On August 27, 2008, Jan Lehnardt gave a presentation (video, slides) on CouchDB to BBC web developers in London. As I listened to the recorded video, I realized that there was a lot of good information. In an effort to learn more, I have played it again, taken some notes, and shared them here. Most of the time I have paraphrased, but sometimes I have quoted (without using quotation marks). At the end of each note I list the time at which the subject begins.

CouchDB is a document database written in Erlang that is rapidly gaining more attention. I have been learning CouchDB lately, and as part of that process I gave a presentation, Introduction to CouchDB, at last weekend’s third annual BARcamp Chicago (once again organized by HostedLabs founder Jason Rexilius). You do not have to know how to program Erlang to use the database, but Erlang is pretty interesting, and the Erlang Workshop by Erlware co-founder etc. Martin Logan that opened the BARcamp helped me start to grok Erlang/OTP.

For last weekend’s BARcamp Chicago, I prepared a presentation titled Protect Your SSH Port (and Others) With fwknop. fwknop is an excellent Single Packet Authorization (SPA) implementation, written by Michael Rash, author of Linux Firewalls. When a firewalled machine is running the fwknop server a port can be temporarily opened from the outside using an fwknop client. This approach is better suited to long-lived sessions, such as those using OpenSSH or OpenVPN, as opposed to short-lived sessions like web browsing or using email. By keeping the port closed or filtered (stealthed) until needed, zero-day vulnerabilities in the service using the port can be protected against.

Here is how I remove old kernels from Ubuntu Server. It is not the only way, it is just how I currently do it. Why would you do it? Perhaps to save space. Is this the only way? No.

Something changed in Ubuntu Server from 7.04 to 7.10 with regards to the setup of the network components. The information in the present article is a follow-up to the Network Interface information in my previous article about 7.04. It describes the issues that I ran into, and how I finally worked around them.

I’ve recently become interested in using Ubuntu Server as the base Linux distribution for a project that I’m busy working on. My recent interest occurred when I learned that Ubuntu offered Sun Java, which I was considering using with some server software. It turns out I won’t use that software on this project, but as I’ve learned more about Ubuntu Server I’ve decided to stick with it anyway.

Ubuntu Server uses the same package archive as standard desktop Ubuntu. It starts off with a different subset of that archive, which has a nice variety of packages to choose from. The Ubuntu Server also has a Linux kernel that has been tuned to provide better performance and throughput for server applications. (It has other server-related features which are outside the scope of this article.)

This article describes one of many ways to do a basic installation of Ubuntu Server 7.04 as a VMware guest on a Windows XP host. It also gives some tips on how to perform some useful additional tasks, and it gives some links for further information. Please note that Ubuntu Server is set up to be run from the command line. A graphical environment is not included in the Server installation This allows the server to consume less memory and storage space. If needed, a GUI can be added later.

OpenVPN is an excellent, full-featured, free and open source SSL-based VPN solution that still isn’t very well-known, but that is changing. For example, late last year, Steve Gibson and Leo Laporte helped raise awareness of OpenVPN in some of their Security Now! podcasts. Other articles and presentations have appeared online and in magazines. OpenVPN is used in the commercial service personalVPN, which I use daily. I have also implemented OpenVPN for some of my consulting clients, and it has performed well.

There is now a book available on the subject of OpenVPN. It was released last month, and it is a good one:

OpenVPN: Building and Integrating Virtual Private Networks
by Markus Feilner
Packt Publishing Ltd
ISBN 190481185X

I’m a big fan of VMware Workstation. I’ve been using it for a few years to set up and run virtual machines for the purpose of building web database applications. Each virtual machine can represent a particular client’s server or client, or you can use them for projects under development.

I’m happy to announce that my article, “Use jEdit to Edit Your PHP,” has been published on the popular developer site, SitePoint.

My clients needed a secure way for their telecommuter employees to synchronize their contact manager software over the Internet with the contact manager application server in their office. After some research, I chose the open source, multi-platform OpenVPN as the solution. OpenVPN is a SSL VPN (Secure Socket Layer Virtual Private Network). It establishes an encrypted tunnel over the Internet, thus creating a private network over the public Internet.

PayPal phishing is a popular online method for thieves to trap the unwary. For example, say you have a PayPal account and you get an email from service at paypal dot com (email address modified to reduce spam). This is the common PayPal sender address, but it is no guarantee that the email is legitimate.

This project grew out of my desire to have a tool that would give me a line-by-line listing of a PHP script, with any included files inserted where they are included. I felt that this could help me better understand the flow of logic and variables in a script. I looked for and didn’t find such a tool, so eventually I decided to write my own.