Lecture Troubleshooting Network Connections

alright guys welcome to Thursday's class last class of the week of memory serves me correctly we only have two more weeks after this correct your group project will be due I think it's May 3rd it would be the last Friday not next Friday but the Friday after that ok it will be due online and then I'll have them graded for you and give them back to you when we see each other on Tuesday for the final remember your finals in this classroom at 8 o'clock in the morning consists of two parts a 70 multiple-choice question and a 30 point hands-on that requires the use of Word Excel and access I say this just to remind you because starting next week we'll be doing nothing but integration what I have scheduled for today's we're going to be going over the troubleshooting a network talk about the different types of mediums that allow our devices connect together and then go into PowerPoint to show you how to add your voice over to your PowerPoint presentation all right the program I'm going to show you guys today will not be installed on your home computer it's used by Cisco network administrators to teach them networking theory because it's a tool to use to teach networking theory I thought I'd be perfect to show you guys basically how to build a network without going out and buying the hardware and doing running the cabling so somewhere on your desktop there should be an application called Cisco packet tracer you guys have that remember you don't need to know how to use this you don't need to have this installed on your home computer I'm just doing it today to try to create a learning environment for us when it comes to networking because remember the definition of networking devices are it's our definition of a network is when you have two more devices connected together to share resources so when you guys find that icon just double click on it if you get the little preference message just click OK and then you should be out here this drawing board is that what everybody has all right so to create a network this virtual network we need to have two or more devices more importantly we to have end devices so down here at the lower left corner of the screen is a picture of a PC go ahead and click on that then over here in the center area of the tool palette click on the very first generic icon it's just a desktop PC after you click on that once come up to the canvas the whiteboard click once and you should be dropping a PC on there pc 0 is that what you guys have remember this is like a virtual network that we're about to create do the same thing come back down here click on that generic and add another one because we need two or more end devices so you guys should have pc 0 on pc 1 we need to connect them together if there's only two computers you might be able to connect them together via crossover cable that's beyond the scope of this class there's going to be another device that's going to be used to connect us to the internet so how the a crossover cable to connect both of these together would be rather frivolous because the only thing you could do is share files between just these two places these two end devices so what device should I be looking for acts as an intermediary device more like a splitter for my internet to connect these end devices to the rest of my network a router today you guys are used to calling it a router because it's usually integrated service router it has a switch a router maybe even a wireless router built-in so down here first row second icon in from the left is going to be a switch so if you click on that go ahead and click on this first 2950 icon you see that - 24 all that's telling us is that this has 24 ports so click on that once to come up in the canvas and click on that like I said the - 24 tells me I have 24 ports that means I can connect 24 devices physically this network what if I have more than 24 devices I could add another switch connect 2 switches together and then now I can connect up to about 47 46 because 2 of those ports are going to be lost to connecting this with just alright now we're going to need a router to connect to the internet so on the very first row very first icon that looks like a little cylinder click on that once and then click on the 1841 router very first icon and I'm just going to add that right here to the right of the switch now like I said when Adam said well a router the home products will usually have these devices grouped together then you guys might have a modem to modulate that's probably going to be changing as we start getting fiber more to the home and we won't be needing modems to modulate signals anymore the reason we have modems today is because we're taking what we're used to transmitting across the local network and trying to transmit them on an existing network like your telephone network like your cable TV all these are different forms of networks if you will so the modem basically modulates the signal from what we're used to on this network to the way in the wide area network okay so we have these components thrown into my home if you will now you need to connect them together so we're following the ethernet standard that means I'm going to be using a cat5e Ethernet cable you see this little lightning bolt go ahead and click on that lightning bolt now this tool does not exist in real world but we're going to do that I want you to hold the control key and I want you to click on the first lightning bolt icon over here in this group what that'll do is a lock that tool this is an auto connect tool like I said it doesn't exist in the real world it makes it easier for me because I can click on PC 0 go ahead and do that and then I can click on switch 0 auto connect now when I'm teaching this stuff especially