Comment by daveslash

In my RnD testing, when I just need an arbitrary port, 666 is my go to.

(a) It's almost never used by anything else and (b) <3 Doom

Unfortunately, I showed some software in a sprint demo once, using 666 as an arbitrary port. I was very clear that this port can be anything, because the software was made to be configurable by the user, and of course the project manager wrote it down and put it in the "official" and released documentation that the customer must use port 666. facepalm.