Endlessh is an SSH tarpit that very slowly sends an endless, random SSH banner.
 It keeps SSH clients locked up for hours or even days at a time. The purpose is
 to put your real SSH server on another port and then let abusive bots get stuck
 in this tarpit instead of bothering a real server.
 .
 Since the tarpit is in the banner before any cryptographic exchange occurs,
 this program doesn't depend on any cryptographic libraries. It's a simple,
 single-threaded, standalone C program. It uses poll() to trap multiple clients
 at a time.
 .
 See https://nullprogram.com/blog/2019/03/22/ for more details.