sane-project-backends/doc/saned.man

.TH saned 1 "07 Apr 2002"
.IX saned
.SH NAME
saned - SANE network daemon
.SH SYNOPSIS
.B saned
.RB [ -d | -s
.RI [ n ]]
.SH DESCRIPTION
.B saned
is the SANE (Scanner Access Now Easy) daemon that allows remote clients
to access image acquisition devices available on the local host.
.SH OPTIONS
.PP
The
.B -d
and
.B -s
flags request that
.B saned
run in debug mode (as opposed to
.BR inetd (8)
mode).  In this mode,
.B saned
explicitly waits for a connection request.  When compiled with
debugging enabled, these flags may be followed by a number to request
debug info. The larger the number, the more verbose the debug output.
E.g., -d128 will request printing of all debug info. Debug level 0 means
no debug output at all. The default value is 2. If flag
.B -d
is used, the debug messages will be printed to stderr while
.B -s
requests using syslog. 
.SH CONFIGURATION
First and foremost: please do
.I not
install
.B saned
as setuid root without due consideration.  Especially when using
dynamic linking, there is a potential for introducing security holes
when running this program as root.
.PP
The contents of the
.I saned.conf
file is a list of host names or IP addresses that are permitted to
use local SANE devices.  Connections from localhost are always permitted.
Empty lines and lines starting with a hash mark (#) are ignored.  A line
containing the single character ``+'' is interpreted to match any hostname.
This allows any remote machine to use your scanner and may present a security
risk, so this shouldn't be used unless you know what you're doing.  A sample
configuration file is shown below:
.PP
.RS
scan-client.somedomain.firm
.br
# this is a comment
.br
192.168.0.1
.RE
.PP
The case of the host names does not matter, so AHost.COM is considered
identical to ahost.com.

For
.B saned
to work properly, it is also necessary to add a configuration line to
.IR /etc/inetd.conf .
The configuration line normally looks like this:
.PP
.RS
sane stream tcp nowait saned.saned @SBINDIR@/saned saned
.RE
.PP
However, if your system uses
.BR tcpd (8)
for additional security screening, you may want to disable saned
access control by putting ``+'' in
.IR saned.conf
and use a line of the following form in
.IR /etc/inetd.conf
instead:
.PP
.RS
sane stream tcp nowait saned.saned /usr/sbin/tcpd saned
.RE
.PP
Note that both examples assume that there is a
.B saned
group and a
.B saned
user.  If you follow this example, please make sure that the 
access permissions on the special device are set such that
.B saned
can access the scanner (the program generally needs read and
write access to scanner devices).
.PP
If xinetd is installed on your system instead of inetd the following example
for xinetd.conf may be helpful:
.PP
.RS
# default: off
.br
# description: The sane server accepts requests 
.br
# for network access to a local scanner via the
.br
# network.
.br
service sane
.br
{
.br
   port        = 6566
.br
   socket_type = stream
.br
   wait        = no
.br
   user        = saned
.br
   group       = saned
.br
   server      = @SBINDIR@/saned
.br
}
.RE
.PP
Finally, it is also necessary to add a line of the following form to
.IR /etc/services :
.PP
.RS
sane 6566/tcp # SANE network scanner daemon
.RE
.PP
Note that port number 6566 has not been officially assigned to the
SANE network protocol and may thus change in the future.
.PP

.SH "RESTRICTIONS"
In addition to the control connection (port 6566) saned also uses a data
connection. The port of this socket is selected by the operating system and
can't be specified by the user currently. This may be a problem if the
connection must go through a firewall (packet filter).

.SH FILES
.TP
.I /etc/hosts.equiv
The hosts listed in this file are permitted to access all local SANE
devices.  Caveat: this file imposes serious security risks and its use
is not recommended.
.TP
.I @CONFIGDIR@/saned.conf
Contains a list of hosts permitted to access local SANE devices (see
also description of
.B SANE_CONFIG_DIR
below).
.TP
.I @CONFIGDIR@/saned.users
If this file contains lines of the form
.PP
.RS
user:password:backend
.PP
access to the listed backends is restricted. A backend may be listed multiple
times for different user/password combinations. The server uses MD5 encryption
if supported by the client.
.SH ENVIRONMENT
.TP
.B SANE_CONFIG_DIR
This environment variable specifies the list of directories that may
contain the configuration file.  Under UNIX, the directories are
separated by a colon (`:'), under OS/2, they are separated by a
semi-colon (`;').  If this variable is not set, the configuration file
is searched in two default directories: first, the current working
directory (".") and then in @CONFIGDIR@.  If the value of the
environment variable ends with the directory separator character, then
the default directories are searched after the explicitly specified
directories.  For example, setting
.B SANE_CONFIG_DIR
to "/tmp/config:" would result in directories "tmp/config", ".", and
"@CONFIGDIR@" being searched (in this order).

.SH "SEE ALSO"
sane(7), scanimage(1), xscanimage(1), xcam(1), sane\-dll(5), sane\-net(5),
sane\-"backendname"(5)

.I http://home.nexgo.de/jochen.eisinger/saned/
.SH AUTHOR
David Mosberger