path: root/rsyncd.conf.5

.TH "rsyncd.conf" "5" "21 Dec 2015" "" ""
.SH "NAME"
rsyncd.conf \- configuration file for rsync in daemon mode
.SH "SYNOPSIS"

.PP 
rsyncd.conf
.PP 
.SH "DESCRIPTION"

.PP 
The rsyncd.conf file is the runtime configuration file for rsync when
run as an rsync daemon.
.PP 
The rsyncd.conf file controls authentication, access, logging and
available modules.
.PP 
.SH "FILE FORMAT"

.PP 
The file consists of modules and parameters. A module begins with the
name of the module in square brackets and continues until the next
module begins. Modules contain parameters of the form \(dq\&name = value\(dq\&.
.PP 
The file is line\-based \-\- that is, each newline\-terminated line represents
either a comment, a module name or a parameter.
.PP 
Only the first equals sign in a parameter is significant. Whitespace before
or after the first equals sign is discarded. Leading, trailing and internal
whitespace in module and parameter names is irrelevant. Leading and
trailing whitespace in a parameter value is discarded. Internal whitespace
within a parameter value is retained verbatim.
.PP 
Any line \fBbeginning\fP with a hash (#) is ignored, as are lines containing
only whitespace. (If a hash occurs after anything other than leading
whitespace, it is considered a part of the line\(cq\&s content.)
.PP 
Any line ending in a \e is \(dq\&continued\(dq\& on the next line in the
customary UNIX fashion.
.PP 
The values following the equals sign in parameters are all either a string
(no quotes needed) or a boolean, which may be given as yes/no, 0/1 or
true/false. Case is not significant in boolean values, but is preserved
in string values.
.PP 
.SH "LAUNCHING THE RSYNC DAEMON"

.PP 
The rsync daemon is launched by specifying the \fB\-\-daemon\fP option to
rsync.
.PP 
The daemon must run with root privileges if you wish to use chroot, to
bind to a port numbered under 1024 (as is the default 873), or to set
file ownership.  Otherwise, it must just have permission to read and
write the appropriate data, log, and lock files.
.PP 
You can launch it either via inetd, as a stand\-alone daemon, or from
an rsync client via a remote shell.  If run as a stand\-alone daemon then
just run the command \(dq\&\fBrsync \-\-daemon\fP\(dq\& from a suitable startup script.
.PP 
When run via inetd you should add a line like this to /etc/services:
.PP 
.nf 
  rsync           873/tcp
.fi 

.PP 
and a single line something like this to /etc/inetd.conf:
.PP 
.nf 
  rsync   stream  tcp     nowait  root   /usr/bin/rsync rsyncd \-\-daemon
.fi 

.PP 
Replace \(dq\&/usr/bin/rsync\(dq\& with the path to where you have rsync installed on
your system.  You will then need to send inetd a HUP signal to tell it to
reread its config file.
.PP 
Note that you should \fBnot\fP send the rsync daemon a HUP signal to force
it to reread the \f(CWrsyncd.conf\fP file. The file is re\-read on each client
connection.
.PP 
.SH "GLOBAL PARAMETERS"

.PP 
The first parameters in the file (before a [module] header) are the
global parameters.
Rsync also allows for the use of a \(dq\&[global]\(dq\& module name to indicate the
start of one or more global\-parameter sections (the name must be lower case).
.PP 
You may also include any module parameters in the global part of the
config file in which case the supplied value will override the
default for that parameter.
.PP 
You may use references to environment variables in the values of parameters.
String parameters will have %VAR% references expanded as late as possible (when
the string is used in the program), allowing for the use of variables that
rsync sets at connection time, such as RSYNC_USER_NAME.  Non\-string parameters
(such as true/false settings) are expanded when read from the config file.  If
a variable does not exist in the environment, or if a sequence of characters is
not a valid reference (such as an un\-paired percent sign), the raw characters
are passed through unchanged.  This helps with backward compatibility and
safety (e.g. expanding a non\-existent %VAR% to an empty string in a path could
result in a very unsafe path).  The safest way to insert a literal % into a
value is to use %%.
.PP 
.IP "\fBmotd file\fP"
This parameter allows you to specify a
\(dq\&message of the day\(dq\& to display to clients on each connect. This
usually contains site information and any legal notices. The default
is no motd file.
This can be overridden by the \fB\-\-dparam=motdfile=FILE\fP
command\-line option when starting the daemon.
.IP 
.IP "\fBpid file\fP"
This parameter tells the rsync daemon to write
its process ID to that file.  If the file already exists, the rsync
daemon will abort rather than overwrite the file.
This can be overridden by the \fB\-\-dparam=pidfile=FILE\fP
command\-line option when starting the daemon.
.IP 
.IP "\fBport\fP"
You can override the default port the daemon will listen on
by specifying this value (defaults to 873).  This is ignored if the daemon
is being run by inetd, and is superseded by the \fB\-\-port\fP command\-line option.
.IP 
.IP "\fBaddress\fP"
You can override the default IP address the daemon
will listen on by specifying this value.  This is ignored if the daemon is
being run by inetd, and is superseded by the \fB\-\-address\fP command\-line option.
.IP 
.IP "\fBsocket options\fP"
This parameter can provide endless fun for people
who like to tune their systems to the utmost degree. You can set all
sorts of socket options which may make transfers faster (or
slower!). Read the man page for the 
\f(CWsetsockopt()\fP
system call for
details on some of the options you may be able to set. By default no
special socket options are set.  These settings can also be specified
via the \fB\-\-sockopts\fP command\-line option.
.IP 
.IP "\fBlisten backlog\fP"
You can override the default backlog value when the
daemon listens for connections.  It defaults to 5.
.IP 
.SH "MODULE PARAMETERS"

