Tag Archives for " linux "

Vulnerabilities in .NET Core, ASP.NET Core Could Allow Elevation of Privilege

Microsoft Security Advisory 4021279: Microsoft is releasing this security advisory to provide information about vulnerabilities in public .NET Core and ASP.NET Core. This advisory also provides guidance on what developers can do to update their applications correctly.

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Benchmarking WordPress, simple load & speed testing with ApacheBench

WordPress load testing with ApacheBench. ab is a small benchmark utility that comes with Apache. It’s a really simple HTTP load generating tool, ideal for a simple WordPress load & speed test. How fast does your WordPress site respond? How many HTTP requests per second can your server handle? These are questions on which ab can shed some light.

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MySQL InnoDB performance improvement: InnoDB buffer pool instances – Updated!

Are you running into MySQL load problems? Learn how how I tuned my MySQL servers for a heavy InnoDB workload, by configuring innodb_buffer_pool_instances. Dividing the InnoDB buffer pool into multiple instances improves Disk I/O. By doing so, you run your database and website more efficiently and faster. Here is a little help for you.

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Recursive scp and symlinks

Recursive scp without following symbolic links. TL;DR: when using recursive scp, symbolic links aren’t preserved and are copied as if they are normal directories. So you have to look for another solution to recursively transfer symlinks over ssh. Here is one: Tar over ssh!

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Install Varnish Cache on CentOS 6.7

In this article I’ll show you how to install Varnish Cache on CentOS, version 6.7 in this case. Varnish is a web application accelerator also known as a caching HTTP reverse proxy. You install it in front of any server that speaks HTTP and configure it to cache the contents. Because Varnish Cache is really, really fast, web applications like WordPress, Drupal and Joomla can […]

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Install Elasticsearch on CentOS 6.7

How to install Elasticsearch on CentOS 6.7. Elasticsearch is a highly scalable open-source full-text search and analytics engine. It allows you to store, search, and analyze big volumes of data quickly and in near real time. In this article we’ll go over the steps to install Elasticsearch on CentOS 6.7.

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Generate pseudo-random passwords with OpenSSL

OpenSSL comes in handy when you need to generate random passwords, for example for system accounts and services. In this short post I’ll give you a quick example on how to generate random passwords with OpenSSL in Linux (Bash), Windows and PHP…

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BIND 9.x vulnerable for remote Denial of Service through a magic packet

A vulnerability in BIND, and all it takes is just one tiny little packet… BIND 9.x is vulnerable for a remote Denial of Service, where a tiny magic packet can cause BIND 9.x to stop and exit named with a REQUIRE assertion failure. All the attacker needs to send is a specially – and deliberately – constructed packet to exploit an error in the handling […]

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Tunnel RDP through SSH & PuTTY

How to tunnel Remote Desktop over SSH with PuTTY? Have you ever been in a situation where you needed to perform remote administration on a Windows Server, and the RDP port 3389 is blocked on a firewall? You can tunnel RDP over SSH with PuTTY. This particularly comes in handy when there is no VPN available to the remote network…

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Turn off swap

How to turn off swap in Linux. Not every Linux server I administer needs to have a swap partition and to start swapping. For instance, the MySQL servers I maintain all have more than enough RAM on board to do their work. Yet, when a swap partition is enabled Linux starts swapping, which may degrade MySQL database performance…

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Monit monitoring on Ubuntu 14.04 VM on Hyper-V

Monit monitoring for websites and services, on an Ubuntu 14.04 LTS VM, hosted on a Windows Server 2012 R2 or Windows 8.1 Hyper-V. This post is about setting up a Monit monitoring service. Monit is a free and open source service monitoring application which can perform various event-based actions. Monit can send email notifications, restart a service or application, or take other responsive actions. We […]

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How to restore a deleted Open-Xchange context?

How-to restore, or recover, an accidentally deleted OX context. If you’ve accidentally deleted an Open-Xchange context (contextid), then that is bad… Here is how to recover a deleted OX context and filestore… Assuming you make Open-Xchange backups of course.

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Convert decimal to hex in Bash?

How to convert decimal to hex in Bash, hexadecimal to decimal and timestamps to dates. Use Linux Bash shell to convert decimal values to hexadecimal, and vice versa

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Sysadmins of the North goes global!

How to set up a global Geolocation DNS load balancing Varnish Cache Content Delivery Network with Bind9, geo-ip database, Varnish Cache and DigtalOcean. DIY High-Availability for your website!

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Old-school: Unix wildcards gone wild

DefenseCode’s Leon Juranic released an article explaining an old-school hacking technique: Unix wildcard poisoning attacks. No ASLR bypass, ROP exploits or 0day remote kernel exploits, but if you wonder how basic Unix tools like ‘tar’, ‘chmod’ or ‘chown’ can lead to full system compromise, keep on reading.

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