Sysadmins be welcome!

Sysadmins of the North is just another technical blog, like so many others out there. Most posts are written in English, some in Dutch. For the most part, I write as it comes; posts may seem incoherently written sometimes (my apologies). Here on you’ll find all kinds of computer, server, web, sysadmin, database and security related stuff. Browse the latest posts per category here, search for posts, or make a selection from the categories menu.

Drop me a comment somewhere to say hi, or discuss about security, website or WordPress, MySQL optimization and performance, Windows Server and IIS web server topics.



Turn off swap

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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Open-Xchange Power-ing up

Open-Xchange stays on the takeover path: On stage live at World Hosting Day in Rust today Rafael Laguna (CEO, Open-Xchange) had the privilege of announcing that we’ve done it again – we’re merging with another pioneer in the open source and domain communities, Netherlands-based software company PowerDNS.

Read the announcement: Open-Xchange Power-ing up


Open-Xchange and Dovecot announce merger to create world’s leading open source messaging software provider

Yesterday, Open-Xchange AG and Dovecot OY announced the completion of a merger between the two companies. The combined company is now the world’s leading provider of open source cloud software for ISPs, telcos and cable companies providing one point of contact for an integrated solution – from email backend to application frontend. Under the terms of the merger, Dovecot has become a subsidiary of Open-Xchange.

Read the announcement: Open-Xchange and Dovecot announce merger to create world’s leading open source messaging software provider


PHP, MySQL and IPv6: still slow

Years ago, I noticed that PHP connections to MySQL were significantly slower over IPV6 (where a hostname has an IPv6 address or AAAA record), when no MySQL service is listening on that address. The connection is refused, and PHP has to fallback to IPv4. The fallback takes a significant amount of time. Too much time if you’d asked me. Unfortunately this fallback to IPv4 is still slow today…

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Redirect HTTP to HTTPS on IIS

When not to use a Rewrite…

A simple HTTP to HTTPS redirection is better left to the web server, with a simple redirection, than to a resource expensive Rewrite, be it on either IIS or Apache. A common use for IIS URL Rewrite is to redirect all HTTP requests to HTTPS. This situation is often better handled off by the IIS httpRedirect element.

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Software deployment through WDS

Install software packages during a Windows Deployment Services (WDS) deployment, without Microsoft Deployment Workbench (available in the Microsoft Deployment Toolkit, or MDT).

In my environment, I had to set up a new Windows Deployment Services (WDS) configuration for Windows 8.1 Enterprise. To roll out in our office (some 20+ workstations). I wanted to install some additional software at the same time, without using Microsoft Deployment Workbench, because I find the interface too slow. The solution? Read on…

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Monit monitoring on Ubuntu 14.04 VM on Hyper-V

Monitor websites and services with Monit on Ubuntu 14.04 LTS on Hyper-V, on either Windows Server 2012 R2 or Windows 8.1.

This post is about setting up a monitoring service using Monit. 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 set Monit up on a Ubuntu 14.04 VM, built on Hyper-V. And we use Monit to monitor several websites, and send out notifications on downtime.

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For my more novice Dutch readers, I started a new website project: A website dedicated to explain commonly used computer and internet techniques. Some of the topics include: What is DNS?, How do I edit wp-config.php through FTP?, How do I send an email with telnet?, and so on.

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DOSBox, play old games

Play really old games on Windows 7, 8, 8.1 with DOSBox

PC retrogaming how-to for 64-bit Windows

We all love old games. It’s a nostalgia thing from when we played those really old games on our 286 (or older, like an MSX) computer, either using floppy disks or cassettes/cartridges. There is nothing much sysadmin about this, it’s all about FUN! You all remember Airborne Ranger, Operation Wolf, Blues Brothers, Gunboat and The Lost Vikings, right? …

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Disable WordPress comments (how-to)

The WordPress comment system can be a bless for your blog, because of the user interaction. However, when the WordPress comment option is abused by spammers, it becomes a real pain in the “@ss”. With tens- or hundreds of thousands spam reactions, disabling and removing comments is the only way to go. Here is how to disable WordPress comments in both the WordPress Dashboard interface and in your MySQL database.

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Implement a highly available private cloud to host virtual machines

This document explains how to implement a highly available private cloud to host virtual machines from scratch.

Microsoft Partner Romain Serre published a document that describes how to implement a highly available private cloud to host virtual machines from scratch. For that he uses technologies such as Hyper-V, Scale-Out File Server, SQL Always On, Virtual Machine Manager, RD Gateways, Service Provider Foundation and Windows Azure Pack.

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logo Sysadmins of the North

Like, Share, Follow & +1

Did you know Sysadmins of the North is active on a number of social platforms? Social platforms include Twitter, Facebook, Google+ and Pinterest. Either as this website or on a more personal title. This post is to persuade you to follow and/or share posts with your friends, family, coworkers and other interested parties. So, if you read a post you found interesting, or a post that solved a problem you were facing, please share! :)

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Explicit Congestion Notification (ECN) slows down outbound connections

Windows Server 2012 is the first Windows Server version to enable Explicit Congestion Notification, or ECN, in the TCP stack. This is also known as ECN Capability. Explicit Congestion Notification is an extension to the Internet Protocol and to the Transmission Control Protocol and is defined in RFC 3168. ECN allows end-to-end notification of network congestion without dropping packets. ECN is an optional feature that may be used between two ECN-enabled endpoints when the underlying network infrastructure also supports it.

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Microsoft out-of-band security update MS14-068 (3011780)

and MS14-066 reissued, fixing TLS 1.2 cipher suites issues with Google Chrome

Yesterday evening, Microsoft released an out-of-band security notification MS14-068: Vulnerability in Kerberos Could Allow Elevation of Privilege (KB 3011780). This one is severe, and I recommend everyone to install this patch asap! It allows oridinary Domain Users to become Domain Admins, wh00ps…

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Denial of Service (DoS) Attack

Joomla! websites abused as open proxy for Denial-of-Service attacks

Joomla websites using the Googlemaps plugin for Joomla are actively abused as open proxy -or launchepad- for launching Denial-of-Service (DoS) attacks. Even though the vulnerability details in Googlemaps plugin file plugin_googlemap2_proxy.php were released over one and a half (1,5) years ago, I still see this abuse and DoS-attacks happening on a regular basis…

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Convert decimal to hex in bash?

A quicky for my archive, hexadecimal to decimal and decimal to hexadecimal in bash:

In mathematics and computing, hexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0-9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a–f) to represent values ten to fifteen. If you want to convert hexadecimal values to decimal and decimal values to hexadecimal, here’s how. All on the bash prompt…

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