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Archives pour la catégorie ‘Logiciel’

Knockd : Sécuriser vos connexions

01/06/2020 Aucun commentaire
source: http://www.debianworld.org/securite.knockd

Knockd est un petit daemon qui autorise ou non une connexion à votre serveur. Pour cela il écoute les ports de votre machine et attend une séquence bien précise de connexions sur les ports que vous avez définis. Si la séquence définie est exécuté dans le bon ordre, le daemon va ouvrir le port et permettre une connexion pour un temps déterminé sur le port ssh par exemple. La séquence peut utiliser des connexions TCP ou UDP ou les deux.

Ainsi, d’un point de vue extérieur le serveur n’a aucun port d’ouverts exception faite pour les clients qui ont la séquence “magique”.

Lire la suite…

Thumbnail Generation PHP Memory Limit NextGEN Gallery

28/05/2020 Aucun commentaire

Source: Visser Labs Blog

When uploading a set of admittedly large images using NextGEN Gallery to my WordPress site I exceeded my web hosts default memory usage allocation for PHP applications. The error was:

Follow thumbnails could not created. sample.jpg (Error : Exceed Memory limit. Require : 80.65 MByte)

This issue can be resolved by increasing the memory usage allocation at a per-plugin level for PHP applications that require more grunt than others. It’s quick and easy!

  1. Open an FTP connection to your root WordPress directory
  2. Open /wp-content/plugins/nextgen-gallery/lib/gd.thumbnail.inc.php with your favourite text editor (e.g. UltraEdit, etc.)
  3. On line #168 un-comment (remove the //) from before @ini_set('memory_limit', '128M');
  4. Save and upload changes
  5. Delete image/s that failed to generate a thumbnail and re-upload using NextGEN Gallery’s standard Upload Images feature

If you find 128MB is too ‘conservative’ this can be increased again to any figure of your liking, I find 128MB appropriate for most commercial and personal usage but if you’re a HD photographer then you’re going to hit this limit very quickly… that’s it!

 

Categories: Logiciel Tags: , ,

How To Use Apache JMeter To Perform Load Testing on a Web Server

23/05/2020 Aucun commentaire

Introduction

In this tutorial, we will go over how to use Apache JMeter to perform basic load and stress testing on your web application environment. We will show you how to use the graphical user interface to build a test plan and to run tests against a web server.

JMeter is an open source desktop Java application that is designed to load test and measure performance. It can be used to simulate loads of various scenarios and output performance data in several ways, including CSV and XML files, and graphs. Because it is 100% Java, it is available on every OS that supports Java 6 or later.

 

Prerequisites

In order to follow this tutorial, you will need to have a computer that you can run JMeter on, and a web server to load test against. Do not run these tests against your production servers unless you know they can handle the load, or you may negatively impact your server’s performance.

You may adapt the tests in this tutorial to any of your own web applications. The web server that we are testing against as an example is a 1 CPU / 512 MB VPS running WordPress on a LEMP Stack, in the NYC2 DigitalOcean Datacenter. The JMeter computer is running in the DigitalOcean office in NYC (which is related to the latency of our tests).

Please note that the JMeter test results can be skewed by a variety of factors, including the system resources (CPU and RAM) available to JMeter and the network between JMeter and the web server being tested. The size of the load that JMeter can generate without skewing the results can be increased by running the tests in the non-graphical mode or by distributing the load generation to multiple JMeter servers.  Lire la suite…

ORC – Un réseau de stockage cloud, anonyme et décentralisé reposant sur Tor

20/05/2020 Comments off

Counterpoint Hackerspace, une bande de geeks localisée à Roswell dans l’état de Georgie aux États unis, a eu l’excellente idée de mettre au point un outil permettant de stocker sur Tor des fichiers, un peu à la manière d’un espace “cloud”, mais avec tous les avantages que Tor peut apporter : anonymat, décentralisation et gestion par la communauté. Lire la suite…

Categories: Logiciel, Sécurité, Système Tags:

High Sierra Problems: How To Fix The Most Common Macos Issues

19/05/2020 Comments off

The excitement of installing a new version of macOS, especially if its a High Sierra 10.13, is only tempered by the possibility of it not working properly or not being compatible with the apps you use most.

Before you begin upgrade to MacOS make a bootable backup

If you haven’t started the process of upgrading yet, check if the Mac is compatible with macOS High Sierra and make a bootable backup. 

Do it now, before you do anything else. If things go disastrously wrong at least you’ll be able to boot from macOS’ Recovery partition and migrate all your data back to your Mac. You can use any backup tool you like – Apple obviously favours Time Machine, but you don’t have to use it. You can use, for example, Get Backup Pro, which comes with your Setapp subscription. Don’t have a Setapp subscription? Click here to sign up.

Common MacOS High Sierra Problems

While most new versions of macOS are relatively problem-free, it’s not unknown for users to have issues – particularly with a beta or .0 release. Thankfully most are easy to resolve. Here’s how to fix the most common High Sierra issues.

High Sierra Installer Won’t Download

If you’re trying to download the macOS High Sierra installer, you’ll need to have signed up to App Store. If you’ve done that, and managed to start the downloading process only for it to fail, force quit the App Store app.

  1. Press Cmd-Alt-Esc or go to the Apple menu and choose Force Quit.
  2. Select the App Store app and confirm you want to force quit.
  3. Re-launch the App Store and try downloading again.

Macos High Sierra Won’t Install

If the download completes successfully but the installation doesn’t finish, force quit the installer using the same procedure as above. 

  1. Restart your Mac
  2. Launch the App Store app and go to the Purchases tab. 
  3. Find macOS High Sierra and click Install. 

If that doesn’t work, try deleting the downloaded installer (it’s in your Applications folder) using CleanMyMac and download it again.

If you have a copy of macOS Server in your applications folder, that may be the root of the problem. Delete it and try again.

Lire la suite…

Categories: Logiciel, Système Tags: ,