my networking students I tell them that's a tool that you'll not allow to be used in package rates or because it doesn't exist in the real world let me show you why cuz you guys hit the Escape key on your keyboard come down here and click on that solid black line to the third icon in now click on PC 1 you notice when you click on PC 1 you're greeted with a choice I prefer this although this is emulated and it's not like this in the real world when you look behind your computer you're going to be looking at all these different ports do yourself a favor when you go to connect your ethernet cable to your switch there's only going to be one port that this cable plugs into one type of report don't force it and I worked for an Internet service provider we were switching our clients from dial-up to DSL and they were trying to save themselves a lot of money because at that time a lot of the computers did not have network interface cards they thought well this cable looks no different than a telephone cable so I'll just put it right in our dial-up modem now when you go to look at a dial-up telephone cable and compare it to an Ethernet cable this connector this Terminator is a lot bigger it has 8 pins your dial-up phone jack cable has 4 pins till to this day I'm amazed that they were able to jam something like this into their dial-up modem folks if it doesn't go easy don't force it this is the sound it should make if it goes well just nice little click notice I didn't have to get out the hammer to slam this thing in so when you guys go to connect your laptop or your device to your PC you want to make sure you look for a port that looks like a glorified telephone jack if you will it has a tongue on it the reason why that tongue is in there is so we position the pins correctly and it holds it in there now when you click on the switch you see you're greeted with basically 24 options it truly does not matter which port on your switch you use to connect your end device to I'm going to click on the Fast Ethernet 0 / 2 bless you the last thing I need to do is connect the switch to the router and I got to be very careful about this so I'm going to come over here click on that solid Blackwell icon again click on switch 0 I'm going to choose port 24 I chose port 1 for PC 0 in port 2 for PC 1 but now I'm choosing port 24 for my router the only reason why I do that is my router acts like a gateway a way out so if I use the last port on my switch I can quickly associate that the last port is with my router and then it helps narrow down now the reason why I bring this to your attention is your homes are going to get smarter the people that build your homes are going to get smarter we depend on the network they're going to be a little bit more self-conscious about where they put things for example your circuit panel that controls all the different outlets in your house is conveniently located in one room today we're doing this ad hoc network we go out to a Walmart buy this integrated service router or wireless router throw it anywhere in the house we got cables run all over the place what is the advantage of taking all your networking all your telecommunications all your entertainment and putting it into a rack like this and putting it in a closet somewhere in your house or underneath the stairs let's say it's centrally located ok so by having essentially located everybody plugged into this once area you could probably put a server in there that connects to that to do all your backing up good it's convenient because you don't have to run all over the house wondering what Computers causing the problem you go to this switch you see these lights and now you're like okay which one is this which ones that is like you're you know slicker breaker panel hopefully they're labeled if they're not labeled what are you doing flipping each one of them turn any things off that doesn't need to be turned off likewise here but the important thing is it's going to make it easier for you to upgrade you're not running all over the place checking all the different things out there now I make a point this because eventually everything in our house is going to be controlled by computers this includes your outlets right now I have no way identifying this outlet from that outlet we call this unmanaged now if you guys go to Best Buy you'll start seeing that they're selling these little adapters that you can plug onto these outlets they can control with your smart phone so it means when you're on vacation you can actually turn your lights on and off and why would you want to do something like that yeah to make it look like you're still home so giving you a heads up this thing is going to merge into you and you guys going to be using it quite a bit so when I click on this router by the way what I'm trying to say is these home products you buy they're getting more intelligent hence they're gonna get a little more complicated yes yes exactly everything that's what I'm saying it's getting to that point yep so when I click on this router you see I have multiple choices now I'm just going to choose the fast ethernet remember the router or the Gateway is basically connecting two networks together this classroom is connected by that hallway to the other classrooms that's a different network than in here remember I told you this the local area network you'll see I have a bunch of red dots if all goes well in the real world and you go to take a cable like this and hook it up from your switch to your end device your end device and your switch will have lights on it they'll either go green or orange depending on the speed if you're not work if they don't light up there's either something wrong with the cable or the interface is turned off so first thing when it comes to