Enabling SSL in Apache

Recently I had to do this task twice in the last month at different localhosts, so I’m writing this post as a personal note (all this blog is meant to be a sort of memo book, though).

This mini-guide is heavily based on pradeepchhetri’s answer on stackexchange and this tutorial from 2012, so credit goes to them.

First, create the certificates:
cd /etc/apache2/
sudo openssl genrsa -out localhost.key 1024
sudo openssl req -new -key localhost.key -x509 -out localhost.crt
sudo chmod 600 localhost.*

Then edit /etc/apache2/sites-available/default-ssl and put the important parts:
<VirtualHost *:443>
SSLEngine on
SSLCertificateFile /etc/apache2/localhost.crt
SSLCertificateKeyFile /etc/apache2/localhost.key

Finally activate SSL and reload Apache:
sudo a2enmod ssl
sudo a2ensite default-ssl
sudo service apache2 reload

That’s it!

PS: These tips are for development pruposes. In production you’ll need a chained certificate (aka certificate bundle).


On link removal requests

I use to receive tons of spammy emails weekly. Thanks to email filters most of the spam stuff is automatically redirected to /dev/null. However, some time ago I received one that looked presumably legit–Note: I’ve anonymized it to preserve the identity of both parts.

Dear Webmaster,

It has come to our attention that your site contains backlinks to <awesome_company>. As part of an ongoing link clean-up and proactive link profile management program for the company, we have identified that these links that point to our URL are violating Google’s link quality guidelines and also our internal link guidelines.

Therefore could we please have these links removed at your earliest possible convenience. They are located at the following URL’s.


If you would like help on getting these removed please do not hesitate to contact us directly through this email. If no action is taken we will be adding your site into our Google disavow file which helps Google to better combat web spam and also effectively cuts the link between your site and ours.

Please advise us if you have been able to successfully remove the links. We really appreciate your effort and urgency on this issue.

Name – <awesome_company>

So this looked like legit to me at first. But then I realized that it was someone from that company who put that link on one page at my website. Moreover, a quick Internet search revealed a number of interesting write-ups:

In the end I did nothing. I don’t know what happened, but honestly I don’t care. Let the Internet take its natural, chaotic course.

How to give a scientific presentation

Recently I stumbled upon an excellent compendium of tips and advices for giving a scientific presentation. Since I can’t agree more on the vast majority of the contents covered there, I’m just sharing the link to the PDF document. Credit goes to by Kevin D. Lafferty.

The document also covers 3 types of presentation outlines: paper, essay, and plot. So even if you work outside academia you would benefit from paying attention to those advices.

Installing Windows 64bit in VirtualBox

Today I got stuck with a 0x000025 error while trying to install Windows 7 64bit in VirtualBox. It turns out that I/O APIC must be enabled, according to the documentation:

On any host, you should enable the I/O APIC for virtual machines that you intend to use in 64-bit mode. This is especially true for 64-bit Windows VMs.

So, that’s all folks. Go to Settings > System > Extended features and check Enable IO APIC.