Last night I saw something weird at Codenone. Actually, it was just a blank page returned from Drupal. PHP was set maximum memory limit to 64MB. It should be sufficient for a small site like Codenone. I noticed that the blank page often occurred on pages with comments. Below are my investigations.

1. Blank page will occur only on some nodes with some amount of comments.
2. There was no logs in Drupal.
3. There was no logs in virtualhost level.

Sometimes, OpenVPN for Win32 platform may refuse to start because all TAP-Win32 virtual ethernet adapters are in-used. In fact, this situation is just confusing state that OpenVPN is unable to open the adapters. Below is my solution.

One important thing that a Certificate Authority must have is Certificate Revocation List or so called CRL. The most common CA software is OpenSSL so you have to generate CRL in regular basis using OpenSSL command if your CA system relies on OpenSSL

According to my previous howto regarding ISPConfig and Courier's userdb, there are some problems with some crypted passwords. In particular, passwords may contain the delimiter (|) and the back quote (`) for evaluation in bash shell. As a result, the generated userdb will be invalid. Below is the script to fix these problems.

Camfrog is one of the most popular video chat system because of its performance and scalability. It is not as simple as you think. Camfrog is in press so often in Thailand. See below for some examples.

• Manager Online 1 2
• Daily News 1
• ThaiRath 1 2 3

RSA is one of the most well-known security infrastructure based on PKI. I'm talking about how to generate a key-pair to be used in applications.