Are you already hosting your own mail- or webserver and do you enjoy the flexibility, control and freedom self-hosting gives you? Besides the many advantages like better privacy and the power to customize it gives you personally, you can also offer your services to other people. Even tough there are a large number of budget hosting companies, many customers are willing to pay for better support or the comfort to have you around for questions. Continue reading →
Despite some notions that SSDs or HFS drives don't need defragmenting, I have often read and experienced myself that defragmenting your Mac every few years will clearly make it faster.
I had some trouble running iDefrag and would like to share a little trick I learnt. Basically it will refuse to run a full defrag, while your system drive is mounted. Restarting didn't help. Here is what I did in the end: Continue reading →
I noticed an increasing number of phising emails from 'Telekom' and 'DHL' making it into user mailboxes. ClamAV anti-virus together with Sane Security Phising checks does a good job in stopping zero-day phising emails.
On a different account, DKIM Email signing seems to be preferred by Google these days. So time to add that too.
Many times I get upset with websites, who display accounting data in a table, but don't offer a way to download it. This includes banks, payment processors, etc. Even if they offer it, there is a chance it's the wrong format for your purpose. Continue reading →
After years of preparation, we are proud to present a usable product of a stochastic optimization library. The core Java libraries were programmed by Nils Löhndorf. I contributed the iPython interface and other 'glue'. We are excited to find out which uses people will find for this technology.
Forecasts are rather difficult, especially when they're about the future. Or so the saying goes. While predictiong returns is a pointless exercise, there is some value in keeping an eye on correlations. Continue reading →
I use SSH for pretty much anything from VPN, server administration, database connections or iPython work on remote machines. When working from weird places and with weird internet connections SSH become painfully slow. I already use Mosh, but that also relies on ordinary SSH to initiate the connection.
Last week we discussed Linux Debian's apt-get update mechanism and how to fully automate essential updates. This week I'd like to demonstrate how to do the same thing for Python. I admit that keeping Python packages up-to-date is probably not half as essential as keeping internet-facing server infrastructure updated. Nonetheless I like to work with the latest versions of packages, as they might fix problems or add features. Continue reading →
This week's massive SSL-security vulnerability showed how important regular security updates for all of our software is. Because – let's face it – today's world is largely powered by software. Software that is written by humans, who make mistakes when writing it. The rule should be: retire it or update it. Continue reading →
I'm back in Shanghai and faced with the pollution problem once again. Here a quick update on the last months. You can clearly see a reduction in pollution around Chinese New Year, when factories are shutting down. With warmer weather the readings also seem to be lower. I don't know the reason, but anecdotal evidence gives the same effect for Beijing. An expert from Vienna University of Economics is currently analyzing the data and correlating it with weather observations. I'll give an update, when some results emerge.
This morning I came across this post by Kelly Norton. He calculated the number of 'pleasant' days for each US zip-code area. California seems to win the race with more than 180 'pleasant' days each year. A pleasant day is defined by the min- and max temperature not exceeding certain limits. Continue reading →
A.. for AngularJS. Drives the user frontend.
S.. for Supervisord. Takes care of processes.
P.. for Python. Quick way to implement almost any business logic.
E.. for Nginx. Fast web server for static files and to add SSL.
L.. for Linux.
Today I stumpled over a rather fascinating post on Sinosplice. It basically says that all maps in China are based on a different coordinate system than Western maps. As a result, 'Western' GPS-coordinates projected onto them will be off between 300 to 500m.
I noticed this issue while playing Ingress in Shanghai. While walking along the Bund, I always ended up in the Pu-river. It seems that Google Maps has a correction-algorithm built in, while Ingress hasn't. This still doesn't help you while tagging photos or sharing your position with friends. Continue reading →
Update Aug 9, 2013: The biggest German email providers are currently running a big marketing campaign and promise secure email. They are using the same technique described on this page. After checking my logs, I can confirm that GMX-emails were delivered unencrypted on Aug 5, but arrived encrypted on Aug 6.
Thanks to Mr. Snowden, we know two important facts about the world of security and email:
First, most governments in the world will eavesdrop and store your communication, if they get the chance. They don't have a specific reason and the benefits are highly disputed.
Second, your users can't/won't use PGP or S/MIME to encrypt their email.
The job is left to admins. We need to maximize usability and compatibility, while ensuring that user data stays confidential. If you are running Postfix, I'd like to draw your attention to some useful settings that will protect your user's email in transit. If emails stay on the same server or the other server is secured as well, there is little chance to intercept messages on a big scale. If your users are sending emails to Gmail or Hotmail, then interception is still possible at the receiving end.