Administration Section
About digitalization and more, and not so much. Life as a Service ( ЖКУ) or in English 'Life as a Service' (LaaS) has already found expression in the minds of several individuals or groups of people: here it has been considered from the perspective of overall life digitalization, turning all its aspects into services and the required new political system of capitalocommunism, and here […]
This article is about how to set up a modern mail server. Postfix + Dovecot. SPF + DKIM + rDNS. With IPv6. With TSL encryption. Supporting multiple domains - part with a real SSL certificate. With anti-spam protection and a high anti-spam rating from other mail servers. Supporting multiple physical interfaces. With OpenVPN, connected via IPv4, and which […]
A long time ago, I wrote my first post on Habr. This post was dedicated to a quite interesting problem, namely steganography. Of course, the solution proposed in that old topic cannot truly be called steganography in the strict sense of the word. It's just a game with file formats, but nonetheless, quite an interesting game. Today, we will try to delve a little deeper […]
A Brief Introduction Steganography, if anyone remembers, is the hiding of information within some containers. For example, in images (discussed here and here). You can also hide data in the metadata tables of the file system (this was written about here), and even in the service packets of the TCP protocol. Unfortunately, all these methods have one drawback: to discreetly 'inject' information into […]
Introduction Greetings. Not too long ago, when I was studying at university, I had a term project for the course 'Software Methods of Information Protection.' The assignment required creating a program that embeds a message in GIF format files. I decided to do it in Java. In this article, I will describe some theoretical aspects, as well as how this small program was created. Theoretical Part GIF Format GIF (Graphics Interchange […]
Polish researchers have proposed a new method of network steganography based on the peculiarities of the widely used TCP transport layer protocol. The authors believe that their scheme could be used, for instance, to send hidden messages in totalitarian countries that impose strict internet censorship. Let’s try to understand what the innovation consists of and how useful it really is. First, we need to define […]
Hello, Habr. I would like to introduce you to a small project on steganography that I created in my free time from studying. I made a project on the covert storage of information in the file system (hereafter FS). This can be applied for stealing confidential information for educational purposes. The experimental sample chosen was the rather old Linux file system ext2. Implementation Considerations for Implementation If one can 'really dig deep' […]
This article is the second in the series 'How to Take Control of Your Network Infrastructure'. You can find the content of all articles in the series and links here. Our goal at this stage is to bring order to the documentation and configuration. By the end of this process, you should have the necessary set of documents and a network configured accordingly. Right now we […]
This article is the first in the series ‘How to Take Control of Your Network Infrastructure.’ The content of all articles in the series and links can be found here. I fully acknowledge that there are a sufficient number of companies where a simple network being down for one hour or even one day isn’t critical. Unfortunately or fortunately, I have not had the chance to work in such places. […]
Table of contents for all articles in the ‘How to Take Control of Your Network Infrastructure’ series and links. Currently, 5 articles have been published: Chapter 1. Retention Chapter 2. Cleaning and Documentation Chapter 3. Network Security. Part One Chapter 3. Network Security. Part Two Supplement. On the three components essential for the successful operation of IT A total of about 10 articles will be written. Chapter […]
This short post is an important addition to the series 'How to Take Control of Your Network Infrastructure'. You can find the content of all articles in the series and links here. Why doesn’t it work? If you try to apply the processes and solutions described in this article in your company, you will realize that it may not work for you. For example, let’s […]
This article is the fourth in the series 'How to Take Control of Your Network Infrastructure'. You can find the content of all articles in the series and links here. In the first part of this chapter, we looked at some aspects of network security in the 'Data Center' segment. This part will be dedicated to the 'Internet Access' segment. Internet access security is undoubtedly one of the most complex topics […]