Dr. Lawlor's Code, Robots, & Things

August 20, 2014

Setting up a HTTPS server via Apache mod_ssl: start to finish

Filed under: Linux, Servers, Sysadmin — Dr. Lawlor @ 1:42 am

If you’re like me, you’re already running a Linux web server.  It uses port 80 by default, which sends everything unencrypted across the network.  This is a bad idea, because anybody watching your users’ network traffic can see everything sent in either direction.  So you want to use HTTPS, which runs over TCP port 443.  Here’s how to set it up!


August 18, 2014

UAF Eduroam setup in Linux

Filed under: Linux — Dr. Lawlor @ 5:23 pm

Eduroam provides simple, no-login roaming wifi at a bunch of higher educational institutions.  It’s an IEEE 802.1X authentication setup, where you set up credentials at your home institution, and they can be used worldwide.

First go to https://nah.alaska.edu/eduroam/, and log in with your UA credentials (same as blackboard, UAOnline, etc).  Download the Root certificate (rootCA.crt) and your “PKCS12 with intermediate and root” .p12 file, and save them to a fixed location on your machine.

Select the “eduroam” network from Network-Manager applet.
Should auto-identify as WPA/WPA2 Enterprise.
Authentication is TLS.  (It’s NOT Tunneled TLS or PEAP here, like it is most other places.)
Identity is “YOURLOGIN@alaska.edu”.
User certificate is left blank (for some reason).
CA certificate is rootCA.crt file downloaded above.
Private key is your .p12 file, again from above.
Private key password is YOURLOGIN.
Overall, it should look like this browser and network manager setup.

This shows Eduroam working correctly in Linux.

This shows Eduroam working correctly in Linux.

Now connect to the eduroam wifi!

It should connect within 10 seconds; if it lags for half a minute or more something’s messed up.  You need to download new certificates every year, so keep this post handy!

August 9, 2014

WebGL Nonlinear Iterated Function System Rendering

Filed under: Random Thoughts — Dr. Lawlor @ 1:13 am

A few years ago I built a fun little nonlinear iterated function system fractal renderer that works on the GPU.  I got very pretty pictures and interesting scientific results, but my demo is an OpenGL application, so it’s a pain for people to download and see. Juergen Wothke just ported my renderer to use WebGL, so it can animate beautiful swoopy lines in realtime, at least in Chrome. A prerecorded video doesn’t capture the full resolution or the 60fps speed that a good graphics card is capable of producing!

Read his technical details at his blog.  Browser audio processing was the main headache.

I’d love to see somebody build a full-on interactive editor for nonlinear IFS using WebGL and my GPU rendering technique!

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