Fritz Box DNS is Awesome

I’m pretty amazed by my Fritz Box right now. I knew already that I can access my router by typing in the browser address line, but it gets even better. After installing spark on my machine and firing up the pyspark console, I noticed a particular log line:

INFO SparkUI: Started SparkUI at

I really don’t get how spark does this reverse DNS lookup, but it actually works. The URL is valid and points to my spark UI. And all other machines on the network are also reachable, even the windows ones.