Part of an intentionally trivial set of tools that I find myself using over and over, this little server just listens on port 40k and bounces UDP back.
Lately, I've been thinking a lot about the way I use tools and compose tools, and I realized that I wanted a lot of these extremely simple utilities instantly on tap. The 5 minutes it was taking me to make a new one or look up a quirk had added up. So this is part of a collection of tools that I'm slowly building up which do exactly, completely, and only what you expect.