Category: Blog
OpenSSL is a full featured tool capable not only to generate keys and certificates, but also to provide every facility a PKI must have, such as indirect CRL and OCSP responders: these features, along with certificate's best practices such as the Certification Practice Statement (CPS), publishing CRL Distribution Points URL, OCSP Responders URL, CA Issuers URL, are the topics of the OpenSSL CA tutorial - A full-featured openssl PKI.
As we saw in our post on Symmetric And Asymmetric Cryptography, asymmetric key pairs can be used to encrypt and digitally sign documents, but have a huge shortcoming: since they are just keys, they don't provide the metadata necessary to enable people to securely identify their owner. As we saw in the post on GNU Pretty-Good Privacy, GPG addresses this shortcoming by wrapping the key into a container object (the GPG key) that also embeds some metadata about the owner of the key. Of course also the IETF addressed this problem, defining the standard for X.509 certificates (currently X.509v3). X509 Certificates Howto & Public Key Infrastructure Tutorial explores X.509 certificates and how they are trusted by the means of a Public Key Infrastructure.
Every system administrator daily use SSH to connect to remote systems and perform they daily tasks: the very most of the time these consist into typing statements on the terminal or copying files from and to the remote system, or again running remote commands, but SSH is much more than this: it not only provides additional facilities such as agent or forwarding, port forwarding and X11 forwarding, but it has also a subsystem that can be exploited to provide SSH secured services such as SFTP.
The goal of the "OpenSSH Tutorial - The Ultimate SSH Guide To Understand It" post is to tell you what historically drove us to SSH, describe the protocol suite in detail and provide a thorough tutorial on using all of these facilities.
This post is based on Red Hat Enterprise Linux 9, but the same concepts apply to the very most of the Linux distributions.
Every time you interact with a computer, either using a command line or graphically, you are using a console. Despite its ease of use, a console must address and solve a lot of compatibility problems, for example properly interpreting control characters that may differ from terminal to terminal.
Being able to customize settings such as locale and keyboard layout is the basis, but it is not enough: , having at least a basic understanding of how a console works under the hood is certainly a valuable skill that lets you quickly and easily address some uncomfortable situations that sometimes arise, especially when connecting to old systems that, in the face of security best practices, for various reasons after decades are still there without being updated, maybe because very are running obsolete services that are not compatibles with up to date operating systems.
The "Linux Console Essential Virtual Terminals Terminal Emulation and configuring locale" post is meant to provide you everything it is necessary to know to solve the most common problems that may arise concerning the Linux console and locale.
Python enables you to easily serialize objects as either JSON or YAML: very often it is very convenient to leverage on these features exploiting them to enhance your own object. YAML serialization comes almost for free if you derive your classes from the YAML object, whereas automatic instantiation of objects from a YAML document requires a little bit of work and leverages on YAML tags. As for JSON serialization, it is bloody useful and enables you to quickly and easily serialize the contents of your objects into JSON documents that can be exploited for example to interact with or to develop a REST API.
This post, Python Serialization as JSON or YAML exploiting YAML TAGS, shows you how to develop a Python package that provides such kinds of objects. As usual we take particularly care of the code style, using a very clean and portable design and adhering best practices.
It is almost impossible not having heard about or not having used LVM: it is one of the pillars of every Linux distribution from decades ago. Almost everyone using Linux has used it to create or modify the basic storage structures of its Linux system. The trouble is that very often people are focused on the specific task they are onto, and neglect the time to investigate its amazing features. The goal of LVM Tutorial - A thorough howto on the Logical Volume Manager is to provide an easy yet comprehensive explanation on the most interesting features of LVM that it is very likely you will need to use sooner or later.