Endlessh

What Endlessh is

Endlessh is a free, self-hosted SSH tarpit for Linux that slowly sends random banner text to keep unwanted SSH clients occupied. The project describes placing a real SSH server on another port, so clients that connect to the tarpit remain there instead. Endlessh is a standalone, single-threaded C program that uses poll() to handle multiple clients. Since it sends banners before cryptographic exchange, it does not rely on cryptographic libraries. Defaults include a 10000-millisecond delay between messages, a maximum banner line length of 32 characters, and a limit of 4096 clients; additional connections wait in a queue. It supports IPv4 and IPv6, with options to bind to either address family alone. Diagnostics are quiet by default, with repeatable verbosity flags for standard and debug logging and support for syslog. Its configuration syntax is similar to OpenSSH and defaults to /etc/endlessh/config. SIGTERM gracefully stops the daemon, SIGHUP reloads its configuration, and SIGUSR1 writes connection statistics to the log. The repository identifies the license as the Unlicense and provides GitHub Issues and Pull Requests for discussion.