rsyncd.conf(5) User Commands rsyncd.conf(5)

NAME

rsyncd.conf - configuration file for rsync in daemon mode

SYNOPSIS

rsyncd.conf

The online version of this manpage (that includes cross-linking of
topics) is available at
<https://download.samba.org/pub/rsync/rsyncd.conf.5>.

DESCRIPTION

The rsyncd.conf file is the runtime configuration file for rsync when
run as an rsync daemon.

The rsyncd.conf file controls authentication, access, logging and
available modules.

FILE FORMAT

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 name = value.

The file is line-based -- that is, each newline-terminated line
represents either a comment, a module name or a parameter.

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.

Any line beginning 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's
content.)

Any line ending in a \ is "continued" on the next line in the
customary UNIX fashion.

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.

LAUNCHING THE RSYNC DAEMON

The rsync daemon is launched by specifying the --daemon option to
rsync.

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.

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 "rsync --daemon" from a suitable startup
script.

When run via inetd you should add a line like this to /etc/services:

rsync 873/tcp

and a single line something like this to /etc/inetd.conf:

rsync stream tcp nowait root /usr/bin/rsync rsyncd --daemon

Replace "/usr/bin/rsync" 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.

Note that you should not send the rsync daemon a HUP signal to force
it to reread the rsyncd.conf file. The file is re-read on each client
connection.

GLOBAL PARAMETERS

The first parameters in the file (before a [module] header) are the
global parameters:

motd file
This parameter allows you to specify a "message of the day"
(MOTD) 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
--dparam=motdfile=FILE command-line option when starting the
daemon.

pid file
This parameter tells the rsync daemon to write its process ID
to that file. The rsync keeps the file locked so that it can
know when it is safe to overwrite an existing file.

The filename can be overridden by the --dparam=pidfile=FILE
command-line option when starting the daemon.

port 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
--port command-line option.

address
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 --address
command-line option.

socket options
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 manpage for the setsockopt() 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 --sockopts command-line option.

listen backlog
You can override the default backlog value when the daemon
listens for connections. It defaults to 5.

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.

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 first 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 %%.

MODULE PARAMETERS

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.

There is also a special module name of "[global]" that does not
define a module but instead switches back to the global settings
context where default parameters can be specified. Because each
defined module gets its full set of parameters as a combination of
the default values that are set at that position in the config file
plus its own parameter list, the use of a "[global]" section can help
to maintain shared config values for multiple modules.

As with GLOBAL PARAMETERS, you may use references to environment
variables in the values of parameters. See that section for details.

comment
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.

path This parameter specifies the directory in the daemon's
filesystem to make available in this module. You must specify
this parameter for each module in rsyncd.conf.

If the value contains a "/./" element then the path will be
divided at that point into a chroot dir and an inner-chroot
subdir. If use chroot is set to false, though, the extraneous
dot dir is just cleaned out of the path. An example of this
idiom is:

path = /var/rsync/./module1

This will (when chrooting) chroot to "/var/rsync" and set the
inside-chroot path to "/module1".

You may base the path'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's
name in the path:

path = /home/%RSYNC_USER_NAME%

It is fine if the path includes internal spaces -- they will
be retained verbatim (which means that you shouldn'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.

use chroot
If "use chroot" is true, the rsync daemon will chroot to the
"path" 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).

If use chroot is not set, it defaults to trying to enable a
chroot but allows the daemon to continue (after logging a
warning) if it fails. The one exception to this is when a
module's path has a "/./" chroot divider in it -- this causes
an unset value to be treated as true for that module.

Prior to rsync 3.2.7, the default value was "true". The new
"unset" default makes it easier to setup an rsync daemon as a
non-root user or to run a daemon on a system where chroot
fails. Explicitly setting the value to "true" in rsyncd.conf
will always require the chroot to succeed.