.PP 
After the global parameters you should define a number of modules, each
module exports a directory tree as a symbolic name. Modules are
exported by specifying a module name in square brackets [module]
followed by the parameters for that module.
The module name cannot contain a slash or a closing square bracket.  If the
name contains whitespace, each internal sequence of whitespace will be
changed into a single space, while leading or trailing whitespace will be
discarded.
Also, the name cannot be \(dq\&global\(dq\& as that exact name indicates that
global parameters follow (see above).
.PP 
As with GLOBAL PARAMETERS, you may use references to environment variables in
the values of parameters.  See the GLOBAL PARAMETERS section for more details.
.PP 
.IP "\fBcomment\fP"
This parameter specifies a description string
that is displayed next to the module name when clients obtain a list
of available modules. The default is no comment.
.IP 
.IP "\fBpath\fP"
This parameter specifies the directory in the daemon\(cq\&s
filesystem to make available in this module.  You must specify this parameter
for each module in \f(CWrsyncd.conf\fP.
.IP 
You may base the path\(cq\&s value off of an environment variable by surrounding
the variable name with percent signs.  You can even reference a variable
that is set by rsync when the user connects.
For example, this would use the authorizing user\(cq\&s name in the path:
.IP 
.nf 
    path = /home/%RSYNC_USER_NAME% 
.fi 

