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Source: https://www.cnblogs.com/index-html/p/4344082.html
Author: EtherDream
Not long after I went to college, I encountered a headache.
The second generation of rich people brought their laptops when they first arrived, which made us envious, jealous, and hateful, who can only play mobile phones. The terrible thing is coming, the power is cut off continuously at night, so the notebook can still be played after the lights are turned off.
Unfortunately, we also have a bedroom. After the lights are often turned off, the battery must be cleaned before giving up. Voice while playing the game, and music is still suffering. Although the persuasion has been improved, it will recover in a few days.
In order to urgently change this situation, but did not want to get in touch with the new acquaintances, he decided to use technical solutions.
But at the time, the owner had only one Nokia slider phone, and it was empty talk without equipment. The only feasible way is to secretly set a scheduled task in his computer and automatically shut down at night. But in case it is found that it is even worse, there is no technical content.
Reluctantly, he can only look away from the computer and on the Internet. If you ca n’t access the Internet, even if your computer can be used, you wo n’t stay up late to play stand-alone games.
Since his network cable jack was available when he first came, I must have a signal here. The last one must have passed, and it will never be sealed off after leaving. While there was no one in the dorm room, I dragged the laptop's network cable to my side and tried it. Sure enough, there was a signal! Suddenly came the spirit and felt hopeful!
Maybe you will say that it is impossible to connect the network cable to Nokia, and then use any spoof software ~ Of course it is impossible, how could the mobile phone at that time be so advanced.
In fact, we don't need any softness! Pieces! , Not even hard! Pieces! —— In addition to a network cable.
To talk about how to play the network cable, we can also talk about the day when the set-top box was installed a year ago.
For a time, digital TV became popular in many cities. This is no exception for us. The set-top box is presented door-to-door, and it is installed free of charge. Huashu TV and Netcom are the same company. Digital TV is of course sharing the broadband of Netcom.
Since Netcom has been opened before, this time I have to connect the set-top box to the Internet. I think at least I have to send a switch. However, as soon as the installer came in, he did not pull out the switch or even the hub, but cut the network cable with a pair of scissors!
I was stunned at the time, what the hell was this? Although I had some understanding of the network link protocol at that time and wrote some small programs for free Internet access with WinPCap, the physical layer was completely ignorant. The master said unhurriedly that only four network cables are enough, and some are spare. So from the previous line, four were removed for the set-top box.
This was unexpected, but I connected the set-top box without any equipment! So, it started to be whimsical again. . .
From the point of view of the exchange, are the two separate users two independent users? If you connect them together, will the effect be the same as inserting two wires in one wire? Can the same short-circuit LAN?
With a sense of excitement, sure enough! Really hang up the entire community network!
For a long time after the recovery, the number could not be dialed. In the sniffer, I found that many neighbors are constantly dialing. Obviously, the two 4-strand lines were just connected, and the external STP packets were also forwarded, resulting in the cell network being isolated from the outside.
On this day, the previous view was changed. It turns out that only one network cable is needed to get a VLAN storm!
Why does a network cable plug into the two ports of the switch cause a storm? Because the switch will forward the packet sent to the broadcast address to all interfaces. If there are two interface loops, once a broadcast packet appears, it will continue to send each other in a loop, exhausting the bandwidth of the entire device. Don't underestimate the switch, it is designed to send packets, the storm can fill up each interface, and hit the backplane bandwidth traffic. The STP protocol is to solve this problem and perform loop detection.
Despite understanding this new skill, the knowledge of the physical layer is basically useless, and it is forgotten-until the day when I came to the university and found a signal under the bedroom seat.
According to the memories, LAN games have been played between the bedrooms. Obviously this is not an independent network segment, so I am more confident!
Immediately found a network cable, cut off the crystal head on one side, scraped the outer skin, and then glued the corresponding four strands two by two. Sure enough, the nearby dormitory began to come-no, first it was silent for a few seconds, and then the screams and roars coming from the landing continued. "Stuck!" "Who has fallen?", What happened? "," Don't, the network is disconnected ~ "...
When I ran out of the corridor, the whole building was rioted! It turns out that there is no VLAN at all in this bedroom, and all the hundreds of bedrooms are connected together! ! !
At this time, both excited and worried. The excitement is that in the future, there will be a computer that can catch the traffic of thousands of people. The worry is that now I just want to spoof my bedroom, not want to involve everyone.