It is also possible to specify a dot-dir in the module's
"path" to indicate that you want to chdir to the earlier part
of the path and then serve files from inside the latter part
of the path (with sanitizing and default symlink munging).
This can be useful if you need some library dirs inside the
chroot (typically for uid & gid lookups) but don't want to put
the lib dir into the top of the served path (even though they
can be hidden with an exclude directive). However, a better
choice for a modern rsync setup is to use a name converter"
and try to avoid inner lib dirs altogether. See also the
daemon chroot parameter, which causes rsync to chroot into its
own chroot area before doing any path-related chrooting.

If the daemon is serving the "/" dir (either directly or due
to being chrooted to the module's path), rsync does not do any
path sanitizing or (default) munging.

When it has to limit access to a particular subdir (either due
to chroot being disabled or having an inside-chroot path set),
rsync will munge symlinks (by default) and sanitize paths.
Those that dislike munged symlinks (and really, really trust
their users to not break out of the subdir) can disable the
symlink munging via the "munge symlinks" parameter.

When rsync is sanitizing paths, it trims ".." path elements
from args that it believes would escape the module hierarchy.
It also substitutes leading slashes in absolute paths with the
module's path (so that options such as --backup-dir &
--compare-dest interpret an absolute path as rooted in the
module's "path" dir).

When a chroot is in effect and the "name converter" parameter
is not set, the "numeric ids" parameter will default to being
enabled (disabling name lookups). This means that if you
manually setup name-lookup libraries in your chroot (instead
of using a name converter) that you need to explicitly set
numeric ids = false for rsync to do name lookups.

If you copy library resources into the module's chroot area,
you should protect them through your OS's normal user/group or
ACL settings (to prevent the rsync module's user from being
able to change them), and then hide them from the user's view
via "exclude" (see how in the discussion of that parameter).
However, it's easier and safer to setup a name converter.

daemon chroot
This parameter specifies a path to which the daemon will
chroot before beginning communication with clients. Module
paths (and any "use chroot" settings) will then be related to
this one. This lets you choose if you want the whole daemon to
be chrooted (with this setting), just the transfers to be
chrooted (with "use chroot"), or both. Keep in mind that the
"daemon chroot" area may need various OS/lib/etc files
installed to allow the daemon to function. By default the
daemon runs without any chrooting.

proxy protocol
When this parameter is enabled, all incoming connections must
start with a V1 or V2 proxy protocol header. If the header is
not found, the connection is closed.

Setting this to true requires a proxy server to forward source
IP information to rsync, allowing you to log proper IP/host
info and make use of client-oriented IP restrictions. The
default of false means that the IP information comes directly
from the socket's metadata. If rsync is not behind a proxy,
this should be disabled.

CAUTION: using this option can be dangerous if you do not
ensure that only the proxy is allowed to connect to the rsync
port. If any non-proxied connections are allowed through, the
client will be able to use a modified rsync to spoof any
remote IP address that they desire. You can lock this down
using something like iptables -uid-owner root rules (for
strict localhost access), various firewall rules, or you can
require password authorization so that any spoofing by users
will not grant extra access.

This setting is global. If you need some modules to require
this and not others, then you will need to setup multiple
rsync daemon processes on different ports.

name converter
This parameter lets you specify a program that will be run by
the rsync daemon to do user & group conversions between names
& ids. This script is started prior to any chroot being
setup, and runs as the daemon user (not the transfer user).
You can specify a fully qualified pathname or a program name
that is on the $PATH.

The program can be used to do normal user & group lookups
without having to put any extra files into the chroot area of
the module or you can do customized conversions.

The nameconvert program has access to all of the environment
variables that are described in the section on pre-xfer exec.
This is useful if you want to customize the conversion using
information about the module and/or the copy request.

There is a sample python script in the support dir named
"nameconvert" that implements the normal user & group lookups.
Feel free to customize it or just use it as documentation to
implement your own.

numeric ids
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 --numeric-ids 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 "uid") or for "fake super" to be configured.

A chroot-enabled module should not have this parameter set to
false unless you're using a "name converter" program or you'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.

munge symlinks
This parameter tells rsync to modify all symlinks in the same
way as the (non-daemon-affecting) --munge-links 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 "use chroot" is on
with an inside-chroot path of "/", OR if "daemon chroot" is
on, otherwise it is enabled.

