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Recently I was making a simple web form to allow admins of a site to create accounts for new users. The admin enters the email address of the new user. When the form is submitted, a random password is generated and emailed to the user. (This is for privacy/security: it prevents the admin from knowing another user’s password.) However, the admin needs to enter their own password when submitting the form. In other words, the email address and password fields in the form are for two different accounts.

Here’s the situation: your colleague is working on laptop C. They need to get into server A. Server A is behind a firewall, and can create outbound connections, but inbound connections are not allowed. You have access to an internet server B, but you don't want to allow full shell access on there to your colleague.

The TotoLink LR1200 is a fairly cheap WiFi access point and 4G/ethernet modem router available in Asia. It's also known as the Zioncom AC1200. It has two web interfaces: a standard interface with all the features available, and a simplified version designed for mobile devices.

By default, phpMyAdmin is missing a number of useful configuration options. When you install it from source, you can set these options by editing /path/to/phpmyadmin/config.inc.php. However, Debian and Ubuntu package up phpMyAdmin and store things in a slightly different place. This makes installation, update and maintenance much more convenient, but does make things slightly more confusing when you want to set custom options.

When reviewing code, a simple first step in checking that it doesn’t include any errors is to run a syntax check. In this post, I outline how to set up tools to scan all the code in a directory for syntax errors, and how to run this scan automatically when committing your code to git. For simplicity’s sake I am assuming that you are running Ubuntu, but the principles apply to any development environment.

PHP

The command line version of PHP (package php7.x-cli) allows you to syntax check a single file:

In this post, I describe how to set up spam filtering rules based on the country that an email was sent from, using SpamAssassin. These notes are based on Debian Bookworm, but the principles are very similar for other versions of Debian and Ubuntu. If you run a mail server that primarily only receives mail from a few countries, this guide should be very helpful to you in the fight against spam.

Update: the information below is a bit outdated. As of December 2023, I recommend using https://github.com/phd/chromium-repo instead, as it’s easier to set up and more reliable. Phd’s repository is based on the packages from Linux Mint.

In this post, I provide instructions on setting up automatic WordPress security updates for multiple sites on UNIX-based servers.

The very commonly used mysql_* and ereg* PHP functions were removed in PHP 7. For very large codebases, refactoring the code to remove them just isn't practical. To that end, we have developed a compatibility library to enable existing websites and PHP scripts to keep running under newer PHP versions.

There are fundamental differences between PHP scripts that are run by a web request, and those that are run from the command line. One of the main ones is that the environment settings will be completely different, including the path. Every few years I forget this and it comes back to bite me.