.IP 
It is fine if the path includes internal spaces \-\- they will be retained
verbatim (which means that you shouldn\(cq\&t try to escape them).  If your final
directory has a trailing space (and this is somehow not something you wish to
fix), append a trailing slash to the path to avoid losing the trailing
whitespace.
.IP 
.IP "\fBuse chroot\fP"
If \(dq\&use chroot\(dq\& is true, the rsync daemon will chroot
to the \(dq\&path\(dq\& before starting the file transfer with the client.  This has
the advantage of extra protection against possible implementation security
holes, but it has the disadvantages of requiring super\-user privileges,
of not being able to follow symbolic links that are either absolute or outside
of the new root path, and of complicating the preservation of users and groups
by name (see below).
.IP 
As an additional safety feature, you can specify a dot\-dir in the module\(cq\&s
\(dq\&path\(dq\& to indicate the point where the chroot should occur.  This allows rsync
to run in a chroot with a non\-\(dq\&/\(dq\& path for the top of the transfer hierarchy.
Doing this guards against unintended library loading (since those absolute
paths will not be inside the transfer hierarchy unless you have used an unwise
pathname), and lets you setup libraries for the chroot that are outside of the
transfer.  For example, specifying \(dq\&/var/rsync/./module1\(dq\& will chroot to the
\(dq\&/var/rsync\(dq\& directory and set the inside\-chroot path to \(dq\&/module1\(dq\&.  If you
had omitted the dot\-dir, the chroot would have used the whole path, and the
inside\-chroot path would have been \(dq\&/\(dq\&.
.IP 
When \(dq\&use chroot\(dq\& is false or the inside\-chroot path is not \(dq\&/\(dq\&, rsync will:
(1) munge symlinks by
default for security reasons (see \(dq\&munge symlinks\(dq\& for a way to turn this
off, but only if you trust your users), (2) substitute leading slashes in
absolute paths with the module\(cq\&s path (so that options such as
\fB\-\-backup\-dir\fP, \fB\-\-compare\-dest\fP, etc. interpret an absolute path as
rooted in the module\(cq\&s \(dq\&path\(dq\& dir), and (3) trim \(dq\&..\(dq\& path elements from
args if rsync believes they would escape the module hierarchy.
The default for \(dq\&use chroot\(dq\& is true, and is the safer choice (especially
if the module is not read\-only).
.IP 
When this parameter is enabled, the \(dq\&numeric\-ids\(dq\& option will also default to
being enabled (disabling name lookups).  See below for what a chroot needs in
order for name lookups to succeed.
.IP 
If you copy library resources into the module\(cq\&s chroot area, you
should protect them through your OS\(cq\&s normal user/group or ACL settings (to
prevent the rsync module\(cq\&s user from being able to change them), and then
hide them from the user\(cq\&s view via \(dq\&exclude\(dq\& (see how in the discussion of
that parameter).  At that point it will be safe to enable the mapping of users
and groups by name using this \(dq\&numeric ids\(dq\& daemon parameter.
.IP 
Note also that you are free to setup custom user/group information in the
chroot area that is different from your normal system.  For example, you
could abbreviate the list of users and groups.
.IP 
.IP "\fBnumeric ids\fP"
Enabling this parameter disables the mapping
of users and groups by name for the current daemon module.  This prevents
the daemon from trying to load any user/group\-related files or libraries.
This enabling makes the transfer behave as if the client had passed
the \fB\-\-numeric\-ids\fP command\-line option.  By default, this parameter is
enabled for chroot modules and disabled for non\-chroot modules.
Also keep in mind that uid/gid preservation requires the module to be
running as root (see \(dq\&uid\(dq\&) or for \(dq\&fake super\(dq\& to be configured.
.IP 
A chroot\-enabled module should not have this parameter enabled unless you\(cq\&ve
taken steps to ensure that the module has the necessary resources it needs
to translate names, and that it is not possible for a user to change those
resources.  That includes being the code being able to call functions like
\f(CWgetpwuid()\fP
, 
\f(CWgetgrgid()\fP
, 
\f(CWgetpwname()\fP
, and 
\f(CWgetgrnam()\fP
).
You should test what libraries and config files are required for your OS
and get those setup before starting to test name mapping in rsync.
.IP 
.IP "\fBmunge symlinks\fP"
This parameter tells rsync to modify
all symlinks in the same way as the (non\-daemon\-affecting)
\fB\-\-munge\-links\fP command\-line option (using a method described below).
This should help protect your files from user trickery when
your daemon module is writable.  The default is disabled when \(dq\&use chroot\(dq\&
is on and the inside\-chroot path is \(dq\&/\(dq\&, otherwise it is enabled.
.IP 
If you disable this parameter on a daemon that is not read\-only, there
are tricks that a user can play with uploaded symlinks to access
daemon\-excluded items (if your module has any), and, if \(dq\&use chroot\(dq\&
is off, rsync can even be tricked into showing or changing data that
is outside the module\(cq\&s path (as access\-permissions allow).
.IP 
The way rsync disables the use of symlinks is to prefix each one with
the string \(dq\&/rsyncd\-munged/\(dq\&.  This prevents the links from being used
as long as that directory does not exist.  When this parameter is enabled,
rsync will refuse to run if that path is a directory or a symlink to
a directory.  When using the \(dq\&munge symlinks\(dq\& parameter in a chroot area
that has an inside\-chroot path of \(dq\&/\(dq\&, you should add \(dq\&/rsyncd\-munged/\(dq\&
to the exclude setting for the module so that
a user can\(cq\&t try to create it.
.IP 
Note:  rsync makes no attempt to verify that any pre\-existing symlinks in
the module\(cq\&s hierarchy are as safe as you want them to be (unless, of
course, it just copied in the whole hierarchy).  If you setup an rsync
daemon on a new area or locally add symlinks, you can manually protect your
symlinks from being abused by prefixing \(dq\&/rsyncd\-munged/\(dq\& to the start of
every symlink\(cq\&s value.  There is a perl script in the support directory
of the source code named \(dq\&munge\-symlinks\(dq\& that can be used to add or remove
this prefix from your symlinks.
.IP 
When this parameter is disabled on a writable module and \(dq\&use chroot\(dq\& is off
(or the inside\-chroot path is not \(dq\&/\(dq\&),
incoming symlinks will be modified to drop a leading slash and to remove \(dq\&..\(dq\&
path elements that rsync believes will allow a symlink to escape the module\(cq\&s
hierarchy.  There are tricky ways to work around this, though, so you had
better trust your users if you choose this combination of parameters.
.IP 
.IP "\fBcharset\fP"
This specifies the name of the character set in which the
module\(cq\&s filenames are stored.  If the client uses an \fB\-\-iconv\fP option,
the daemon will use the value of the \(dq\&charset\(dq\& parameter regardless of the
character set the client actually passed.  This allows the daemon to
support charset conversion in a chroot module without extra files in the
chroot area, and also ensures that name\-translation is done in a consistent
manner.  If the \(dq\&charset\(dq\& parameter is not set, the \fB\-\-iconv\fP option is
refused, just as if \(dq\&iconv\(dq\& had been specified via \(dq\&refuse options\(dq\&.
.IP 
If you wish to force users to always use \fB\-\-iconv\fP for a particular
module, add \(dq\&no\-iconv\(dq\& to the \(dq\&refuse options\(dq\& parameter.  Keep in mind
that this will restrict access to your module to very new rsync clients.
.IP 
.IP "\fBmax connections\fP"
This parameter allows you to
specify the maximum number of simultaneous connections you will allow.
Any clients connecting when the maximum has been reached will receive a
message telling them to try later.  The default is 0, which means no limit.
A negative value disables the module.
See also the \(dq\&lock file\(dq\& parameter.
.IP 
.IP "\fBlog file\fP"
When the \(dq\&log file\(dq\& parameter is set to a non\-empty
string, the rsync daemon will log messages to the indicated file rather
than using syslog. This is particularly useful on systems (such as AIX)
where 
\f(CWsyslog()\fP
doesn\(cq\&t work for chrooted programs.  The file is
opened before 
\f(CWchroot()\fP
is called, allowing it to be placed outside
the transfer.  If this value is set on a per\-module basis instead of
globally, the global log will still contain any authorization failures
or config\-file error messages.
.IP 
If the daemon fails to open the specified file, it will fall back to
using syslog and output an error about the failure.  (Note that the
failure to open the specified log file used to be a fatal error.)
.IP 
This setting can be overridden by using the \fB\-\-log\-file=FILE\fP or
\fB\-\-dparam=logfile=FILE\fP command\-line options.  The former overrides
all the log\-file parameters of the daemon and all module settings.
The latter sets the daemon\(cq\&s log file and the default for all the
modules, which still allows modules to override the default setting.
.IP 
.IP "\fBsyslog facility\fP"
This parameter allows you to
specify the syslog facility name to use when logging messages from the
rsync daemon. You may use any standard syslog facility name which is
defined on your system. Common names are auth, authpriv, cron, daemon,
ftp, kern, lpr, mail, news, security, syslog, user, uucp, local0,
local1, local2, local3, local4, local5, local6 and local7. The default
is daemon.  This setting has no effect if the \(dq\&log file\(dq\& setting is a
non\-empty string (either set in the per\-modules settings, or inherited
from the global settings).
.IP 
.IP "\fBmax verbosity\fP"
This parameter allows you to control
the maximum amount of verbose information that you\(cq\&ll allow the daemon to
generate (since the information goes into the log file). The default is 1,
which allows the client to request one level of verbosity.
.IP 
This also affects the user\(cq\&s ability to request higher levels of \fB\-\-info\fP and
\fB\-\-debug\fP logging.  If the max value is 2, then no info and/or debug value
that is higher than what would be set by \fB\-vv\fP will be honored by the daemon
in its logging.  To see how high of a verbosity level you need to accept for a
particular info/debug level, refer to \(dq\&rsync \-\-info=help\(dq\& and \(dq\&rsync \-\-debug=help\(dq\&.
For instance, it takes max\-verbosity 4 to be able to output debug TIME2 and FLIST3.
.IP 
.IP "\fBlock file\fP"
This parameter specifies the file to use to
support the \(dq\&max connections\(dq\& parameter. The rsync daemon uses record
locking on this file to ensure that the max connections limit is not
exceeded for the modules sharing the lock file.
The default is \f(CW/var/run/rsyncd.lock\fP.
.IP 
.IP "\fBread only\fP"
This parameter determines whether clients
will be able to upload files or not. If \(dq\&read only\(dq\& is true then any
attempted uploads will fail. If \(dq\&read only\(dq\& is false then uploads will
be possible if file permissions on the daemon side allow them. The default
is for all modules to be read only.
.IP 
Note that \(dq\&auth users\(dq\& can override this setting on a per\-user basis.
.IP 
.IP "\fBwrite only\fP"
This parameter determines whether clients
will be able to download files or not. If \(dq\&write only\(dq\& is true then any
attempted downloads will fail. If \(dq\&write only\(dq\& is false then downloads
will be possible if file permissions on the daemon side allow them.  The
default is for this parameter to be disabled.
.IP 
.IP "\fBlist\fP"
This parameter determines whether this module is
listed when the client asks for a listing of available modules.  In addition,
if this is false, the daemon will pretend the module does not exist
when a client denied by \(dq\&hosts allow\(dq\& or \(dq\&hosts deny\(dq\& attempts to access it.
Realize that if \(dq\&reverse lookup\(dq\& is disabled globally but enabled for the
module, the resulting reverse lookup to a potentially client\-controlled DNS
server may still reveal to the client that it hit an existing module.
The default is for modules to be listable.
.IP 
.IP "\fBuid\fP"
This parameter specifies the user name or user ID that
file transfers to and from that module should take place as when the daemon
was run as root. In combination with the \(dq\&gid\(dq\& parameter this determines what
file permissions are available. The default when run by a super\-user is to
switch to the system\(cq\&s \(dq\&nobody\(dq\& user.  The default for a non\-super\-user is to
not try to change the user.  See also the \(dq\&gid\(dq\& parameter.
.IP 
The RSYNC_USER_NAME environment variable may be used to request that rsync run
as the authorizing user.  For example, if you want a rsync to run as the same
user that was received for the rsync authentication, this setup is useful:
.IP 
.nf 
    uid = %RSYNC_USER_NAME%
    gid = * 
.fi 