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 "use chroot" is off, rsync can even be tricked
into showing or changing data that is outside the module's
path (as access-permissions allow).

The way rsync disables the use of symlinks is to prefix each
one with the string "/rsyncd-munged/". 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 "munge symlinks" parameter in a chroot area
that has an inside-chroot path of "/", you should add
"/rsyncd-munged/" to the exclude setting for the module so
that a user can't try to create it.

Note: rsync makes no attempt to verify that any pre-existing
symlinks in the module'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 "/rsyncd-munged/" to the start
of every symlink's value. There is a perl script in the
support directory of the source code named "munge-symlinks"
that can be used to add or remove this prefix from your
symlinks.

When this parameter is disabled on a writable module and "use
chroot" is off (or the inside-chroot path is not "/"),
incoming symlinks will be modified to drop a leading slash and
to remove ".." path elements that rsync believes will allow a
symlink to escape the module'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.

charset
This specifies the name of the character set in which the
module's filenames are stored. If the client uses an --iconv
option, the daemon will use the value of the "charset"
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 "charset" parameter is not set, the --iconv
option is refused, just as if "iconv" had been specified via
"refuse options".

If you wish to force users to always use --iconv for a
particular module, add "no-iconv" to the "refuse options"
parameter. Keep in mind that this will restrict access to
your module to very new rsync clients.

max connections
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 "lock file" parameter.

log file
When the "log file" 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 syslog() doesn't work for chrooted
programs. The file is opened before chroot() 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.

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.)

This setting can be overridden by using the --log-file=FILE or
--dparam=logfile=FILE command-line options. The former
overrides all the log-file parameters of the daemon and all
module settings. The latter sets the daemon's log file and
the default for all the modules, which still allows modules to
override the default setting.

syslog facility
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 "log
file" setting is a non-empty string (either set in the per-
modules settings, or inherited from the global settings).

syslog tag
This parameter allows you to specify the syslog tag to use
when logging messages from the rsync daemon. The default is
"rsyncd". This setting has no effect if the "log file"
setting is a non-empty string (either set in the per-modules
settings, or inherited from the global settings).

For example, if you wanted each authenticated user's name to
be included in the syslog tag, you could do something like
this:

syslog tag = rsyncd.%RSYNC_USER_NAME%

max verbosity
This parameter allows you to control the maximum amount of
verbose information that you'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.

This also affects the user's ability to request higher levels
of --info and --debug logging. If the max value is 2, then no
info and/or debug value that is higher than what would be set
by -vv 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 rsync --info=help and
rsync --debug=help. For instance, it takes max-verbosity 4 to
be able to output debug TIME2 and FLIST3.

lock file
This parameter specifies the file to use to support the "max
connections" 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 /var/run/rsyncd.lock.

read only
This parameter determines whether clients will be able to
upload files or not. If "read only" is true then any attempted
uploads will fail. If "read only" 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.

Note that "auth users" can override this setting on a per-user
basis.

write only
This parameter determines whether clients will be able to
download files or not. If "write only" is true then any
attempted downloads will fail. If "write only" 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.

Helpful hint: you probably want to specify "refuse options =
delete" for a write-only module.

open noatime
When set to True, this parameter tells the rsync daemon to
open files with the O_NOATIME flag (on systems that support
it) to avoid changing the access time of the files that are
being transferred. If your OS does not support the O_NOATIME
flag then rsync will silently ignore this option. Note also
that some filesystems are mounted to avoid updating the atime
on read access even without the O_NOATIME flag being set.

When set to False, this parameters ensures that files on the
server are not opened with O_NOATIME.

When set to Unset (the default) the user controls the setting
via --open-noatime.

list 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 "hosts allow" or "hosts
deny" attempts to access it. Realize that if "reverse lookup"
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.

uid 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 "gid"
parameter this determines what file permissions are available.
The default when run by a super-user is to switch to the
system's "nobody" user. The default for a non-super-user is
to not try to change the user. See also the "gid" parameter.

