.\" Copyright (c) 2020 Markus Hennecke <markus-hennecke@markus-hennecke.de>
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.Dd $Mdocdate: July 12 2020 $
.Dt SSH-SENTRYD 8
.Os
.Sh NAME
.Nm ssh-sentryd
.Nd daemon watching for failed authentications from
.Xr sshd 8
in
.Pa /var/log/authlog ,
adding IPs trying to login with invalid user names to the
.Xr pf 4
table
.Qq blacklist .
.Sh SYNOPSIS
.Nm
.Bk -words
.Op Fl dv
.Ek
.Sh DESCRIPTION
The
.Nm
daemon watches the
.Xr sshd 8
log entries in
.Pa /var/log/authlog
and adds IPs trying to login with invalid user names to the
.Xr pf 4
table
.Qa blacklist .
.Pp
The options are as follows:
.Bl -tag -width "-d"
.It Fl d
Do not daemonize.
If this option is specified,
.Nm
will run in the foreground and log to
.Em stderr .
.It Fl v
This option allows
.Nm
to send DEBUG priority messages to syslog.
.El
.Pp
.Nm
watches for new log lines in
.Pa /var/log/authlog
matching log entries starting with one of:
.Bl -tag -width "Failed password for invalid user from" -compact
.It Li Failed password for invalid user from
.It Li Failed password for root from
.El
.
The IP address following one of the above log lines is then added to the
.Xr pf 4
table
.Qq blacklist .
.Pp
If the log file
.Pa /var/log/authlog
is rotated it is reopened.
.Sh SEE ALSO
.Xr pf 4
.Xr sshd 8