.IP 
.IP "\fBgid\fP"
This parameter specifies one or more group names/IDs that will be
used when accessing the module.  The first one will be the default group, and
any extra ones be set as supplemental groups.  You may also specify a \(dq\&*\(dq\& as
the first gid in the list, which will be replaced by all the normal groups for
the transfer\(cq\&s user (see \(dq\&uid\(dq\&).  The default when run by a super\-user is to
switch to your OS\(cq\&s \(dq\&nobody\(dq\& (or perhaps \(dq\&nogroup\(dq\&) group with no other
supplementary groups.  The default for a non\-super\-user is to not change any
group attributes (and indeed, your OS may not allow a non\-super\-user to try to
change their group settings).
.IP 
.IP "\fBfake super\fP"
Setting \(dq\&fake super = yes\(dq\& for a module causes the
daemon side to behave as if the \fB\-\-fake\-super\fP command\-line option had
been specified.  This allows the full attributes of a file to be stored
without having to have the daemon actually running as root.
.IP 
.IP "\fBfilter\fP"
The daemon has its own filter chain that determines what files
it will let the client access.  This chain is not sent to the client and is
independent of any filters the client may have specified.  Files excluded by
the daemon filter chain (\fBdaemon\-excluded\fP files) are treated as non\-existent
if the client tries to pull them, are skipped with an error message if the
client tries to push them (triggering exit code 23), and are never deleted from
the module.  You can use daemon filters to prevent clients from downloading or
tampering with private administrative files, such as files you may add to
support uid/gid name translations.
.IP 
The daemon filter chain is built from the \(dq\&filter\(dq\&, \(dq\&include from\(dq\&, \(dq\&include\(dq\&,
\(dq\&exclude from\(dq\&, and \(dq\&exclude\(dq\& parameters, in that order of priority.  Anchored
patterns are anchored at the root of the module.  To prevent access to an
entire subtree, for example, \(dq\&/secret\(dq\&, you \fImust\fP exclude everything in the
subtree; the easiest way to do this is with a triple\-star pattern like
\(dq\&/secret/***\(dq\&.
.IP 
The \(dq\&filter\(dq\& parameter takes a space\-separated list of daemon filter rules,
though it is smart enough to know not to split a token at an internal space in
a rule (e.g. \(dq\&\- /foo  \- /bar\(dq\& is parsed as two rules).  You may specify one or
more merge\-file rules using the normal syntax.  Only one \(dq\&filter\(dq\& parameter can
apply to a given module in the config file, so put all the rules you want in a
single parameter.  Note that per\-directory merge\-file rules do not provide as
much protection as global rules, but they can be used to make \fB\-\-delete\fP work
better during a client download operation if the per\-dir merge files are
included in the transfer and the client requests that they be used.
.IP 
.IP "\fBexclude\fP"
This parameter takes a space\-separated list of daemon
exclude patterns.  As with the client \fB\-\-exclude\fP option, patterns can be
qualified with \(dq\&\- \(dq\& or \(dq\&+ \(dq\& to explicitly indicate exclude/include.  Only one
\(dq\&exclude\(dq\& parameter can apply to a given module.  See the \(dq\&filter\(dq\& parameter
for a description of how excluded files affect the daemon.
.IP 
.IP "\fBinclude\fP"
Use an \(dq\&include\(dq\& to override the effects of the \(dq\&exclude\(dq\&
parameter.  Only one \(dq\&include\(dq\& parameter can apply to a given module.  See the
\(dq\&filter\(dq\& parameter for a description of how excluded files affect the daemon.
.IP 
.IP "\fBexclude from\fP"
This parameter specifies the name of a file
on the daemon that contains daemon exclude patterns, one per line.  Only one
\(dq\&exclude from\(dq\& parameter can apply to a given module; if you have multiple
exclude\-from files, you can specify them as a merge file in the \(dq\&filter\(dq\&
parameter.  See the \(dq\&filter\(dq\& parameter for a description of how excluded files
affect the daemon.
.IP 
.IP "\fBinclude from\fP"
Analogue of \(dq\&exclude from\(dq\& for a file of daemon include
patterns.  Only one \(dq\&include from\(dq\& parameter can apply to a given module.  See
the \(dq\&filter\(dq\& parameter for a description of how excluded files affect the
daemon.
.IP 
.IP "\fBincoming chmod\fP"
This parameter allows you to specify a set of
comma\-separated chmod strings that will affect the permissions of all
incoming files (files that are being received by the daemon).  These
changes happen after all other permission calculations, and this will
even override destination\-default and/or existing permissions when the
client does not specify \fB\-\-perms\fP.
See the description of the \fB\-\-chmod\fP rsync option and the \fBchmod\fP(1)
manpage for information on the format of this string.
.IP 
.IP "\fBoutgoing chmod\fP"
This parameter allows you to specify a set of
comma\-separated chmod strings that will affect the permissions of all
outgoing files (files that are being sent out from the daemon).  These
changes happen first, making the sent permissions appear to be different
than those stored in the filesystem itself.  For instance, you could
disable group write permissions on the server while having it appear to
be on to the clients.
See the description of the \fB\-\-chmod\fP rsync option and the \fBchmod\fP(1)
manpage for information on the format of this string.
.IP 
.IP "\fBauth users\fP"
This parameter specifies a comma and/or space\-separated
list of authorization rules.  In its simplest form, you list the usernames
that will be allowed to connect to
this module. The usernames do not need to exist on the local
system. The rules may contain shell wildcard characters that will be matched
against the username provided by the client for authentication. If
\(dq\&auth users\(dq\& is set then the client will be challenged to supply a
username and password to connect to the module. A challenge response
authentication protocol is used for this exchange. The plain text
usernames and passwords are stored in the file specified by the
\(dq\&secrets file\(dq\& parameter. The default is for all users to be able to
connect without a password (this is called \(dq\&anonymous rsync\(dq\&).
.IP 
In addition to username matching, you can specify groupname matching via a \(cq\&@\(cq\&
prefix.  When using groupname matching, the authenticating username must be a
real user on the system, or it will be assumed to be a member of no groups.
For example, specifying \(dq\&@rsync\(dq\& will match the authenticating user if the
named user is a member of the rsync group.
.IP 
Finally, options may be specified after a colon (:).  The options allow you to
\(dq\&deny\(dq\& a user or a group, set the access to \(dq\&ro\(dq\& (read\-only), or set the access
to \(dq\&rw\(dq\& (read/write).  Setting an auth\-rule\-specific ro/rw setting overrides
the module\(cq\&s \(dq\&read only\(dq\& setting.
.IP 
Be sure to put the rules in the order you want them to be matched, because the
checking stops at the first matching user or group, and that is the only auth
that is checked.  For example:
.IP 
.nf 
  auth users = joe:deny @guest:deny admin:rw @rsync:ro susan joe sam 
.fi 

