Sysadmin

Various guides and articles about servers and products such as haProxy and nginx.

Installing required WordPress extensions for PHP 8.

A guide on how to install certain PHP 8 extensions for WordPress.

How to stop Fail2ban from causing high CPU usage.

A tutorial on how to stop Fail2ban from going haywire and hogging your server’s CPU.

How to test your HAProxy configuration file.

A quick guide on how to validate your HAProxy config file before you attempt to restart it.

Nginx: SSL_do_handshake() failed… and that’s OK!

The SSL_do_handshake() failed error is nothing to worry about in most cases.

MySQL: Extract Year and Month from Date column.

This is a short guide on how to get the year and month from a date column in MySQL.

Create a new Sudo User on Ubuntu.

This is a quick guide on how to create a new sudo user on Ubuntu.

How to disable the Nginx access log.

This is a guide on how to disable the Nginx access log.

Test Nginx configuration file.

This is a short guide on how to test your Nginx configuration file without restarting your web server.

How to get the current PHP version.

This a guide on how to check the current version of PHP.

Nginx: Force HTTPS.

This is a guide on how to force HTTPS on an Nginx web server.

MySQL: Server sent charset (255) unknown to the client.

This is an issue that occurs because MySQL 8 changed its default charset to utfmb4.

MyISAM locking explained.

The other day, some of our users reported that saving data had become extremely slow. In some cases, forms were taking up to 15 seconds to submit.

Preventing X-Forwarded-For spoofing in HAProxy.

This is a guide on how to prevent IP spoofing with HAProxy.

The Facebook crawler DDOS.

Facebook’s crawler is an untamed beast and if you are not careful, it will cause you a lot of problems. Especially you use a lot of story images.

Renaming a file with the Linux command line.

This is a short beginners guide on how to rename a file using the Linux command line.

Speeding up HAProxy SSL with multiple CPU processes.

This is a guide on how to speed up SSL on HAProxy. In this post, I will show you how to dedicate specific CPU processes to HTTP and HTTPS traffic.

Blocking POST, TRACE and PUT requests with HAProxy.

A short guide on how to allow or deny certain HTTP methods using HAProxy.

Prevent unwanted domains from forwarding to Nginx.

A short guide on how to prevent spammy domains from forwarding to your Nginx web server.

PHP-FPM settings tutorial. max_servers, min_servers, etc.

A guide on selecting the correct www.conf settings for PHP-FPM.

Guide: Upgrading HAProxy from 1.6 to 1.8 on Ubuntu 16.04.4 LTS (Xenial).

This post details the steps that I took to upgrade HAProxy from 1.6 to 1.8 on Ubuntu 16.04.4 LTS (Xenial).

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