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:

uid = %RSYNC_USER_NAME%
gid = *

gid 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 "*" as the first gid in the
list, which will be replaced by all the normal groups for the
transfer's user (see "uid"). The default when run by a super-
user is to switch to your OS's "nobody" (or perhaps "nogroup")
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).

The specified list is normally split into tokens based on
spaces and commas. However, if the list starts with a comma,
then the list is only split on commas, which allows a group
name to contain a space. In either case any leading and/or
trailing whitespace is removed from the tokens and empty
tokens are ignored.

daemon uid
This parameter specifies a uid under which the daemon will
run. The daemon usually runs as user root, and when this is
left unset the user is left unchanged. See also the "uid"
parameter.

daemon gid
This parameter specifies a gid under which the daemon will
run. The daemon usually runs as group root, and when this is
left unset, the group is left unchanged. See also the "gid"
parameter.

fake super
Setting "fake super = yes" for a module causes the daemon side
to behave as if the --fake-super 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.

filter 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 (daemon-
excluded 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.

The daemon filter chain is built from the "filter", "include
from", "include", "exclude from", and "exclude" 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, "/secret", you must exclude everything in the
subtree; the easiest way to do this is with a triple-star
pattern like "/secret/***".

The "filter" 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. "- /foo - /bar" is
parsed as two rules). You may specify one or more merge-file
rules using the normal syntax. Only one "filter" 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 --delete 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.

exclude
This parameter takes a space-separated list of daemon exclude
patterns. As with the client --exclude option, patterns can
be qualified with "- " or "+ " to explicitly indicate
exclude/include. Only one "exclude" parameter can apply to a
given module. See the "filter" parameter for a description of
how excluded files affect the daemon.

include
Use an "include" to override the effects of the "exclude"
parameter. Only one "include" parameter can apply to a given
module. See the "filter" parameter for a description of how
excluded files affect the daemon.

exclude from
This parameter specifies the name of a file on the daemon that
contains daemon exclude patterns, one per line. Only one
"exclude from" parameter can apply to a given module; if you
have multiple exclude-from files, you can specify them as a
merge file in the "filter" parameter. See the "filter"
parameter for a description of how excluded files affect the
daemon.

include from
Analogue of "exclude from" for a file of daemon include
patterns. Only one "include from" parameter can apply to a
given module. See the "filter" parameter for a description of
how excluded files affect the daemon.

incoming chmod
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 --perms. See the
description of the --chmod rsync option and the chmod(1)
manpage for information on the format of this string.

outgoing chmod
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 --chmod rsync option and the chmod(1)
manpage for information on the format of this string.

auth users
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 "auth users" 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 "secrets file" parameter.
The default is for all users to be able to connect without a
password (this is called "anonymous rsync").

In addition to username matching, you can specify groupname
matching via a '@' 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 "@rsync" will match the authenticating user if the
named user is a member of the rsync group.

Finally, options may be specified after a colon (:). The
options allow you to "deny" a user or a group, set the access
to "ro" (read-only), or set the access to "rw" (read/write).
Setting an auth-rule-specific ro/rw setting overrides the
module's "read only" setting.

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:

auth users = joe:deny @guest:deny admin:rw @rsync:ro susan joe sam

In the above rule, user joe will be denied access no matter
what. Any user that is in the group "guest" is also denied
access. The user "admin" gets access in read/write mode, but
only if the admin user is not in group "guest" (because the
admin user-matching rule would never be reached if the user is
in group "guest"). Any other user who is in group "rsync"
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't match an earlier group-matching rule.

If you need to specify a user or group name with a space in
it, start your list with a comma to indicate that the list
should only be split on commas (though leading and trailing
whitespace will also be removed, and empty entries are just
ignored). For example:

auth users = , joe:deny, @Some Group:deny, admin:rw, @RO Group:ro

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.

