.TH SMTPD 8 "August 2007" "OpenFWTK"
.SH NAME
smtpd \- SMTP proxy (client portion)
.SH SYNOPSIS
.BI "smtpd [-daemon " "port" "] [-fastdaemon " "port" "] [-as " "tag" "]"
.SH DESCRIPTION
.IX  "smtpd"  ""  "\(em SMTP proxy (client portion)"
The Firewall Toolkit
.B smtpd
proxy is an application level proxy that provides configurable
access control and logging  mechanisms. The
.B smtpd
client proxy together with the
.B smtpfwdd
server proxy, which run on the firewall, transfer mail between
internal and external mail servers, using rules you supply.
.PP
All packets, and therefore all application requests go to the
firewall.  On the firewall, the
.B smtpd
and
.B smtpfwdd
proxy software relay information from one side of the firewall to
the other.  They prevent versions of
.I sendmail
on the external network from talking with versions of
.I sendmail
on the internal network, and vice versa. No IP packets pass from
one side of the firewall to the other.  All data is passed at the
application level.
. PP
The client portion of the SMTP proxy
.RB "(" smtpd ")"
generally runs as a daemon (invoked from
.IR "/etc/rc.local" )
and listens for requests on the standard SMTP port (25, as indicated
in
.IR "/etc/services" ).
Whenever the system receives an SMTP request on this port, the
.B smtpd
client collects the mail from the sender, logs the message, and
places the mail in a temporary directory.  Periodically, based on
a configurable value (by default every 60 seconds), the server
daemon
.RB "(" smtpfwdd ")"
wakes up and checks to see if there is any new mail.  The
.B smtpfwdd
daemon checks the headers of the mail for formatting problems.  It
then calls the configured message transfer agent (usually
.B ssmtp
) for final delivery.
.SH OPTIONS
.SS Command Line Options
The
.B smtpd
proxy recognizes the following command line options (whether started
from the command line or from within
.IR /etc/rc.local ):
.TP
.BI "-daemon " port
Indicates that the
.B smtpd
proxy runs as a daemon, and the port (name or number) on which the
.B smtpd
proxy listens. When
.IR "-daemon"
option is used, configuration is being read from
.IR netperm-table
for every new connection accepted by proxy.
.IP
.I port
Specifies either a numeric id or symbolic name from the
.I /etc/services
file.
.TP
.BI "-fastdaemon " port
Indicates that the smtpd proxy runs as a daemon, and the port (name
or number) on which the smtpd proxy listens. When
.IR "-fastdaemon"
option is used, configuration is being read from
.IR netperm-table
once the daemon starts or if
.IR SIGHUP
is received.
.TP
.BI "-as " tag
Changes default application tag for
.IR netperm-table
from "smtpd" to any given
string.
.SS Configuration Options
The
.B smtpd
proxy reads configuration rules from the
.IR "/usr/local/etc/netperm-table" .
It reads all rules using the
.B smtpd
,
.B smap
and
.B *
(wildcard) keywords. The
.B smtpd
proxy reads the
.I netperm-table
from top to bottom.  If there are multiple rules in the table that
could apply for a particular attribute, the
.B smtpd
proxy uses the first one that it finds.  See
.BR "netperm-table"  (5)
for a more complete explanation of 
.I netperm-table
syntax and precedence.
.B smap
configuration options are included for TIS fwtk compatibility.
.PP
The
.B smtpd
proxy recognizes the following attributes:
.TP
.BI "directory " directory
Specifies the directory that the
.B smtpd
proxy makes its root directory before providing service.  This is
also the directory where the
.B smtpd
proxy stores incoming messages.
.TP
.BI "hosts " "host-pattern [host-pattern...] [options]"
rules specify host and access permissions. Typically, a
hosts rule will be in the form of:
.na
.sp 1
smtpd: deny-hosts unknown
.sp
smtpd: hosts 192.33.112.* 192.94.214.* 
.ad
.sp 1
There may be several host patterns following the "hosts"
keyword, ending with the first optional parameter beginning
with '-'. Optional parameters permit the selective enabling
or disabling of logging information, etc. Sub-options are:
.IP
.IP
.B \-log
Increases log verbosity
.IP
.BI "[-client]-dscp " dscp-tag-name
.br
.BI "[-client]-dscp " dscp-hex-value
specifies diffserv codepoint (QoS/ToS mark) for client to proxy connection.
.TP
.BI "groupid " group
Specifies the name of the group the
.B smtpd
proxy uses when running.
.RS
.TP
.I group
Specifies either a name or numeric id from the
.I /etc/group
file.
.RE
.TP
.BI "maxbytes " number
Specifies max email size.
.TP
.BI "maxheaderline " number
Specifes max single header line length. 998 is default as recommended by
rfc2822.
.TP
.BI "maxrecip " number
Specifies maximal number of receipients per SMTP session.
.TP
.BI "timeout " seconds
Specifies the number of seconds the
.B smtpd
proxy is idle (with no network activity) before disconnecting
.TP
.BI "userid " user
Specifies the user ID the proxy uses when running.
.RS
.TP
.I user
Specifies either a name or numeric id from the
.I /etc/passwd
file.
.RE
.SH EXAMPLES
This example indicates that the
.B smtpd
and
.B smtpfwdd 
proxies use the directory
.I /var/spool/smtpd
as their root directories:
.sp 1
.nf
.na
.RS
smtpd:	permit-hosts 10.0.0.* outerrelay.illuminati.int	
smtpd, smtpfwdd:    directory       /var/spool/smtpd
.RE
.fa
.fi
.SH FILES
.IP /etc/rc.local
Command script that controls automatic reboot, and includes startup
information for the
.B smtpd
proxy.
.IP /usr/local/etc/netperm-table
The network permissions file contains configuration information
for the Firewall Toolkit, including the
.B smtpd
proxy.
.IP /var/spool/smtpd
The directory that the
.B smtpd
proxy uses as its root directory.
.SH BUGS
There is no advanced relay control. We accept everything from allowed hosts
so relays should be properly configured to prevent unauthorized relaying.
.PP
smtpd does not do ESMTP. You may consider that as feature as well.
.PP
Report bugs to  arkenoi@gmail.com or fwtk-users@buoy.com mailing list.  
Include a complete
example, explaining what you expected to happen and what actually
happened.  Be sure to indicate the type of system (operating system,
hardware, etc.) you are using, as well as the version of the smtpd
proxy.
.SH AUTHOR
Obtuse Systems Corporation.
.SH SEE ALSO
.BR netperm-table "(5), " rc "(8), " smtpd "(8)"