Ostatnio na blogu:
11.10.2023r.
It's been a while since the premiere of the latest processors for the AM4 platform. That is exactly why it
could be the best moment to build a powerful workstation based on this platform (as it comes to performance +
stability vs. price). PCI-e 4.0 NVMEs are cheap and have successfully passed the test of time, not to mention
DDR4 memory which is widely available and also relatively cheap.
It so happens that I have some AM4-based equipment left in the lab - it is a great opportunity to start a
new series about building the ultimate GNU/Linux workstation from scratch.
Have you ever wondered what really affects the speed of your computer? Is it a CPU? Or RAM? Not at all...
The perceived speed of your system depends mainly on the speed of your storage. I bet you have an intuition
that the feeling of using a computer with the latest processor and an old HDD would be very bad.
I will try to demonstrate how to push the speed of mass storage to its limits using a regular home
PC. I can assure you that this option is much cheaper than buying a new computer with PCIe 5.0 and
what's even more important - the result is much better!
The goal of this series is to present an approach that will lead to building a stable and powerful
workstation capable of achieving enormous storage speeds (~30GB/s and more).
All this using Free (as in freedom) production-ready, server grade technology - GNU/Linux.
Czytaj więcej
02.01.2023r.
This part of the SSH series will cover the configuration of the OpenSSH client.
Configuration sources
The ssh
client obtains configuration data from the following sources (in the following
order):
- command-line options,
- user's configuration file (
~/.ssh/config
),
- global, system-wide configuration file (
/etc/ssh/ssh_config
).
The client will use the first obtained value for each parameter. Configured options will be
used not only by the ssh
itself, but by a lot of other tools as well. That is, among others:
scp
, sftp
, sshfs
, git
, ansible
and any other
tool which uses the OpenSSH
library/suite.
Czytaj więcej
07.12.2022r.
Introduction
The Secure Shell Protocol (SSH) is probably the most used protocol by
devops/sysadmins around the world.
Most people think of the SSH as a method of accessing a shell on a remote host. The fact is that this is
just one tiny usage example of the SSH. Some other examples include:
- local port forwarding - connections to the given TCP port or Unix socket on the local (client)
host are to be forwarded to the given host and port, or Unix socket, on the remote side.
- remote port forwarding - connections to the given TCP port or Unix socket on the remote (server)
host are to be forwarded to the local side,
- local dynamic application-level port forwarding (SOCKS proxy),
- remote dynamic application-level port forwarding (SOCKS proxy),
- tunnel device forwarding between the client and the server (L3
tun
device) - Virtual Private
Network (VPN) tunnelling using the tun
network pseudo-device, allowing two networks to be joined
securely,
- accessing and/or mounting a remote filesystem.
Being familiar with all the above features is absolutely essential for any SSH user - both for the sake of
convenience and for the security.
Czytaj więcej
05.10.2021r.
In this article, I will introduce the interesting field of steganography. My goal is to show the basics of
steganography and to present a few techniques that will allow you to write clean, simple and, yet powerful
program.
What is steganography
Steganography is a practice of concealing a message within another message (or a physical
object) in such a way, that the message does not attract attention to itself as an object of scrutiny.
Whereas cryptography is the practice of protecting the content of a message alone, steganography is
concerned with concealing the fact that a secret message is sent.
Czytaj
więcej