See also the section entitled "USING RSYNC-DAEMON FEATURES VIA
A REMOTE SHELL CONNECTION" in rsync(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.

secrets file
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
"auth users" 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't
work.

The use of group-specific lines are only relevant when the
module is being authorized using a matching "@groupname" rule.
When that happens, the user can be authorized via either their
"username:password" line or the "@groupname:password" line for
the group that triggered the authentication.

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 "auth users" does not require that you specify a
group password if you do not want to use shared passwords.

There is no default for the "secrets file" parameter, you must
choose a name (such as /etc/rsyncd.secrets). The file must
normally not be readable by "other"; see "strict modes". If
the file is not found or is rejected, no logins for an "auth
users" module will be possible.

strict modes
This parameter determines whether or not the permissions on
the secrets file will be checked. If "strict modes" 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
"strict modes" is false, the check is not performed. The
default is true. This parameter was added to accommodate
rsync running on the Windows operating system.

hosts allow
This parameter allows you to specify a list of comma- and/or
whitespace-separated patterns that are matched against a
connecting client's hostname and IP address. If none of the
patterns match, then the connection is rejected.

Each pattern can be in one of six forms:

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's IP address must match exactly.

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.

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.

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 "reverse lookup" is enabled
(the default).

o a hostname. A plain hostname is matched against the
reverse DNS of the connecting IP (if "reverse lookup"
is enabled), and/or the IP of the given hostname is
matched against the connecting IP (if "forward lookup"
is enabled, as it is by default). Any match will be
allowed in.

o an '@' followed by a netgroup name, which will match if
the reverse DNS of the connecting IP is in the
specified netgroup.

Note IPv6 link-local addresses can have a scope in the address
specification:

fe80::1%link1
fe80::%link1/64
fe80::%link1/ffff:ffff:ffff:ffff::

You can also combine "hosts allow" with "hosts deny" as a way
to add exceptions to your deny list. When both parameters are
specified, the "hosts allow" parameter is checked first and a
match results in the client being able to connect. A non-
allowed host is then matched against the "hosts deny" list to
see if it should be rejected. A host that does not match
either list is allowed to connect.

The default is no "hosts allow" parameter, which means all
hosts can connect.

hosts deny
This parameter allows you to specify a list of comma- and/or
whitespace-separated patterns that are matched against a
connecting clients hostname and IP address. If the pattern
matches then the connection is rejected. See the "hosts allow"
parameter for more information.

The default is no "hosts deny" parameter, which means all
hosts can connect.

reverse lookup
Controls whether the daemon performs a reverse lookup on the
client's IP address to determine its hostname, which is used
for "hosts allow" & "hosts deny" checks and the "%h" 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
"UNDETERMINED" instead.

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.

forward lookup
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.

ignore errors
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 --delete 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.

ignore nonreadable
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't want those files to be
seen at all.

transfer logging
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.

If you want to customize the log lines, see the "log format"
parameter.

log format
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. "%-50n %8l %07p"). 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 --human-readable command-line option, though
the default is for human-readability to be off. Each added
apostrophe increases the level (e.g. "%''l %'b %f").

The default log format is "%o %h [%a] %m (%u) %f %l", and a
"%t [%p] " is always prefixed when using the "log file"
parameter. (A perl script that will summarize this default
log format is included in the rsync source code distribution
in the "support" subdirectory: rsyncstats.)

The single-character escapes that are understood are as
follows:

o %a the remote IP address (only available for a daemon)

o %b the number of bytes actually transferred

o %B the permission bits of the file (e.g. rwxrwxrwt)

o %c the total size of the block checksums received for
the basis file (only when sending)

o %C the full-file checksum if it is known for the file.
For older rsync protocols/versions, the checksum was
salted, and is thus not a useful value (and is not
displayed when that is the case). For the checksum to
output for a file, either the --checksum option must be
in-effect or the file must have been transferred
without a salted checksum being used. See the
--checksum-choice option for a way to choose the
algorithm.

