Following my previous post, I now have a working config with PostgreSQL.

The aim of this is to have a postfix installation capable mainly of “aliasing” e-mails. Let’s say I have a domain “example.com” and I want to manage e-mail addresses for that domain. But, it’s a small domain with only a handful of users and I don’t want to store mails locally, just alias them to the users private e-mails addresses.

While the aim is only to alias e-maile, the config explained below is still capable of delivering mail locally (storing them directly to disk), but as there is no set-up to access those mails (POP/IMAP/webmail), it’s only marginally useful. But it gives you a working framework if you want to add these features yourself. Read the rest of this entry »

There are many postfix tutorials out there. I’ve always wondered what the hell I was copy/pasting onto my system and decided to start (nearly) from scratch. I took one of those tutorials (don’t remember which one) as inspiration, but based the final result on the official docs. I kept what I liked, changed some settings I did not like so much, and threw out a few other things which I deemed useless.

The main problem with those tutorials is that they show you a final result without telling you how they ended up with the result, sometimes it looks like an amalgam of other tutorials ending up in a huge “frankenconfig”. I don’t like deploying something where I don’t know what it’s doing…

The final result is a config which is stripped down to my most basic needs.

The first iteration will be an extremely simple config:

• No database will be used to store mail config. This however is something I will certainly implement.
• Only simple spam handling using blocklists.
• No antivirus.
• No webmail access.
• No POP access.
• No IMAP access.
• Not relay mails for other hosts (only local delivery)j.

For now, I only require e-mail aliasing. That is, I only want to handle e-mails destined for my domains, but I only want to “forward” them to other destinations. Local delivery (and access to those mails) may or may not be implemented later. It will be set up on an Ubuntu Precise Pangolin Server and should get you started for a basic mail server.

Here’s the main config:

The most interesting part of the config is at the end of the config after the “Virtual Mail” header. This part defines which e-mail addresses the MTA is handling and how. Will the mails be stored locally? Will they be “aliased” to another e-mail?

The config should be documented well-enough.

Examples for the hash files (for an explanation what they do, see above):

I actually did not believe it’s this simple.

Creating the tunnel is as easy as typing:

Which can be improved with

See the man page on the details of the extra options.

This will open up port 1080 on your local machine, providing a SOCKS proxy (SOCKS5 if I’m right). You can then specify this in any application supporting SOCKS proxies. This includes Firefox and Chrome. With Firefox it’s straight-forward. You can find it in the usual proxy page in the settings.

For chrome it’s a bit more tricky. While you can specify a SOCKS proxy, it seems to ignore it. If you want to enable your tunnel, you have to run chrome with the following command-line flag:

(or use chrome. Whatever rocks your boat).

Once this is set up, what will happen is that your application/browser will send all requests to your locally running SSH instance. This in turn will forward it to the remote host, where the request will be sent out on the web. The response takes the inverse direction. As stated by linode, this is great if you’re on an untrustworthy network!

Sources:

• http://www.linode.com/wiki/index.php/SSH_Dynamic_Port_Forwarding
• man ssh

Are you using git/svn/mercurial/bazaar as version control system and you ever wanted to visualize your work, how the project developed over time well Gource is there to visualize all this in a beautiful way. It takes the history of your svn/git/mercurial/bazaar repository and visualizes the changes over time, by whom they were done and so forth.

Now run the following with path/to/project being your projects root directory, and give gource the .git subfolder. Run it and you should see the animation being presented.

Now to export this to an mpeg4 video do the following.

Here an example I created from one of my projects.

I am currently writing a new munin plugin to monitor memory usage on Solaris machines. Strangely the existing plugins are fairly useless. Currently the script is running on a test-machine. If the results are satisfactory, I’ll post them here. Stay tuned.

Here’s a small bash function to provide TAB-completion for fabric tasks.

Simply add the following to your ~/.bashrc

You may already have a block like if [ -f /etc/bash_completion ]... in that case, simply add the extra line into that block.

Have fun

I’ve been down that road many times: “What folder takes up the most disk space”. Over the time lots of junk accumulates on one’s disk. So far the following one-liner has been a trusty companion:

Some other tools are available of which I don’t remember the names. But why not use something that integrates well with Konqueror in KDE? Like “FSView” (short for file-size view)? Well, for one thing it’s painfully slow, and what makes things worse it’s utterly unreadble. But what I figured out this afternoon, is that the app actually offers some quite nice settings. The buty of Konqueror integration is that the “plugins” can insert thei own menu-items wherever they like. Which is nice, because they then integrate well with already existing menu options. But on the other hand, if you are used to open menu paths like “Plugins -> MyPlugin -> Settings” or “Edit/Tools -> Options -> Plugins” you won’t find them.

In the case of fs-view, the options are neatly tucked away in the “View” menu. Which actually makes perfect sense. But working too much on Windows-inspired user interfaces twisted my mind too much and I go looking into the non-obvious places out of pure habit 😉

Now, to spice up fsview a bit I made the following changes:

• In the “Visualisation” sub-menu:
  • Set “Nesting” to “Vertical”
  • Set “Border” Width to 3
  • Disabled both options “Enable Rotation” and “Shading”
• In the “Stop at Area” sub-menu:
  • Set value to “400”
• In the “Stop at Depth” sub-menu:
  • Set value to “2”

Both “Stop at …” settings limit the number of times fs-view has to redraw/rearrange the grid. This should speed things up and it becomes more readable. The end result looks something like this:

FSView with customizations

In any case, running fs-view on folders with a large number of files can be very slow and make konqueror even unresponsive while it’s running. Be patient. In my opinion, if you want to determine the biggest file/folder as quickly as possible, the “du -s” method (as outlined above) is preferrable.

I never cared about which terminal to chose. I usually ended up with aterm on non-KDE boxes and Konsole on KDE boxes. This comparison (and the attached comments) is actually quite interesting.

The results were quite surprising 😉