He looked around and saw the students in the class practicing typing letters with great enthusiasm. It was not difficult to type. He practiced for a few days. Seeing that no one paid attention to this, Nick returned to the world of computers. He heard that government organizations, scientific research organizations and education organizations have a network of nationwide distribution. This is the government's internal network. I don't know if it is true. Judging from the current situation, these machines are not connected to the large network of nationwide distribution. Nick began to think that if there is a WAN, then the only one that can restrict these machines from logging into the WAN is the host of this microcomputer room.

Nick felt a lot of regrets. He had fantasized about the Internet world for so long, but in the end he could only contact the LAN like this. He was really unwilling to accept it, and he was really unwilling to accept it. The feeling of holding his breath in his heart was almost crazy.

What to do? Nick was sweating all his brain and thought, and suddenly remembered that a book about the Internet mentioned that computers can be controlled remotely and explained the general principle. He also said that computers can be controlled remotely through some means. For some reasons, this paragraph was vaguely skipped in the book.

Nick is naturally so familiar with the DOS system in front of him that he can't be familiar with it. Even if he has to rewrite it, he can do it. After thinking about its cabinet shelves and structure in detail, he found that the DOS system does apply for remote access.

I remember the book said that remote access is basically achieved through a password. You can access it if you know that the password is correct. The most advanced one is the super user password, which can control the computer with this password.

With his understanding of computers, Nick immediately thought of how to get a password. If it is a three-digit numerical password, there are only a thousand combinations, and counting from 1 to a number within 999 contains any arrangement of three numbers. If you don’t believe it, choose a few sets of numbers to try, such as 685, 865, 658, 785, 200, 139, 256. Any sorting is within 1 to 999. Therefore, there are ten thousand arrangements for four-digit numerical passwords, ten thousand arrangements for five digits, one million arrangements for six digits, and ten million arrangements for seven digits.

If you use a six-digit digital password on the host, there are a million arrangements. As we all know, the computer is running at a power speed and can be tried hundreds of thousands of times per second. If it is a supercomputer used by the country, it will be recorded in billions.

What Nick thought of was the simplest cracking method, which seemed very violent, so Nick named it, brute force cracking method, and he began to be uneasy. Should he do this? It seems a bit inappropriate to use his computer without the permission of the owner, but is it possible to ask the computer room to open a wide area network? It is absolutely impossible!

He was suffering in his heart. On one side, he was yearning and desire for the Internet, and on the other side, he was rejecting this kind of thief behavior. The two ideas were fighting each other. Finally, he thought about it and it was just a little bit of a loss. Finally, he made up his mind and Nick decided to do it.

Under the DOS system, there is no such function as brute-force cracking, so I have to write it myself. Fortunately, this is not a very complicated program, but it must be compiled in pure assembly language, because only this mechanical language can control the hardware of the other party's computer. In addition to this cracking, there is also a control platform. This platform is to find the port of the other party's computer, and after the cracking is successful, control the other party's computer platform.

Overall, the scale of this program is not large, but it is not small. If you start from scratch, this class will not work. So Nick first cracked the DOS system on the machine and made the source code of the DOS system. Nick had done it on his previous machine many times, so he quickly got it done. Next, he began to call out some of the required programs from the source code, and then wrote and added the programs he compiled in the middle. Finally, he integrated the brute-force cracking program into it, and an improved DOS system with brute-force cracking and remote control platforms was completed.

"Nick, what are you doing!" Nick was doing the final debugging, and suddenly Teacher Gander's voice sounded from behind, scaring Nick to death.

"I...I..." Nick, in a panic, couldn't tell anything about it.

"Oh, you're too slow, why haven't you entered the typing practice yet? Look, half of the class has passed, so if you can't do it, come to the teacher, just call 0 and 1 here."

Hearing this sentence, Nick finally put down the big stone in his heart, and quickly responded: "Yes...yes, I've done half a class, the teacher will help me!"

In order not to let Teacher Gande see anything, Nick groped and pressed the hot restart while he was talking, and the computer restarted.

Teacher Gande shook his head, then pointed to the blackboard and said, "Look at what is written on the blackboard, you don't have to worry about what that means, just press the letters written on the blackboard and type in, and then press the Enter key. The Enter key is this. You see it, that's it!"

He entered the program of typing again. Nick was so boring. Needless to say, he slowly typing the letters with a blank look on his face. At this time, Teacher Gande next to him rebuked: "Look at others, they have already typed very quickly. Look at your class monitor Thomas, who has fully studied and has started practicing the operation of the DOS system. Come on!"

"Yes, yes!" Nick hurriedly nodded and said yes.

Seeing Teacher Gande leave, Nick breathed a sigh of relief. Teacher Gande had already walked to Thomas and guided him with great enthusiasm and patience.

Continue to work, turn off the typing program, Nick tuned up the program that he had not finished just now. This time he was careful, while doing it, paying attention to Teacher Gande. Finally, after modifying one or two small mistakes, it can be used. I simply set up the system to load the new system when the system is powered on, and then restart it. After booting, the system loaded the new DOS system, which has not changed from its original appearance at all. If no one called the source program out to view it, he would not know that the system also has these two special functions.

Nick rubbed his hands with anticipation and began to enter a command. The brute-force cracking and intrusion control platform has been evolved into system commands, rather than software programs. Simply put, these two things have been completely integrated into the system.

An operation interface appears, and each computer on the LAN is displayed in letters, and there is an inaccessible computer. It can be imagined that this is the host. This host should not be placed in the computer room, but in the teacher's office outside the computer room. Only when the host is turned on can the computers here be connected together.
Chapter completed!