By far the most popular set of articles I have written is my Raspberry Pi Email Server tutorial. Clearly, there are plenty of people who don't like relying on freemail providers like Yahoo, Outlook and Gmail for a variety of privacy and security reasons. However, there is one major drawback of hosting your own email server: if your server is taken offline for maintenance, or your internet connection is interrupted, then incoming email can not be delivered and may bounce. This tutorial will describe how to set up another server to act as an MX backup. The backup server will be hosted on a separate internet connection with a different WAN IP address, and have a lower priority than your primary mail server in your Mail Exchanger (MX) DNS record. When your primary server is offline other MTAs will send email to the backup instead, and the backup will hold them until your primary mail server comes back online, and then deliver them. No more bounced emails. The biggest challenge when setting up a backup MX is convincing a friend or family member to allow you to run a RasPi or some other server on their network; the rest of the setup is a breeze compared to the full mail server installation described in the main tutorial, because fewer components are required (just Postfix). This guide is written for Debian and its derivatives (Raspbian, Ubuntu etc.) but since a basic postfix installation is more or less the same across different distributions you should be able to use it for any distro. My backup server runs openSUSE.

This tutorial will show you how to configure a caching BIND9 server on your local network, and configure an OpenWrt router to use it. This should result in slightly quicker DNS lookups, but to be honest, you may not notice a huge difference (my DNS lookups now take 30% less time, but I don't think this has made page loading noticeably faster). Here are a few situations where it could be particularly worthwhile:

• You have a large LAN with lots of clients, and you want to take some load off your router
• You are using something like modsecurity's real time RBL lookups and you want to reduce latency
• Your ISP's nameservers are slow but you would still like to use them
• You are a curious soul and you want to learn about DNS ;)

This tutorial will show you how to configure ddclient on Raspbian and Ubuntu. Many tutorials don't explain what to do if your server is behind a router, but this one will. I recently set up a backup server on an internet connection that has a dynamic IP address. So far, I've been spoiled at home because my ISP (PlusNet) makes switching to a static IP address easy and cheap, so obviously I did that. This time though, I didn't have that option, and I didn't want to configure a dynamic dns client on that router either, so I had to set it up on the server itself.

Google recently announced that it is going to start prioritising websites that offer HTTPS by default in its search engine results. At first, the positive effect will be small to give webmasters time to switch to HTTPS, but it will gradually become more of a significant signal. This is a good thing for the internet: SSL doesn't cost much for webhosts, and it makes it more difficult to spy on everyone all the time! The Electronic Frontier Foundation praised the decision calling it a "bold and welcome move to protect users". I wanted to start offering some of the services I run on my server to other friends and family, and I couldn't easily install the CAcert root on all of their devices, so this seemed like a good time to purchase a cert. The following describes how I configured the various services (Apache, Postfix, Dovecot) to use the new certificate from COMODO.