.Dd $Mdocdate: January 29 2020 $
.Dt ENDLESSH 1
.Os
.Sh NAME
.Nm endless
.Nd An SSH tarpit
.Sh SYNOPSIS
.Nm endless
.Op Fl 46chsvV
.Op Fl d Ar delay
.Op Fl f Ar config
.Op Fl l Ar max banner length
.Op Fl m Ar max clients
.Op Fl p Ar port
.Sh DESCRIPTION
.Nm
is an SSH tarpit that very slowly
sends an endless, random SSH banner.
.Pp
.Nm
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 the script kiddies get stuck in this tarpit
instead of bothering a real server.
.Pp
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.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl 4
Forces
.Nm
to use IPv4 addresses only.
.It Fl 6
Forces
.Nm
to use IPv6 addresses only.
.It Fl d Ar delay
Message milliseconds delay. Default: 10000
.It Fl f Ar config
Set and load config file.
By default
.Nm
looks for /etc/endlessh/config.
.It Fl h
Print the help message and exit.
.It Fl l Ar max banner length
Maximum banner line length (3-255). Default: 32
.It Fl m Ar max clients
Maximum number of clients. Default: 4096
.It Fl p Ar port
Set the listening port. By default
.Nm
listens on port 2222.
.It Fl s
Print diagnostics to syslog. By default
.Nm
prints them to standard output.
.It Fl v
Print diagnostics. Can be specified up to twice to increase verbosity.
.It Fl V
Causes
.Nm
to print version information and exit.
.El
.Pp
If
.Nm
receives the SIGTERM signal it will gracefully shut
down the daemon, allowing it to write a complete, consistent log.
.Pp
A SIGHUP signal requests a reload of its configuration file.
.Pp
A SIGUSR1 signal will print connections stats to the log.
.Sh FILES
.Bl -tag -width /etc/endlessh/config -compact
.It Pa /etc/endlessh/config
The default
.Nm
configuration file.
.El