.IP 
In the above rule, user joe will be denied access no matter what.  Any user
that is in the group \(dq\&guest\(dq\& is also denied access.  The user \(dq\&admin\(dq\& gets
access in read/write mode, but only if the admin user is not in group \(dq\&guest\(dq\&
(because the admin user\-matching rule would never be reached if the user is in
group \(dq\&guest\(dq\&).  Any other user who is in group \(dq\&rsync\(dq\& will get read\-only
access.  Finally, users susan, joe, and sam get the ro/rw setting of the
module, but only if the user didn\(cq\&t match an earlier group\-matching rule.
.IP 
See the description of the secrets file for how you can have per\-user passwords
as well as per\-group passwords.  It also explains how a user can authenticate
using their user password or (when applicable) a group password, depending on
what rule is being authenticated.
.IP 
See also the section entitled \(dq\&USING RSYNC\-DAEMON FEATURES VIA A REMOTE
SHELL CONNECTION\(dq\& in \fBrsync\fP(1) for information on how handle an
rsyncd.conf\-level username that differs from the remote\-shell\-level
username when using a remote shell to connect to an rsync daemon.
.IP 
.IP "\fBsecrets file\fP"
This parameter specifies the name of a file that contains
the username:password and/or @groupname:password pairs used for authenticating
this module. This file is only consulted if the \(dq\&auth users\(dq\& parameter is
specified.  The file is line\-based and contains one name:password pair per
line.  Any line has a hash (#) as the very first character on the line is
considered a comment and is skipped.  The passwords can contain any characters
but be warned that many operating systems limit the length of passwords that
can be typed at the client end, so you may find that passwords longer than 8
characters don\(cq\&t work.
.IP 
The use of group\-specific lines are only relevant when the module is being
authorized using a matching \(dq\&@groupname\(dq\& rule.  When that happens, the user
can be authorized via either their \(dq\&username:password\(dq\& line or the
\(dq\&@groupname:password\(dq\& line for the group that triggered the authentication.
.IP 
It is up to you what kind of password entries you want to include, either
users, groups, or both.  The use of group rules in \(dq\&auth users\(dq\& does not
require that you specify a group password if you do not want to use shared
passwords.
.IP 
There is no default for the \(dq\&secrets file\(dq\& parameter, you must choose a name
(such as \f(CW/etc/rsyncd.secrets\fP).  The file must normally not be readable
by \(dq\&other\(dq\&; see \(dq\&strict modes\(dq\&.  If the file is not found or is rejected, no
logins for a \(dq\&user auth\(dq\& module will be possible.
.IP 
.IP "\fBstrict modes\fP"
This parameter determines whether or not
the permissions on the secrets file will be checked.  If \(dq\&strict modes\(dq\& is
true, then the secrets file must not be readable by any user ID other
than the one that the rsync daemon is running under.  If \(dq\&strict modes\(dq\& is
false, the check is not performed.  The default is true.  This parameter
was added to accommodate rsync running on the Windows operating system.
.IP 
.IP "\fBhosts allow\fP"
This parameter allows you to specify a
list of patterns that are matched against a connecting clients
hostname and IP address. If none of the patterns match then the
connection is rejected.
.IP 
Each pattern can be in one of five forms:
.IP 
.RS 
.IP o 
a dotted decimal IPv4 address of the form a.b.c.d, or an IPv6 address
of the form a:b:c::d:e:f. In this case the incoming machine\(cq\&s IP address
must match exactly.
.IP o 
an address/mask in the form ipaddr/n where ipaddr is the IP address
and n is the number of one bits in the netmask.  All IP addresses which
match the masked IP address will be allowed in.
.IP o 
an address/mask in the form ipaddr/maskaddr where ipaddr is the
IP address and maskaddr is the netmask in dotted decimal notation for IPv4,
or similar for IPv6, e.g. ffff:ffff:ffff:ffff:: instead of /64. All IP
addresses which match the masked IP address will be allowed in.
.IP o 
a hostname pattern using wildcards. If the hostname of the connecting IP
(as determined by a reverse lookup) matches the wildcarded name (using the
same rules as normal unix filename matching), the client is allowed in.  This
only works if \(dq\&reverse lookup\(dq\& is enabled (the default).
.IP o 
a hostname. A plain hostname is matched against the reverse DNS of the
connecting IP (if \(dq\&reverse lookup\(dq\& is enabled), and/or the IP of the given
hostname is matched against the connecting IP (if \(dq\&forward lookup\(dq\& is
enabled, as it is by default).  Any match will be allowed in.
.RE

