address on that subnet from a routing perspective this computer says hey I'm directly connected to 10.30 3.73 208 and it'll be the same thing on a router cisco router or a multi-layer switch if you said IP address is dot 213 with that mask and then you - show IP route it would say hey I'm directly connected to the 10.30 3.73 208 Network so thanks for the and then when I go back to my VMware Workstation environment it's gonna totally bark at me because the the networks are managed there through the VMware Workstation utility which is I'm what I'm using for a virtual environment to support my viral okay so I think that was all due to coming back here that was all due to Dan's request Dan thank you for that a great way to finish off and so in the back of my mind I'm thinking is all my math right yeah I think it is I think it isn't we verified that we verified it the toroid subnet on paper and then we applied an IP address from that range on a computer and then we did a show a route print on that Windows machine and it showed it was thought it was connected directly to that 208 subnet so thanks for the opportunity to do that one more I would encourage you yeah great feedback people fantastic I would encourage you to practice that and and make sure you're comfortable with that and we're gonna continue our discussion with subnet Saturdays with I see the next one I think is gonna I think we're due for summarization that's what I'm thinking right now so summarization of taking many routes and instead of super subnetting making the mask longer we can do summarization also called super netting to have one route represent a whole family or whole group of networks which can make our routing table smaller I mean why bother memorizing that there's 42 routes out this interface if I can summarize those with one or two routes that I cover that entire address range so all that's coming up and go trek 65 is asking for a link for the server the discourse server and I happen to have that right here let me bring it up thanks for the request I can copy and paste with the best of them and paste okay Dan's asking about that last scenario which is a great question and I'm gonna just go ahead and read that question make sure you got it let's eat Dan's asking Eric just saying thank you I understand but now we're from the 214 so from this point we have the subnet of two wait the range is 209 through 214 the next subnet 216 and the next that is the next subnet so if we want to know the range for the 216 subnet we'd have the blocks if we're doing the same mask every time so we're not doing verbal ink now I'm asking we put on that next block size the next two sixteen plus eight more would be 224 I believe yep I just doing the math in my head and then that means the range for that next subnet would be 217 through to 22 next seven that's 224 and we just continue that for using the same mask add the block size that's your next subnet that's the range and Bob's your uncle as they say somewhere I'm not sure where Bob's my dad not my uncle all right let me see if there's any final ask questions in the queue and do you I know the muffin man by chance mash I do not I would like to if he's willing have enjoined the discard server so I can get to know him all right that's it see you tomorrow if you can join us for the CCNA Sunday we're taking a look at NAT I've heard many people discuss NAT and sometimes this is a little negative which I don't like going down that road very often but sometimes as trainers over the years we get a topic it's like oh I just have to survive that part in a live class I have to survive that part and then we'll go on to something better and sometimes trainers don't do it's in the absolute best interest of the learner which is this I'm just telling you if if I train err is teaching a concept it is in the best interest of everybody involved to study that concept make sure they understand it find an analogy or a metaphor that is correct that way we can take something that we know like a VLAN is like a room full of people you shout everybody here is in that same room that's what a VLAN is a layer to broadcast I mean let's take an analogy like that and then apply it accurately which is also important and that way when people walk away they can know oh I get it I get how this works I get the the NAT commands for the net options for inside local inside global outside local outside global I have heard that five different ways to Sunday or maybe six different ways to Sunday and many of them are wrong they're not there a wrong way of looking at it it's like well you read that of a book from something you wrote that then you're repeating it and you run so that's our topic tomorrow this is a it's been a pet peeve of mine for a long time with Nats network address translation and how it appears in the output most people gloss over it or they talk about it incorrectly many times and from a as a CCIE for routes which first and then for security I had to dive into NAT with a SAS and firewalls to really understand it not just from a security perspective but does make it really work and that was the long time ago now since then I have revisited that topic and I've had opportunities at major companies when we had we got bought out like when Paramount Pictures was bought out by Viacom we're talking about a huge company being bought out by a much larger company back in like 94 95 we had overlapping IP addresses I mean we had tens that matched their tens and to make that all work until we could read ress we had to do bi-directional NAT which is lying to each other about the addresses and so I've had a long story short the opportunity to practice and work with that in the production environment and tomorrow I'm just gonna lay it on the line as far as okay here's a great way to look at this here's how it works give you a couple concrete examples and if you join me for the IT elf discussion where IT elf can help remind us the process to going into full adjacencies of those PF the in it the to way the X start exchange and loading and going into full IT elf IT elf ITL is hard to forget that and what I'd like to do is give you a way that when you see a show IP net translations in the future and a command-line interface or from an output maybe you had a automation device gather all that data print them off on five different routers we're getting there translation tables when it says inside global or outside local I want to give you a very quick way that you could say oh I totally get what that is and I totally get the perspective and that's going to make it much easier to troubleshoot and implement the commands in the future so thank you very much everybody for joining me I'll see you tomorrow same bat-time same bat-channel 11:00 a.m. Pacific for CCNA Sunday as we discuss the world of network address translation and the terminology from the show IP net translations and with that I leave you with the song and I wish in my heart for you my friend to succeed big time bye everybody [Music] [Music] [Music] [Music] [Music] [Music]

Channel: Keith Barker

Views: 12,985

Rating: 4.9902201 out of 5

Keywords: 200-301, 200-301 ccna, 200-301 cisco, 200-301 videos, 200-301 exam, 200-301 ccna certification, 200-301 study, cisco, ccna, networking, cisco ccna 200-301, cisco ccna certification, cisco ccna training, subnet, subnetting, subnetting made easy, subnetting tutorial for beginners, subnetting in computer networks, ip address, host bits and network bits, subnetting host bits, reverse engineer ipv4, subnet range finder, subnet range explained

Id: wP3NRjxkCas

Length: 135min 1sec (8101 seconds)

Published: Sat Mar 07 2020