troubleshooting check to see if the lights are lit up if your lights aren't lit up check the cable now the way I do it or the way I might do it is I might take one that is working and plug it to the port that might not be working this way I know the cable is functioning if the light doesn't come on then there's something wrong with the port and I might have to buy a new switch if the light does come on and there's something wrong with the cable and I have to make a new cable or buy a new cable here I know I'm not gonna be able to communicate with the router just yet because the lights are off so like I said step one for troubleshooting check interface / port lights should pc 0 and pc 1 be able to communicate with each other well the first roll is done right first step I have green lights let's test that let's click on PC 0 now the way you would do it in the real world is you would hold your window key you hit the letter R and you type in CMD and you get that black command prompt here we're just going to click on desktop then want to click on command prompt pretty close to what we're used to seeing remember last week when we did this was a black screen with some white text now the tool that we use when it comes to check connectivity is called ping I'm not going to put that up into the steps but I'll just write the command up here for you so you have it paying space followed by the computer's IP address interesting I want to talk to PC one in order for me to send a message to PC one I have to know what PC one's IP address is so let me close out of PC zero then they click on PC one let me click on desktop let me click on the command prompt now I'm going to use another command called IP config all one word so here at this prompt I'm just going to type in IP conf IG and I'm gonna hit enter you guys have a bunch of zeros in there depending on your computer there might be a bunch of zeros it might be some number and 120 so are 167 range this is not good this is telling me that I haven't configured my PC yet now most of the time our PCs are automatically configured for us using something called DHCP let me boot up your computer a device on your network will automatically assign an IP address this is where it gets really tricky you guys might have multiple devices whether it's a wireless router or the box from Time Warner who has that service running and both of those services are designed to give up a certain IP address so half your devices on your network is getting one particular IP address and the other devices are getting another they're not going to be able to communicate with each other so the second step for troubleshooting check the IP address of each device per device the way you do that is type in IP config this is of course implying that you use a full-blown computer if you're using a tablet or a smartphone you might have to go to the Preferences of the settings and click on the interface and then they should show you the IP address stuff all right so hmm this computer doesn't have an IP address let's close add just the command prompt so click on this little X right here somewhere on your computer there's got to be a way to configure it whether it's manually automatic in this particular computer it's on this button sorry this simulation so click on IP config you have two choices your DHCP and static that's basically what Windows is going to do for you so they're going to be automatic or manual in this exercise we can do it as a static let's click on the first IP address block sorry text box what number should I put in there guys it might be dependent on what your time-warner router is or maybe what your wireless router is so don't get willy-nilly and say I'm just going to make it this if you have a device that's already sending out IP addresses are already pre-configured you might want to find out what their IP addresses and try to match it since we are creating this network we're going to go and change all those devices to match our addressing scheme alright so let's start off with a number what's my range what number can I pick between 1 and 1 0 2 up to 55 I'm going to type in 192 what am I going to put after the 192 dot yep now I'm in another octet what's my range from what to what zero to 255 all right I'm going to put in 168 now why am i picking this number this seems to be the de-facto Class C private addresses that you guys will experience by go out and buying a home device like a wireless router switch or whatever the case may be all right so let's put in a 1 dot let's make this one yeah one will do just fine hit the tab key did it automatically complete with 255 dot 255 dot 255 dot 0 good they're telling me that the first three octets have to be the same on all the other devices on my network is that clear I said any number that has a 255 underneath it is telling you that it should have that as network address the network address for this device is one ninety two dot one sixty eight dot one dot zero well good with that the other thing we got to follow is no two devices can have the same IP address so the next PC will plot B dot two what about the Gateway address the Gateway has to be on the same network as my PC correct hence the first three is already told by what I have established I cannot change it to anything else without changing these the last one is interesting I can't use dot one why not because that's the PC I'm on right hmm could dot to work possibly if no other device has it I always like to think of my Gateway as the last device before anything leaves or comes into my house right so I'm going to give it the last IP address of 254 because remember the range goes from 0 to 250 for there sorry 255 0 is commonly used for a network address and 255 is commonly used for a broadcast address so I have this