This ones a bity tough for me because I am also troubleshooting an issue with my file server caused by a blackout in my area where I live.
Brenden and I set about to gain access to the two switches that allow us to create VLANs. But we couldn't access them. We couldn't identify them over the network. It took hours to do but we did many searches on Nmap, quick searches, thorough searches, ping searches, a bunch of things. We didn't get any returns that would tell us what the switches were. We were thinking we would just access them wirelessly over the HiddenNetwork. So we kept trying to access them through the router over WiFi. We were flummoxed.
Doug then told us what we were doing wrong in Nmap was that when you type in the target, we obviously wanted a range of all devices connected on this network so that we could try and find these switches, so Doug explained to me that we needed an IP range, which is where CIDR notation comes in.
I typed exactly as Doug said to type, putting in the Network address, which if I remember correctly for the HiddenNetwork was 192.168.117.0. And at the end of it you enter the CIDR notation, which in this case I believe was a "/24", meaning two hundred and fifty six (256) usable addresses minus two (-2) because the last two addresses cannot be handed out. One is a broadcast address for all devices to contact the router when they don't have an IP address yet or if the router needs to announce something to all clients but they may not all need to respond.
So I typed in /24 and then we got a range. Oh, now I am finally getting something. We found two devices by the same brand as the switches and we logged into them using the admin Mtech123 password, and a live image of the classroom came up on one and then the other, and we discovered that there were two IP cameras that were also from the same brand, I think it was TP Link or something like that, and so these were not the switches.
We combed through the ist multiple times, both Brenden and I and couldn't figure out what the deal was. Brenden decided we must have been doing the Nmap search wrong because he didn't understand CIDR notation yet, I understood what it was used for but I still need to get the hang of converting binary and decimal and getting the network address, default gateway, broadcast address--I think, the subnet mask, and how many devices this supports.
So I tried to explain it to him and this is where Doug happily shot right into a lecture on the board about how to do CIDR notation so Brenden started doing conversions on the board and handed the marker to me and I said, yeah, I know, I just need to get better but this isn't really the time, we need to finish the project.
I think he and Jack, of course because Jack loved converting back and forth between binary and decimal and likes to get crazy with hexadecimal and so on, just for fun. Funny guy! He'll now also be a stud to the geeky girls. He's already making me look bad by passing one of the last certifications by five more points than me haha!
Brenden was like, yeah we should do the project. So we were back in our dead end because the Nmap search didn't actually return the switches apparently. We started to wonder if everything was being listed in this search and if possibly there was a different search we should have been doing.
Doug came back around again and he was like, yeah, you know why you're not finding it, and I interrupted hi with, wait, you knew something and you didn't tell us? And he was like yeah, I'm supposed to help you learn, not just give you the answers. Ah, yeah well, I will learn it, after you tell me the answer! No no no no, you need to discover it yourself.
Yeah, another funny guy here. He's already married so...no jokes about finding a geek. Apparently he already um...well she's in IT. Tss! No Doug, don't read this, hack my server and delete everything; I didn't call her a geek...
Okay, so he knew why we couldn't find the switches. I was on the edge of my seat. And he said that switches aren't going to show up in any searches. I'm like, wait, we can do a traceroute ping. I was already almost opening the CMD when he said no, that won't work either. What? Why not? And he was like bro, because it's a switch. Yeah, it's a switch, and there are routers, and servers, and so on. Wait...does this have anything to do with it being a layer 2 or 3 or whatever device? Yes, it's a layer 2 device. That's why. Huh? How does that mean that it won't show up. It has an IP address of its own doesn't it?
Okay, so they are layer two devices, but they just pass things on in a smart way using Mac Addresses and do not respond personally to things like pings and other stuff like that. They don't respond to higher layer protocols such as ICMP and other stuff like that, which is used by Ping and Traceroute. They do occasionally have layer 3 capabilities such as routing traffic between subnets or VLANs, but they mainly operate transparently.
Alright, so we thought that now we need to just connect a machine directly to them. My laptop was the ideal machine to connect because it was small and light and easy to tote around. But since there were problems with it already, as Doug must have mentioned because I don't remember where this came form, maybe this came from our trying to search for the switches and not finding them and something we did should have worked and didn't and so Doug said something like oh yeah that's probably because the last students that set them up did it wrong. So Brenden looked up how to reset them and did both of them.
