SSH and Port Knocking

Nov 13, 2016 in Linux

It turns out that SSH brute-force attacks, dictionary attacks or combinations of those are daily routines nowadays. Server logs are quickly filled with login attempts, in the hopes that one of them is right. The best prevention against these kind of attacks is to - obviously - have a secure password, or …

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GPG Cheatsheet

Oct 03, 2016 in Linux

GnuPG (GNU Privacy Guard) is a tool for encrypting and signing data. It is a completely free implementation of the OpenPGP standard (defined by RFC4880), which is also known as GPG. This post contains a brief overview of the most important commands you probably have to use when working with …

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Postfix and SMTP Relaying on CentOS 7

May 01, 2015 in Linux

One way to transmit mail within a local server is by sending them directly through third party mail servers on the Internet using the SMTP protocol.

Postfix is a free and open-source mail transfer agent (MTA) and available in most Linux distributions (including CentOS 7!).

This guide will outline the …

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Using Git to Manage a Live Site

Aug 09, 2014 in Linux

Uploading files to production level after every change in code can be quite a hassle. Most people would use an automated deployment system instead of doing it manually. We can create an automated deployment system ourself by just using a version control like Git, which would also only take a …

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