usable range between 1 and 254 so I'm going to make that my gateway hmm I also have this DNS server can anybody tell me what that's about it's important when it comes to troubleshooting why are they asking for that do I need to fill it in typically on your home computer you can put in your gateway address as your DNS address Chameli folks what is DNS domain name service this is the service that allows us to type in google.com and it'll convert that domain into an IP address because anything that's traveling on the network must use IP addresses if this is left empty that might be an issue so let's close out of that let's go back to that command prompt and type in ipconfig again do you see when I type in that command I go from nothing to actually something ok let's close out of the command prompt let's close out of this dialog box let's go back to PC 0 let's go back to the command prompt now let's type in ping space followed by the IP address of the other device so after you get the IP addresses next thing is to ping a neighbor so paying a local device and the way you do is type in ping followed by the IP address of that device so what was the address for that device I'll do the hard part one ninety two dot one sixty eight dot one dot what are you going to put after that last dot what was the IP address of the other device dot one did it fail yep so that's their equivalent of failing it means it gave up because it said hey not one are you out there dot one are you out there and it's going to try about four or five times and if it's not getting a replied it's just giving up so we don't have any communication between PC zero and PC one but PC one has this IP address of one ninety two dot one sixty eight dot one dot one what's wrong let's type in ipconfig and as we can see I have nothing but zeros now you guys hit the pause button for a second and let me show you what actually goes on edit filters show none and we're going to do this and you come back here so logically what I want to do is I want this PC to talk to this PC so I have this envelope and when I do it I'm getting a little red X and the reason why I'm getting that is the protocol states if you're going to send a message to whoever you need a source IP address and a destination IP I dress this is like you guys trying to mail something in your mailbox and you don't put any addressing information on the envelope the person who picks up the mail is going to look at this and say well that was a fun joke and throw it back in your mailbox it's not going to leave your mailbox unless you have both the source and the destination let's go back into real time we need to give TC 0 an IP address so close out of the command prompt click on IP config what's the first 3 octets going to be for the IP address 192 dot 168 dot one what's the last one going to be two seems logical why were the first three one ninety two dot one sixty eight dot one because we have to follow the pattern that we set up on the other PC let's click on the subnet mask by hitting the tab key does it autocomplete what are you going to put in for the gateway 254 there's only one door in this classroom if to get out there okay I know there's another one but there's only one to get out there on the hallway and this will happen on your home computers too because you guys might be buying multiple wireless routers because your one wireless router can't reach the second floor and so the wireless routers could act like a gateway the problem is they're sort of like internal gateways it's like having multiple doors inside your house so there's only one door to get out here to this hallway all my devices just like you guys must use that to leave here correct so our mouths will give that the right information so number four verify that it's properly configured so verify configuration make sure when you're verifying your configurations you do it for all pcs and that certain things have a consistent pattern same subnet mask same default gateway and guess what same DNS probably should be using the same phonebook let's close out of that now let's go back to the command prompt hit the up arrow twice did it autocomplete the ping one ninety two dot one sixty eight dot one dot one if it doesn't just type out ping space one ninety two dot one sixty eight dot one dot one hit enter and did you get replies replies our good thing that means pc 0 and pc one are able to talk to each other alright hit the pause button for a second and let me show you what this looks like logically it leaves my pc it goes to the switch the switch reads that information rebuilds it sends it out the appropriate port that PC gets it needs to respond back to PC zero letting it know that it received it so it generates a message sends it back to the switch you see how the switch is like Grand Central Station and the back to PC zero pc 0 is happy because it gets a reply so it shows you a little green check mark you don't see this in real world that's why I use the ping command if you get requests timed out a request unreachable then you have an issue whether it's IP information not being set up correctly cable failure or something wrong with the interface card so great let me go back to real-time what if there is something wrong with the interface card see here I had you guys ping the local device using the IP address but maybe the first thing I should had you test is to see if the stack is okay sometimes we get viruses if a virus can imbed itself in the stack it can all act almost like the switch and that is any information that's leaving or coming into your computer it'll read first folks when you enter username and password that's information it starts up here at the software level and it's got to work its way down to the stack if that information is