<Advantages> 1. A good environment for practice - You can quickly build a stable practice environment through Discord without the need for environment setup/setting issues that are always indispensable when studying IT. In particular, lectures that were filmed a long time ago are difficult to set up, but this lecture has no such problems at all. 2. Solid structure from basics to completion - They kindly explain everything from basic Linux commands to mock hacking report writing. Even those who are not familiar with Linux can easily take the lecture. (However, you will need to practice a lot to get used to the Linux shell environment, but I think you can learn even that quickly with redraccoon's raccoon city content.) - Those who already have some knowledge of web hacking or service hacking can organize it by following the flow of the lecture. In particular, they provide a guidebook in addition to the lecture, and if you do not have enough time to watch the video, the guidebook is detailed enough to follow the content just by following the guidebook. 3. Content not available on the market - In the case of Windows, there is no content related to vulnerability diagnosis on the market compared to Linux, but it is covered here, so it was good to study. 4. Various practice problems - You can practice various environments by creating 10 target machines and even doing self-tests. In particular, since it is a high-quality machine that can be solved in various ways rather than a general CTF, if you want to get a job related to mock hacking, you can write a mock hacking report and receive feedback. 5. Quick feedback - They give quick feedback through Discord. Although neither of them are in Korea, if you ask a question on Deco, you will get feedback so fast that you will wonder if they are in Korea. <Disadvantages> 1. Price - Considering the content of the lecture, it is not expensive at all, but it is not a price that you can just take a look at with a light heart. In my case, I decided to buy it after reading the table of contents, but I thought about it again after seeing the price. Of course, at this point, I do not regret buying it at all, and considering the content, it is really cheap. => Overall Review: This is a very high quality content, so if you are hesitant to buy it, I recommend eating a few less chickens and then buying it. ㅎㅎ