When he walked into the classroom, many people looked over. The tension that Nick suppressed in his heart suddenly burst out. In front of everyone, he had to hold on to the podium. Just this short distance was more difficult than a three-kilometer long-distance race.

Finally I could hold on to the podium in front, and my heart was a little bit more solid, but the oppression brought by the hundreds of pairs of eyes opposite me felt a little dizzy, making Nick breathless.

Opposite was a large group of people from Black Crow, with pairs of eyes, Nick's head was in chaos, and even his thinking became dull. He didn't know where to look. He had to lower his head and force himself to pull a hoarse voice, "Okay, start class now!"

Below was a rumbling sound of flipping through books, and some people even took out recording equipment. In the past, most people had difficulty understanding in class, so they had to record the content of the teacher's class and go back and digest it slowly.

Nick was so nervous that he felt so confused. There were so many people opposite him, living people, a large area of ​​tension, which made the lyrics he had prepared before flew outside the nine-night clouds!

It seemed like I could remember that, next, it seemed that it was time to open the textbook and start the lecture. The textbook! Nick felt cold. He was nervous and rushed before coming. He forgot to bring such an important thing, so he had to stutter: "Where have you... you guys?"

Fortunately, a student responded: "Don't serve attack!"

The classroom was simulated so realistically, and there were academic problems. Nick recalled it slightly. Although he knew it very clearly, he still had to organize the language. He began to explain carefully: "Don't-service attack, referred to as DoS, the full name of DenialofService,... is a common...hacking behavior. This attack is like throwing apples around,

A small burst of laughter came from below!

"Stuff the network with a pile of rotten apple-like data packets, so good apples will turn into rotten apples, and then the network server will really turn into garbage cans..."

The college students below looked through the textbooks one after another. One of the college students raised the textbook and said: "Teacher, this is not written in the textbook. What the textbook says is to send a packet request with a false source address, which makes the network server full of information waiting for reply, consumes network bandwidth or system resources, and makes the network or system service load too heavy, leading to incomplete reception of data packets until they are paralyzed and the normal service is stopped!"

Facing the hundreds of pairs of eyes in the audience, although he was a little nervous, his nervousness began to numb. As for not taking the textbook, Nick said perfunctorily: "Well, that... don't worry about what the book says, just listen to me!"

After a lot of discussion, there has never been a professor who is so crazy that he dares not to care about textbooks, and this professor dares not even bring lecture notes or textbooks!

Nick on the stage cleared his hoarse voice and explained: "Sometimes, in order to improve the effect of the attack on throwing apples, they will join forces with many people who throw apples. In this way, it is even more difficult to prevent if the apples are bitten by whom, and if they don't know where the apples were thrown from! In addition, a celebrity once said, you can't throw me away, but you can't stop me from throwing you away. This shows that the other party cannot stop you from throwing him unless he goes offline. Now let's talk about the key points of throwing apples. When throwing apples, you should pay attention to the following points. First, pee first. When you are urged to pee, you often can't walk away!"

Nick's personal experience!

There was laughter in the big classroom.

"Second, prepare for the apple, of course, you have to bite it first. Add a dead loop after the srim function, which not only can hide the address, but also improve the blocking effect. Third, Apple transmitters are best done by yourself. It is recommended to use assembly language, pay attention to mastering the time function, and fourth………………………”

The college students below all became interested. This was just teaching people how to attack the server, so they could practice it when they go back.

A student asked: "Professor, what does this have to do with the dense narrative of the textbook's defense measures?"

"This is what I'm going to talk about next. You can tear off that page and throw it directly into the garbage dump. In fact, there is no need to make it complicated. This is very simple. There should be a bad apple defense technology. First, it is the Apple's actual function, referred to as SDW - a data packet identification system. It screens out the apples with the fuer field. Any trace of bite is not acceptable. Second, transform the garbage can and change the barrel mouth to a shape that cannot be blocked. Often, use the SRF port and ESQ port......"

I was at a loss on the podium and didn’t know what to say on the podium. Now when it comes to professional knowledge, there is a lot of things to say. Because I am very familiar with it, I think constantly, and the explanation can be continuous, and the tension begins to gradually disappear.

Before he knew it, half of the class had passed. The 300 college students below listened with relish and had to respect the professor's wide range of knowledge. He not only combined the knowledge explanations of many subjects such as storage principles, programming, databases, etc., but also quoted the latest technology at the moment, and explained all this as a whole. The college students below began to slowly close the textbook because they felt that they did not need this thing.