right up here before it gets encrypted which happens down here I'm going to embed my virus right in the middle if a virus has to read the information it's going to take time for that message to get from the source the destination sometimes things give up because they are time sensitive because they have a security issue so when you ping things another thing you should ping in here is called the loopback address which is going to be ping space 127.0.0.1 in fact that's probably should be the very first thing you ping before you ping anything else the loopback ping check to see if the stack is properly installed if it fails you have something internally wrong with your computer whether it's a virus or a poor driver being installed don't call your ISP up unless you want them to come out and fix your computer and charge your hundred dollars an hour ok that's why we call it the loopback or the local ping because what it's doing is testing your software the next thing you want to ping after you do your loopback is your own IP address the self IP address the reason why you want to do that is because you need to check to see if your network card is functioning that is to say if it's firing out those electrons on the cable if it's not then you might have to buy a new network interface card okay there's two things to check if those two pass then pick a local device by pinging a local device did you see how you're able to test the cable then the switch then this cable if that failed it might be that you don't have the right IP address what else could be the conditions if you tried pinging this device and it failed what do you guys think so if you tried pinging here to there and it fails you already ruled out the IP address what else might be could be the connections what else could it be it could be this intermediary device right if that happens I suggest you unplug the switch let it sit idle for a little bit and then power back on if you guys experienced this with your wireless routers it's also gets slow and it's dropping these packets well your wireless router is getting a bunch of electricity through all these different packets and it's going to overheat we never think about this we never give it a break we never turn it off before we go to bed we always want it to be running all the time and I mean it's listening to the airwaves whether somebody's sending a packet or not there's always something going on in the air that we can't see that those antennas can detect and it's constantly processing it so these routers get over worked hence they get really hot and sometimes they need to cool off so if you power them down give it a couple of minutes maybe a few hours depending on hot of this let it cool off turn it back on see how well it works if it's back to working the way it was then that's all it was was overheated now this heat can cause damage these wireless routers only go from 50 bucks maybe a hundred bucks they're designed to be throw aways they could probably get you through one year of aggressive Internet traffic throw them out you buy a new one if you're tired of replacing your wireless routers and you have to buy a high-end professional-grade one which has a cooling fan built into it to keep it running okay so try that this is what happens switches wireless routers the whole nine yards they don't cool off properly they're overworked turn it off give it time to cool off turn it back on see if your ping works it might work for about five minutes and then go back doing it same thing if that happens what do you guys think you should do turn it off for five minutes let it cool down turn it back on it works for another five minutes and then it goes back to acting like it was throw it out and buy a new one because it's physically damaged okay what if that wasn't the problem no matter even if one out bought a new one and you plugged it in here and it's still doing the same thing focus on where the message is going right now all we've done is local test if this works and this fails check this if both of these fail in other words folks just don't try one local device try several of them if both of them fail then it might be the switch or it might just be you so go through this process ping this one great it works now let's ping the router what's the IP address for that router what's another name for a router the Gateway 2:54 so let's open up any one of the PCs go to the command prompt and ping one ninety two dot one sixty eight dot one dot two fifty four and hit enter it will fail but this time why would it fail the first time when we did something like this it failed because the PC wasn't properly configured correct if you type in ipconfig you will see that this PC is properly configured so why is it failing now our router isn't configured it's got to be both devices right folks let's close out of the PC zero let's open up router zero folks I'll guarantee you your router does not look like this in fact your wireless router the way you go to configure it your PI B via a web browser this is where the challenge comes in and this redtail students to do all the time when you buy your wireless router find a computer unplug your computer from the network in the box when you buy your wireless router is going to be cable like this from this plug it into your PC on this end plug it into one of the ports on your wireless router now turn on your computer that wireless router will automatically hand out the IP information for your end device the next thing you need to do when that happens is you go to your command prompt and type in ipconfig you will get that default gateway and that's going to be a number write that number down it might be one ninety two dot one sixty eight dot something when you have that number written down open up your