This was important. When connecting my laptop to the switch directly to enter the switches automatic IP address that it has when reset and not connected to a DHCP server, it had something like 192.168.3.0 or something, I can't remember exactly, but in order to communicate with it and do passwords and usernames and VLANs and everything, I had to go into my network settings, which for my windows 11 laptop was to press the windows key and type network settings and clicking on "Manage Network Adapter Settings" > select the active ethernet adapter > expand it so the View Additional Properties > this exposed the edit button we then pressed > the ore familiar Ethernet Properties window I am used to from windows 10 then appeared > scrolled down in this window till I saw "Internet Protocol Version 4 (TCP/IPv4) > highlighted it > pressed properties button below the scroll list > Your computer is provably already set to Obtain an IP address automatically, but for this particular operation you need to switch the top bullet to a static address by selecting Use the Following IP Address. You have to enter the same address as what's on the bottom of the switch as its default factory reset address. Then when you type it in the browser to access the switch as well, for some reason it works. Then be sure to switch it back when done.
I did some research to understand why this works. Apparently you need the ability to set up switches even if the DHCP server is unavailable. Coming with a default IP address allows this. However, my research indicated that you don't need to create a static IP address that's the same as the switch has in order for this wired (direct connection) to work, it just needs to be in the same subnet as the default factory reset address the switch comes with. This makes sense to me, it really didn't make sense to me that it had to be the same exact address. But I recall that we put in the exact same static address as the switch. So...yeah. It just seems to me that this shouldn't work if they have the same exact address, including that fourth octet to the lett...number.
We grabbed an ethernet cord in the last like ten minutes of class and spent a bunch of time trying to log in, set up usernames and passwords on both, I had trouble wrapping my head around what the bridge cable was for so they had to stop and explain that to me like thirteen times throughout the class because either Doug or Brenden would keep plugging it into one port or another or unplugging it completely and then we needed to make sure to do that reset without the two switches being plugged into each other or else it'd wipe both of them out at the same time or something. I just couldn't figure out why we would have a bridge cord and what it did.
This turned out to be quite an embarrassing revelation to me when Doug broke out the marker again and went to the whiteboard JUST FOR ME. lol. I should have deduces this and I just couldn't figure out why a bridge cord was necessary. It was a forrest for the trees thing apparently because I knew what VLANs were for. Say you have personnel all over the building, spread out from each other or something, and they are all on switches that are shared with other departments, you don't want accounting and human resources to be on the same network so human resources is all up in paychecks and budgets while accounting is digging through write ups and reviews. They may be on the same network but they need to be separate from each other, virtually compartmentalized. How do you do this? VLANs! So what happens when you have a bunch of accountants on the same network but different switches? How can they be on the same VLAN if those two switches aren't directly connected to each other through a bridge port on both switches so those clients can communicate directly with each other?
Oof. I knew this. In fact I think Doug explained it to me like four months ago or something.
So yeah, we connected, created usernames and passwords and created VLANs and designated bridge ports one switch at a time. Then we were done! So most of three hours later, it really did take just a few minutes, fumbling around in the switches web interface included.
So we came to class the next Monday and there were several problems. HiddenNetwork wasn't working. So I didn't have internet so I switched to the student network I don't like much because it seems sort of unreliable.
Doug started looking at the problem and it took all class to troubleshoot. First, Doug went to the L3 features (level 3 on the OSI layers) since this is one of those layer 3 switches, then on the side panel, he clocked on Interfaces > then switched from static IP address configuration to DHCP > and hit apply.
This was far from over, that was just like a fifteen minutes of troubleshooting to solve or something. The switches have indicator lights on the ethernet ports, and there are two lights that are supposed to be green, either blinking really fast or solid green. If they are orange or any other color, or off, or some other blink, then that indicates a problem, and each of these things means something specific. Doug noticed on the switches that one of them was only operating at Fast Ethernet speed of 100 megabits per second instead of the gigabit ethernet they were capable of because one of the indicator lights on one of the switches was off altogether. This cord was plugged into Ronald's computer, and that end didn't have indicator lights, so when looking at the switch, Doug noticed the problem on one end, and tested the cord to discover one pin was damaged. He changed the cord.
In settings, there were two tabs, one said VLAN settings, and the other said PORT settings. Brenden and I configured the VLAN but we didn't configure the ports to be apart of the VLAN. So in this switch there was a button right next to VLAN config called Port config and you set each of the ports in this page by selecting them and under PVID, while the ports are selected, you type "2" into the box and press apply. This is only for the ports that were supposed to be on VLAN 2.
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