.IP 
Note IPv6 link\-local addresses can have a scope in the address specification:
.IP 
.RS 
\f(CW    fe80::1%link1\fP
.br 
\f(CW    fe80::%link1/64\fP
.br 
\f(CW    fe80::%link1/ffff:ffff:ffff:ffff::\fP
.br 
.RE

.IP 
You can also combine \(dq\&hosts allow\(dq\& with a separate \(dq\&hosts deny\(dq\&
parameter. If both parameters are specified then the \(dq\&hosts allow\(dq\& parameter is
checked first and a match results in the client being able to
connect. The \(dq\&hosts deny\(dq\& parameter is then checked and a match means
that the host is rejected. If the host does not match either the
\(dq\&hosts allow\(dq\& or the \(dq\&hosts deny\(dq\& patterns then it is allowed to
connect.
.IP 
The default is no \(dq\&hosts allow\(dq\& parameter, which means all hosts can connect.
.IP 
.IP "\fBhosts deny\fP"
This parameter allows you to specify a
list of patterns that are matched against a connecting clients
hostname and IP address. If the pattern matches then the connection is
rejected. See the \(dq\&hosts allow\(dq\& parameter for more information.
.IP 
The default is no \(dq\&hosts deny\(dq\& parameter, which means all hosts can connect.
.IP 
.IP "\fBreverse lookup\fP"
Controls whether the daemon performs a reverse lookup
on the client\(cq\&s IP address to determine its hostname, which is used for
\(dq\&hosts allow\(dq\&/\(dq\&hosts deny\(dq\& checks and the \(dq\&%h\(dq\& log escape.  This is enabled by
default, but you may wish to disable it to save time if you know the lookup will
not return a useful result, in which case the daemon will use the name
\(dq\&UNDETERMINED\(dq\& instead.
.IP 
If this parameter is enabled globally (even by default), rsync performs the
lookup as soon as a client connects, so disabling it for a module will not
avoid the lookup.  Thus, you probably want to disable it globally and then
enable it for modules that need the information.
.IP 
.IP "\fBforward lookup\fP"
Controls whether the daemon performs a forward lookup
on any hostname specified in an hosts allow/deny setting.  By default this is
enabled, allowing the use of an explicit hostname that would not be returned
by reverse DNS of the connecting IP.
.IP 
.IP "\fBignore errors\fP"
This parameter tells rsyncd to
ignore I/O errors on the daemon when deciding whether to run the delete
phase of the transfer. Normally rsync skips the \fB\-\-delete\fP step if any
I/O errors have occurred in order to prevent disastrous deletion due
to a temporary resource shortage or other I/O error. In some cases this
test is counter productive so you can use this parameter to turn off this
behavior.
.IP 
.IP "\fBignore nonreadable\fP"
This tells the rsync daemon to completely
ignore files that are not readable by the user. This is useful for
public archives that may have some non\-readable files among the
directories, and the sysadmin doesn\(cq\&t want those files to be seen at all.
.IP 
.IP "\fBtransfer logging\fP"
This parameter enables per\-file
logging of downloads and uploads in a format somewhat similar to that
used by ftp daemons.  The daemon always logs the transfer at the end, so
if a transfer is aborted, no mention will be made in the log file.
.IP 
If you want to customize the log lines, see the \(dq\&log format\(dq\& parameter.
.IP 
.IP "\fBlog format\fP"
This parameter allows you to specify the
format used for logging file transfers when transfer logging is enabled.
The format is a text string containing embedded single\-character escape
sequences prefixed with a percent (%) character.  An optional numeric
field width may also be specified between the percent and the escape
letter (e.g. \(dq\&\fB%\-50n %8l %07p\fP\(dq\&).
In addition, one or more apostrophes may be specified prior to a numerical
escape to indicate that the numerical value should be made more human\-readable.
The 3 supported levels are the same as for the \fB\-\-human\-readable\fP
command\-line option, though the default is for human\-readability to be off.
Each added apostrophe increases the level (e.g. \(dq\&\fB%'\&'\&l %'\&b %f\fP\(dq\&).
.IP 
The default log format is \(dq\&%o %h [%a] %m (%u) %f %l\(dq\&, and a \(dq\&%t [%p] \(dq\&
is always prefixed when using the \(dq\&log file\(dq\& parameter.
(A perl script that will summarize this default log format is included
in the rsync source code distribution in the \(dq\&support\(dq\& subdirectory:
rsyncstats.)
.IP 
The single\-character escapes that are understood are as follows:
.IP 
.RS 
.IP o 
%a the remote IP address (only available for a daemon)
.IP o 
%b the number of bytes actually transferred
.IP o 
%B the permission bits of the file (e.g. rwxrwxrwt)
.IP o 
%c the total size of the block checksums received for the basis file (only when sending)
.IP o 
%C the full\-file MD5 checksum if \fB\-\-checksum\fP is enabled or a file was transferred (only for protocol 30 or above).
.IP o 
%f the filename (long form on sender; no trailing \(dq\&/\(dq\&)
.IP o 
%G the gid of the file (decimal) or \(dq\&DEFAULT\(dq\&
.IP o 
%h the remote host name (only available for a daemon)
.IP o 
%i an itemized list of what is being updated
.IP o 
%l the length of the file in bytes
.IP o 
%L the string \(dq\& \-> SYMLINK\(dq\&, \(dq\& => HARDLINK\(dq\&, or \(dq\&\(dq\& (where \fBSYMLINK\fP or \fBHARDLINK\fP is a filename)
.IP o 
%m the module name
.IP o 
%M the last\-modified time of the file
.IP o 
%n the filename (short form; trailing \(dq\&/\(dq\& on dir)
.IP o 
%o the operation, which is \(dq\&send\(dq\&, \(dq\&recv\(dq\&, or \(dq\&del.\(dq\& (the latter includes the trailing period)
.IP o 
%p the process ID of this rsync session
.IP o 
%P the module path
.IP o 
%t the current date time
.IP o 
%u the authenticated username or an empty string
.IP o 
%U the uid of the file (decimal)
.RE