favorite web browser type in that IP address in the address bar when you do that you're going to be greeted with a username and password in the little instruction manual that came with your wireless router we'll tell you what the default username and password is it's typically admin for the username and maybe admin for the password or simply password or left empty this scares the hell out of me because there are websites out there that have the most commonly used passwords for wireless routers if you do not change this then your neighbor can do the same thing I told you guys to do get into your wireless router and install things that could snoop on your network change your default password okay it'll be a self step-by-step once you get in there what we're learning now is very applicable to what you do there it will not look like this would be very user friendly it'll be a wizard to swauk you guys through it however we're going to do this because it's just simulation click on config tab click on the fastethernet 0/0 after all that was the interface that we use to connect the switch to the router you see it's turned off turn it on down below you see who says IP address click on that box type in one ninety two dot one sixty eight dot one dot what what should the IP address of this device be g5 for I am now giving a device on my network this IP address that's going to act like my gateway all right click on the subnet mask box did automatically put in the three 255 s followed by zero good closeout of the router zero you see how this lights blinking now then you finally went green they're negotiating with each other Green's good go back to PC zero go to the command prompt click on as I type in ping one ninety two dot one sixty eight dot one dot two fifty four and it should work what if you checked everything and you still can't ping the wires are right you went out and bought five brand new wireless routers and they're all failing or you have all new computers and they're failing but the loopback work the self IP address work but when you go to ping another local device on that network it fails let's think about this for a second in order for the ping command to work you are sending a message that message is knocking on that end device to see if they can come in if it replies back to you that means that message gets in there there's this threat called denial service attack and just a glorified ping command that bombards a server with these silly messages by bombarding the server with these silly messages the server's monopolized that means it can't take care of anybody else but the person who's pinging it hence the denial of service these are like somebody in your class raising their hand and they just go on and on talking and you can't ask your question so there's got to be a way to block pings if you try paying a device and it fails and you did all the other due diligence the next thing you need to check under verify your configuration check to see you have a firewall installed on my final exam that I give my networking students I make sure that firewalls turned on and it's designed to be a real pain in the ass when it comes to pings and I don't know how many of my students will go through all those things checking the loopback checking local addresses and so on and fail to realize that the firewall is blocking it in fact last Thursday you guys remember we had a problem logging in and getting out on the Internet they installed something new on the network and guess what that something was as a firewall they installed it on our server and it was designed to block everything everything authentications as you guys can sign in or took forever internet connections follow sharing these are things that you want to do for your server these are things you might want to do on the end devices so we fixed it we turned off the firewall it's a good idea to turn off firewalls no inside those firewall services or applications there's a way to add rules that allow certain traffic to come in and go out you guys ever worked with your firewall maybe try to use this application it said your firewalls blocking it or maybe it might pop up saying you give this application permission and if so how long these are you making exceptions to the rule okay so that works let's see if we can ping Google though ping space www calm what makes this ping different than the other pings yeah it's not in my local area network so now I got a whole nother set of things to check out for first of all I pinged not an IP address but a domain correct the first thing that should have done is taken that domain name and convert it into an IP address you guys can see this hold your window key hit the letter R type in CMD and click OK you have that real dos command prompt now type in ping space www comm and then hit enter you notice you're getting replies from an IP address now this is one of Google's IP address looking at the other fake das command prompt I don't get any replies from the host do you notice I'm not even getting requests timed out I'm getting absolutely nothing but in the real world I am that's because something's working in the real world that's not working here and we're going to take a guess what are this think about this we're no longer pinging the IP address that's we use for straight - straight conversation the difference between this two is like when you hold your Siri button and you say call Bob in order for call Bob to work there must be somebody named Bob in your contacts is that right the opposite is call then the number right six zero seven nine six two nine five six four the difference is one's more of a direct approach here when I ping an IP address I'm dealing directly with the host when I ping a domain name I'm not dealing directly what