But no matter what, the action continues.
At this time, it was technically intact, and it was poorly implemented. How to operate calmly and concealed?
In order not to expose the absurdity of a computer without a network cable plugged in, I tried to route the cable along the covered cabinet from the back of the wardrobe to the bed. The remaining horizontal part is buried in the gap beside the bed and covered with a mat.
The whole layout can't be found if you look closely.
After turning off the lights that night, the night owls started to move around again, and I couldn't wait to start the experiment. Like several other classmates, pretending to be playing with a mobile phone has actually begun to quietly connect, quite the feeling of an underground intelligence officer.
When catching the last shot, the smooth game sound immediately appeared stuttering. After all, the entire building is in this LAN, and the number of broadcast packets is quite large.
I only heard background music left in the game, but no sound effects!
Thinking about 100Mbps of traffic passing through the network cable pinched in my hand, it seems to see the dense ARP, NetBIOS flashing in the dark-and the poor, squeezed out game data packets.
The commotion in the afternoon broke out again. Although it was much less after the lights were turned off, it was clearly clearer in the night environment.
Most of the disconnected are not reconciled and want to continue playing. This time, I don't plan to be so violent. In case the circuit detection is triggered, the whole building might be blocked.
So, change to catch a few seconds and disconnect. Then catch up and disconnect. . . Although the game can run, it keeps getting stuck. Soon afterwards, there were a series of warm shutdown sounds, and they went to sleep.
The first battle is won! Finally got a good night's sleep.
Pay attention to the WeChat public account "Python Space", reply to "The Way of Cultivation", and send an original high-definition e-book "The Way of Python Cultivation", you are full of gains, don't believe you want me to get a red envelope.
Improved v1
In the first few days, the effect was very good, and everyone obediently went to bed early.
But it didn't take long for them to discover that the network would recover after a while. The reason is simple. Brother let go of the line before he fell asleep, so they started to go crazy again.
In a sleepy dream, it will be much more difficult to put the network cable back on. Often irrelevant ones are also entangled together, and the results will be useless.
Therefore, an improvement in user experience is needed.
In fact, three of the strands were glued in advance, and actually controlled one strand. It's better to hide all three shares ahead of time, leaving only one beside you, so that you can't miss it.
Changed the network cable and made it again. This time, three of the strands were directly glued together and hidden behind the closet, leaving only one strand dragged up. The line is also much thinner.
In this way, it is the same as the circuit switch. There are two lines in total, just touch or separate.
Even in your sleep, you can easily disconnect from the network by simply moving your finger!
Improved v2
But with such a simple device, there will always be errors in operation.
In the middle of a weekend, after being awakened all night, he hooked up the network cable and continued to sleep. I didn't expect this time to be too sleepy and slept directly. It was not until 10 o'clock in the morning that he was awakened by a sudden knock on the door.
I thought it was a deliberate harassment by the student next door, but it kept going, so I had to get up and open the door. After opening, I found an uncle carrying a kit. At this time, I suddenly realized that the network cable I forgot to disconnect! ! ! After a whole night, they came to check!
It was too late to clean up at this time, and I thought this time I would finally be exposed. But the master glanced away and found that our table was clean and nothing. Only a notebook is open, and it has not been turned off. So he stepped forward and unplugged the network cable, then left.
Fortunately, he escaped this disaster and urgently needed improvement.
If it can be turned on before going to bed and automatically turned off after falling asleep, it is ideal. Never have to use your mind to disconnect in your sleep.
So I plan to make a flexible switch that must be pressed to open, and released to close. In this way, the body relaxes automatically after falling asleep.
After some improvement, the switch was made extremely concealed: two threads were tucked into a sock with cotton cloth and other elastic things stuffed inside. Normally, the line is separated, but it will catch when pressed gently, and then return to normal after being released.
But the socks were weird to pinch their hands, so they hid behind their feet. So far, whenever the night is noisy, as long as the toes tip toe a little, the surrounding atmosphere immediately becomes particularly quiet.
At this point, it took a total of two dollars to build equipment that allows toes to control the network status of thousands of people, which is simply too fulfilling :)
It didn't take long for everyone to discover the pattern, as long as the sound was too loud, the network would get stuck, but helpless could not find the reason. So they became obediently quiet online.
Of course, this device has only been in use for half a year. Everyone installed a computer in the second semester, so they went online happily all night.
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