.IP 
For a list of what the characters mean that are output by \(dq\&%i\(dq\&, see the
\fB\-\-itemize\-changes\fP option in the rsync manpage.
.IP 
Note that some of the logged output changes when talking with older
rsync versions.  For instance, deleted files were only output as verbose
messages prior to rsync 2.6.4.
.IP 
.IP "\fBtimeout\fP"
This parameter allows you to override the
clients choice for I/O timeout for this module. Using this parameter you
can ensure that rsync won\(cq\&t wait on a dead client forever. The timeout
is specified in seconds. A value of zero means no timeout and is the
default. A good choice for anonymous rsync daemons may be 600 (giving
a 10 minute timeout).
.IP 
.IP "\fBrefuse options\fP"
This parameter allows you to
specify a space\-separated list of rsync command line options that will
be refused by your rsync daemon.
You may specify the full option name, its one\-letter abbreviation, or a
wild\-card string that matches multiple options.
For example, this would refuse \fB\-\-checksum\fP (\fB\-c\fP) and all the various
delete options:
.IP 
.RS 
\f(CW    refuse options = c delete\fP
.RE

.IP 
The reason the above refuses all delete options is that the options imply
\fB\-\-delete\fP, and implied options are refused just like explicit options.
As an additional safety feature, the refusal of \(dq\&delete\(dq\& also refuses
\fBremove\-source\-files\fP when the daemon is the sender; if you want the latter
without the former, instead refuse \(dq\&delete\-*\(dq\& \-\- that refuses all the
delete modes without affecting \fB\-\-remove\-source\-files\fP.
.IP 
When an option is refused, the daemon prints an error message and exits.
To prevent all compression when serving files,
you can use \(dq\&dont compress = *\(dq\& (see below)
instead of \(dq\&refuse options = compress\(dq\& to avoid returning an error to a
client that requests compression.
.IP 
.IP "\fBdont compress\fP"
This parameter allows you to select
filenames based on wildcard patterns that should not be compressed
when pulling files from the daemon (no analogous parameter exists to
govern the pushing of files to a daemon).
Compression is expensive in terms of CPU usage, so it
is usually good to not try to compress files that won\(cq\&t compress well,
such as already compressed files.
.IP 
The \(dq\&dont compress\(dq\& parameter takes a space\-separated list of
case\-insensitive wildcard patterns. Any source filename matching one
of the patterns will not be compressed during transfer.
.IP 
See the \fB\-\-skip\-compress\fP parameter in the \fBrsync\fP(1) manpage for the list
of file suffixes that are not compressed by default.  Specifying a value
for the \(dq\&dont compress\(dq\& parameter changes the default when the daemon is
the sender.
.IP 
.IP "\fBpre\-xfer exec\fP, \fBpost\-xfer exec\fP"
You may specify a command to be run
before and/or after the transfer.  If the \fBpre\-xfer exec\fP command fails, the
transfer is aborted before it begins.  Any output from the script on stdout (up
to several KB) will be displayed to the user when aborting, but is NOT
displayed if the script returns success.  Any output from the script on stderr
goes to the daemon\(cq\&s stderr, which is typically discarded (though see
\-\-no\-detatch option for a way to see the stderr output, which can assist with
debugging).
.IP 
The following environment variables will be set, though some are
specific to the pre\-xfer or the post\-xfer environment:
.IP 
.RS 
.IP o 
\fBRSYNC_MODULE_NAME\fP: The name of the module being accessed.
.IP o 
\fBRSYNC_MODULE_PATH\fP: The path configured for the module.
.IP o 
\fBRSYNC_HOST_ADDR\fP: The accessing host\(cq\&s IP address.
.IP o 
\fBRSYNC_HOST_NAME\fP: The accessing host\(cq\&s name.
.IP o 
\fBRSYNC_USER_NAME\fP: The accessing user\(cq\&s name (empty if no user).
.IP o 
\fBRSYNC_PID\fP: A unique number for this transfer.
.IP o 
\fBRSYNC_REQUEST\fP: (pre\-xfer only) The module/path info specified
by the user.  Note that the user can specify multiple source files,
so the request can be something like \(dq\&mod/path1 mod/path2\(dq\&, etc.
.IP o 
\fBRSYNC_ARG#\fP: (pre\-xfer only) The pre\-request arguments are set
in these numbered values. RSYNC_ARG0 is always \(dq\&rsyncd\(dq\&, followed by
the options that were used in RSYNC_ARG1, and so on.  There will be a
value of \(dq\&.\(dq\& indicating that the options are done and the path args
are beginning \-\- these contain similar information to RSYNC_REQUEST,
but with values separated and the module name stripped off.
.IP o 
\fBRSYNC_EXIT_STATUS\fP: (post\-xfer only) the server side\(cq\&s exit value.
This will be 0 for a successful run, a positive value for an error that the
server generated, or a \-1 if rsync failed to exit properly.  Note that an
error that occurs on the client side does not currently get sent to the
server side, so this is not the final exit status for the whole transfer.
.IP o 
\fBRSYNC_RAW_STATUS\fP: (post\-xfer only) the raw exit value from 
\f(CWwaitpid()\fP
\&.
.RE