must work in order for the domain to be resolved to an IPS the IP address you got a check and see if your DNS works one thing is if it's properly configured if your local device is configured to have a DNS address if your end devices do not have DNS sorry a DNS server address then it won't be able to resolve it number two the service is running most of the time your DNS is routed to your ISPs DNS the way you can track that is using a command called nslookup at Shore for name server lookup when you're at your das command prompt and you type in nslookup space put in the domain name google.com and hit enter it should give you all the IP addresses associated with that domain if it's not running this will not come up it will fail what can you do about that first thing is properly configure it so it's the IP address of maybe your local gateway or you use something called open DNS which is a Google DNS and put that in there if that doesn't work you need to check your internet connection how do you check your internet connection how did we check our local connections we paying a device right hmm can you guys give me a device that's on the internet that I could pink any one of these IP addresses it might be just so you had these for your own personal notes because if your internet connections down you're not gonna be able to get this or if your dns connections down you're not gonna be able to get this so you might want to write this somewhere maybe on the bottom side of your wireless router to have some publicly available IP address that you can ping because folks when it's down this is the only thing you could use to test that or you call a friend up be like look can you ping Google and tell me what the IP address is so that I can ping them so let me try that let me ping 173 dot 190 4.46 dot 32 and hit enter and I got replies so step 6 this is the check your internet connection ping a public IP address if you get replies this way but you get failures when you ping the domain name that's that should tell you that you have a problem with your DNS correct if you get replies with this it should tell you that your internet connection is working because the only way you can get that reply is when it leaves your wireless or when it leaves your router travels through your cable connection or your fiber or your airwaves whatever the way it is you're connected your house to the Internet arrives at the destination it comes back so if they work do not call your ISP and say my internet connections down they'll call them and say I'm having a problem with my DNS but repeat these steps go to another local device and do the same thing ping Google if all your devices on your network cannot ping google.com but they can all ping the IP address that represents that then call your ISP up and say I'm having a problem with the DNS server okay what if this fails both of these failed pinging google.com and then pinging their public IP address you can ping your gateway that works so let me close out of some of these things everything up to this point works anything beyond this point fails there anything you can do in your power before you call your ISP because folks what they're doing now is it's your fault if there's something wrong with your equipment you're going to get billed for that time so you need to make sure that when you call them you feel 100% confident that it's on their end otherwise when you go look at your bill it's going to be like an extra hundred dollars just for that telephone conversation what's the last thing you can do before you call them to verify that everything is kosher on your end your ISP is going to give you some type of device we call that the modem on that device is going to be some more lights there's probably going to be like a status or a link light letting you know that your modem is connected to their office if that link light is not on and everything else up to your point is good check your surge protector in my an electrical storm and blow out the surge protector that means the connection between your their office and your modem is broken because the surge is blown the surge protectors blown okay plug it directly and see if the link light comes in if it does come on simple go buy a new surge protector if it doesn't come on then you call them because from the point from your house to their office there's something wrong if the link light is on turn off that device give it a couple minutes to cool off turn it back on if it's working and then it goes back off in ten minutes you might have to call them up and tell them looking you to replace your router it's or modem it's overworked making sense folks you see these six steps to follow through just to cover your own end alright last thing I want to teach you is called a traceroute command all this could be on but you're trying to get to a particular site and it's failing now you can know where the blame is at last semester or maybe it was a year ago we had that flood I guess was a year last September that right when that storm came up the East Coast it knocked out my IT lab and that their servers were down in like South Carolina or North Carolina and everybody's internet connection was working but when they went to go on the my IT lab it wasn't coming up and so I told my students what to do is what you guys are going to do right now is run this trace RT command number seven do a trace route all one word followed by the address so I'm going to type in trace Archie Space 173 dot 190 4.46 dot 32 and I'm gonna hit enter I love this these are the number of hops remember our router is connected to another router which is connected to another router which is connected another router this is tracing all the different routers that my packets going through so I go to one ninety