"Now we talk about IP return tracking algorithm" Nick wrote the title on the blackboard.

There was a sound of notes below. Everyone took notes very seriously and listened to the class, for fear of missing a little. Even if they didn't understand the previous class, they could understand what the professor said. It would be more appropriate to describe their hearts as hungry and thirsty.

"Due to its own defects, the PPM algorithm cannot return and track DDoS attacks well, just like we cannot catch up with cars on a bicycle in general. But there is no absolute truth in this world, so I will teach you how to chase cars on a bicycle." Seeing that the students below stretched their necks, they seemed to be very interested in this thing.

"The first method is to dig a hole in the fuel tank of the car before the race, so that the car keeps draining oil while driving. Since the router randomly tags the data packet with probability p, we can take advantage of the opportunity to write the forged mark information into the header of the host's fuel tank - the packet's header (usually the Identifier field), so that the data packet is not marked by the router it passes by. After reaching the target host, it will constantly copy itself, consuming a lot of system resources. Hehe, doing so will slow down the host and even stop running. Then we can easily surpass him by riding a bicycle, and we can also bring our girlfriend with us."

There was another chuckle in the classroom.

"The second method-" Nick paused mysteriously, and saw the interest below rising, and then he continued: "It is to secretly change the signposts before the competition... Generally speaking, in order to save storage space and reduce the burden on the network, the host often uses edge mark compression and shard storage technology. Then we can write a small program to combine shards that do not belong to the same data packet, so as to generate the wrong side path. In that case, our car guys will go the wrong way, and you will be the champion, and you can also have a comfortable cup of coffee in the cafe on the side of the road."

The professor explained vividly, with many invasion cases and real defense methods. The college students below felt immersive. When they talked about the wonderful things, they couldn't help but laugh. Applause was something that would never happen during class. Even the students who usually took their headphones and listened to the class carefully.

Among the large area of ​​black crows below, one of the college students raised his hand.

Nick also followed the answer, as he saw the professor in class before, waved his hand to signal the student to stand up. This was a student wearing glasses and very knowledgeable temperament. The college student stood up and asked, "Is there any possible security problems with the computer hardware?"

Nick touched his beard and said, "This is not information security content, it is the scope of hardware defects!"

The college student said disappointedly: "Oh, it turns out to be another subject, so forget it!"

"Most of this hardware defect refers to design errors, and related problems that arise. These hardware defects are often exploited. The most famous ones include the CDM frequency of SIR motherboards and the main chip defect of ASL. Although it has not been announced, veteran hackers and computer security personnel should know it."

"So, are you also a computer security person?"

"Well, this... is... is... is... is! If you don't talk about this, ah, whoever has any questions can ask, and any questions can be done!"

Before I knew it, the bell rang, and the college students below never felt that class time passed so quickly.

"Okay, that's all for today, let's finish the get out of class!" After these dozens of minutes, Nick was completely detached from tension. He didn't take anything and was about to leave empty-handed.

"Teacher, let's talk for another ten minutes, okay?"

"Yes, talk for another ten minutes!"

"Ten minutes, ten minutes are enough!"

The strong demands from college students are already buzzing

The whole set of opera performances, Nick scratched his head, and then said, "Okay, let's talk about it for another ten minutes. Let's talk about the content of the textbook first. In order to let you better understand the content of the whole book, I will talk about some general categories for you. The so-called "There is a shield, and there is no shield that cannot be broken in the world. I think the textbook should be exactly the opposite of what I said. This is the mistake of the course. The key to understanding this course is here. Secondly, understand "Data Science". All attack defenses are derived around the essence of data..."

Ten minutes passed, the class bell rang, and the college students below seemed to be reluctant to leave, but they had to let the professor leave.

Jem, who re-engineered this information security, sorted out his notes like a treasure. To be honest, he had so many classes that he had taken, he started to enter the class tepidly after the professor came, and then the students below listened to the class with a stern face, which was a bit like the listening assembly line, and then entered the next class. There was never passion in the class, and this class was really exciting, especially the professional and stimulating hacker intrusion, which made people feel refreshed. Not only that, he also explained the computer completely anatomically, and it was impossible to guess what class this professor was taking, no matter which course the knowledge of the course was covered, as if he knew everything about computers, and he could pick up any knowledge at will.

The college students around him were dispersing. Jem slowly closed his notebook and stared at the blackboard. He knew that the person he was about to graduate was so far away from the peak. If the professor was such a class, maybe this university could be studied for a few more years...
Chapter completed!