.IP 
Even though the commands can be associated with a particular module, they
are run using the permissions of the user that started the daemon (not the
module\(cq\&s uid/gid setting) without any chroot restrictions.
.IP 
.SH "CONFIG DIRECTIVES"

.PP 
There are currently two config directives available that allow a config file to
incorporate the contents of other files:  \fB&include\fP and \fB&merge\fP.  Both
allow a reference to either a file or a directory.  They differ in how
segregated the file\(cq\&s contents are considered to be.
.PP 
The \fB&include\fP directive treats each file as more distinct, with each one
inheriting the defaults of the parent file, starting the parameter parsing
as globals/defaults, and leaving the defaults unchanged for the parsing of
the rest of the parent file.
.PP 
The \fB&merge\fP directive, on the other hand, treats the file\(cq\&s contents as
if it were simply inserted in place of the directive, and thus it can set
parameters in a module started in another file, can affect the defaults for
other files, etc.
.PP 
When an \fB&include\fP or \fB&merge\fP directive refers to a directory, it will read
in all the \fB*.conf\fP or \fB*.inc\fP files (respectively) that are contained inside
that directory (without any
recursive scanning), with the files sorted into alpha order.  So, if you have a
directory named \(dq\&rsyncd.d\(dq\& with the files \(dq\&foo.conf\(dq\&, \(dq\&bar.conf\(dq\&, and
\(dq\&baz.conf\(dq\& inside it, this directive:
.PP 
.nf 
    &include /path/rsyncd.d 
.fi 

.PP 
would be the same as this set of directives:
.PP 
.nf 
    &include /path/rsyncd.d/bar.conf
    &include /path/rsyncd.d/baz.conf
    &include /path/rsyncd.d/foo.conf 
.fi 

.PP 
except that it adjusts as files are added and removed from the directory.
.PP 
The advantage of the \fB&include\fP directive is that you can define one or more
modules in a separate file without worrying about unintended side\-effects
between the self\-contained module files.
.PP 
The advantage of the \fB&merge\fP directive is that you can load config snippets
that can be included into multiple module definitions, and you can also set
global values that will affect connections (such as \fBmotd file\fP), or globals
that will affect other include files.
.PP 
For example, this is a useful /etc/rsyncd.conf file:
.PP 
.nf 
    port = 873
    log file = /var/log/rsync.log
    pid file = /var/lock/rsync.lock

    &merge /etc/rsyncd.d
    &include /etc/rsyncd.d 
.fi 

.PP 
This would merge any /etc/rsyncd.d/*.inc files (for global values that should
stay in effect), and then include any /etc/rsyncd.d/*.conf files (defining
modules without any global\-value cross\-talk).
.PP 
.SH "AUTHENTICATION STRENGTH"

.PP 
The authentication protocol used in rsync is a 128 bit MD4 based
challenge response system. This is fairly weak protection, though (with
at least one brute\-force hash\-finding algorithm publicly available), so
if you want really top\-quality security, then I recommend that you run
rsync over ssh.  (Yes, a future version of rsync will switch over to a
stronger hashing method.)
.PP 
Also note that the rsync daemon protocol does not currently provide any
encryption of the data that is transferred over the connection. Only
authentication is provided. Use ssh as the transport if you want
encryption.
.PP 
Future versions of rsync may support SSL for better authentication and
encryption, but that is still being investigated.
.PP 
.SH "EXAMPLES"

.PP 
A simple rsyncd.conf file that allow anonymous rsync to a ftp area at
\f(CW/home/ftp\fP would be:
.PP 
.nf 

[ftp]
        path = /home/ftp
        comment = ftp export area

.fi 

.PP 
A more sophisticated example would be:
.PP 
.nf 

uid = nobody
gid = nobody
use chroot = yes
max connections = 4
syslog facility = local5
pid file = /var/run/rsyncd.pid

[ftp]
        path = /var/ftp/./pub
        comment = whole ftp area (approx 6.1 GB)

[sambaftp]
        path = /var/ftp/./pub/samba
        comment = Samba ftp area (approx 300 MB)

[rsyncftp]
        path = /var/ftp/./pub/rsync
        comment = rsync ftp area (approx 6 MB)

[sambawww]
        path = /public_html/samba
        comment = Samba WWW pages (approx 240 MB)

[cvs]
        path = /data/cvs
        comment = CVS repository (requires authentication)
        auth users = tridge, susan
        secrets file = /etc/rsyncd.secrets

.fi 

.PP 
The /etc/rsyncd.secrets file would look something like this:
.PP 
.RS 
\f(CWtridge:mypass\fP
.br 
\f(CWsusan:herpass\fP
.br 
.RE

.PP 
.SH "FILES"

.PP 
/etc/rsyncd.conf or rsyncd.conf
.PP 
.SH "SEE ALSO"

.PP 
\fBrsync\fP(1)
.PP 
.SH "DIAGNOSTICS"

.PP 
.SH "BUGS"

.PP 
Please report bugs! The rsync bug tracking system is online at
http://rsync.samba.org/
.PP 
.SH "VERSION"

.PP 
This man page is current for version 3.1.2 of rsync.
.PP 
.SH "CREDITS"

.PP 
rsync is distributed under the GNU General Public License.  See the file
COPYING for details.
.PP 
The primary ftp site for rsync is
ftp://rsync.samba.org/pub/rsync.
.PP 
A WEB site is available at
http://rsync.samba.org/
.PP 
We would be delighted to hear from you if you like this program.
.PP 
This program uses the zlib compression library written by Jean\-loup
Gailly and Mark Adler.
.PP 
.SH "THANKS"

.PP 
Thanks to Warren Stanley for his original idea and patch for the rsync
daemon. Thanks to Karsten Thygesen for his many suggestions and
documentation!
.PP 
.SH "AUTHOR"

.PP 
rsync was written by Andrew Tridgell and Paul Mackerras.
Many people have later contributed to it.
.PP 
Mailing lists for support and development are available at
http://lists.samba.org