two dot one sixty eight dot one dot one that's my gateway that's the first router from there I go to a 10.1 12.1 28.1 I all know what that is it looks like that's a Corning server then it's going to go to a northeast roadrunner is that where everybody else got to so this is where my time warner connection is from time warner is going to Time Warner Cable comm East this must be Binghamton bgm from Binghamton it's going through their backbone which I have no clue where it might be at it might be in Albany I have no clue I could take these IP addresses and google them with google map and they can tell me exactly where they're at but it took me 11 temps to get to that server it didn't take you guys 11 might some might take 12 depends on different times you run it because you don't take the same path each time you get there but the cool thing is I get to see where it's going if it stops right here it doesn't go beyond that I'm going to get a bunch of little asterisks and then eventually a timeout after 30 tries that means I know that this server is having a problem and the important thing is is I know it's not me because I'm up to this point right here once it gets to here it's out of my house I know it's out of my house because I can just read the domain name it says RR Roadrunner nice little tool I'm not expecting guys to understand all the different components of it other than you can see where it's tracing where it's going to and if it fails it's not going to be able to do the rest of it you'll get success when it says complete this case it took 11 hops 11 routers folks I don't know about you but that should open up your eye to realize that everything you send out on the Internet it's being passed around to all these different devices what's to stop somebody one of these places to put a packet sniffing software on there and say hey I see so-and-so is looking at this I see so-and-so is doing that nothing at all your best thing to do is you encrypt your data before it leaves your computer so when they do get it it takes them forever to be able to crack the code and by then that information is obsolete hence change your passwords often but how often do we change their credit cards by the way you can take your computer and maybe a bunch of computers in your house and connect them together and you can crack some of these algorithms and maybe two or three years time and as computers become more and more powerful what do you think is going to happen to how fast it's going to take to crack them you can be able to crack the encryption a lot sooner correct so my question is how often do we get a new credit card number well usually your credit cards have a shelf life of every four years they're going to send you a new one or when you lose your card I think that's ridiculous I think you should be able to go on to your credit cards website and generate a virtual number that's good for that one transaction so when you make an order online like Amazon or Ebay you go to your credit card company you say generate a random number you copy that number and you paste it in that transaction and you tell the your credit card company what that amount is so right before you checkout Amazon I'll give you the grand total you go to their website you put that grand total in there and you generate that new number so that number is only good for that total and only for that transaction there's absolutely no reason why we should have numbers on our cards put a chip in there that chip generates a number automatically when you're in the store and you scan it through and it's only good for that transaction it's pretty barbaric that we treat our credit card numbers like we do our phone numbers now I know our phone numbers need to be static because if you're changing them all the time it's gonna be hard for people to reach you what do we do we tell our friends our new numbers this call me this is only going to be good or day well if everything is connected why can't we do that at our stores whether it's online or traditional before we check out it goes on to the computer and says ok this is the number way to give you for this particular transaction that's it like an order number if you well blend it in with thee I think somebody's going out and doing it I think I read something a couple days ago something I told my students 10 years ago they looked at me like like your mailing addresses this is we got on this debate about like Craigslist like the Craigslist killer I'm always waiting for one of those serial killers to come out just using Craigslist and I know there's been like here and there but when you guys buy something it's gotta be mailed to you right the post office is hurting for money why don't they create virtual addresses so when you order something offline you give them that number that box comes in and gets scanned it's a barcode and it says ok this needs to go to Pennsylvania once it arrives at the Pennsylvania Depot they scan it and it says ok this needs to go to Mansfield once it arrives at the Mansfield box they scan it it needs to go to the street you see the levels of security it adds this way I can feel comfortable buying anything online and that have to worry about people finding me because that transaction is only going to be good until it's delivered once it delivered deleted of the database food for thought alright so that's how we test our networks to make sure everything is up and running now you guys know where to place the blame if a blame youth replaced depending on where fails of different steps when you get to step 5 step 6 now you're talking to your ISPs

Channel: Nicholas Andre

Views: 58,949

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Id: MVvgRXZRbCI

Length: 60min 56sec (3656 seconds)

Published: Sun Apr 28 2013