o %f the filename (long form on sender; no trailing "/")

o %G the gid of the file (decimal) or "DEFAULT"

o %h the remote host name (only available for a daemon)

o %i an itemized list of what is being updated

o %l the length of the file in bytes

o %L the string " -> SYMLINK", " => HARDLINK", or ""
(where SYMLINK or HARDLINK is a filename)

o %m the module name

o %M the last-modified time of the file

o %n the filename (short form; trailing "/" on dir)

o %o the operation, which is "send", "recv", or "del."
(the latter includes the trailing period)

o %p the process ID of this rsync session

o %P the module path

o %t the current date time

o %u the authenticated username or an empty string

o %U the uid of the file (decimal)

For a list of what the characters mean that are output by
"%i", see the --itemize-changes option in the rsync manpage.

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.

timeout
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'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).

refuse options
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. Beginning in 3.2.0, you can also negate a match term
by starting it with a "!".

When an option is refused, the daemon prints an error message
and exits.

For example, this would refuse --checksum (-c) and all the
various delete options:

refuse options = c delete

The reason the above refuses all delete options is that the
options imply --delete, and implied options are refused just
like explicit options.

The use of a negated match allows you to fine-tune your
refusals after a wild-card, such as this:

refuse options = delete-* !delete-during

Negated matching can also turn your list of refused options
into a list of accepted options. To do this, begin the list
with a "*" (to refuse all options) and then specify one or
more negated matches to accept. For example:

refuse options = * !a !v !compress*

Don't worry that the "*" will refuse certain vital options
such as --dry-run, --server, --no-iconv, --seclude-args, etc.
These important options are not matched by wild-card, so they
must be overridden by their exact name. For instance, if
you're forcing iconv transfers you could use something like
this:

refuse options = * no-iconv !a !v

As an additional aid (beginning in 3.2.0), refusing (or
"!refusing") the "a" or "archive" option also affects all the
options that the --archive option implies (-rdlptgoD), but
only if the option is matched explicitly (not using a
wildcard). If you want to do something tricky, you can use
"archive*" to avoid this side-effect, but keep in mind that no
normal rsync client ever sends the actual archive option to
the server.

As an additional safety feature, the refusal of "delete" also
refuses remove-source-files when the daemon is the sender; if
you want the latter without the former, instead refuse
"delete-*" as that refuses all the delete modes without
affecting --remove-source-files. (Keep in mind that the
client's --delete option typically results in --delete-
during.)

When un-refusing delete options, you should either specify
"!delete*" (to accept all delete options) or specify a limited
set that includes "delete", such as:

refuse options = * !a !delete !delete-during

... whereas this accepts any delete option except --delete-
after:

refuse options = * !a !delete* delete-after

A note on refusing "compress": it may be better to set the
"dont compress" daemon parameter to "*" and ensure that
RSYNC_COMPRESS_LIST=zlib is set in the environment of the
daemon in order to disable compression silently instead of
returning an error that forces the client to remove the -z
option.

If you are un-refusing the compress option, you may want to
match "!compress*" if you also want to allow the --compress-
level option.

Note that the "copy-devices" & "write-devices" options are
refused by default, but they can be explicitly accepted with
"!copy-devices" and/or "!write-devices". The options "log-
file" and "log-file-format" are forcibly refused and cannot be
accepted.

Here are all the options that are not matched by wild-cards:

o --server: Required for rsync to even work.

o --rsh, -e: Required to convey compatibility flags to
the server.

o --out-format: This is required to convey output
behavior to a remote receiver. While rsync passes the
older alias --log-format for compatibility reasons,
this options should not be confused with --log-file-
format.

o --sender: Use "write only" parameter instead of
refusing this.

o --dry-run, -n: Who would want to disable this?

o --seclude-args, -s: Is the oldest arg-protection
method.

o --from0, -0: Makes it easier to accept/refuse --files-
from without affecting this helpful modifier.

o --iconv: This is auto-disabled based on "charset"
parameter.

o --no-iconv: Most transfers use this option.

o --checksum-seed: Is a fairly rare, safe option.

o --write-devices: Is non-wild but also auto-disabled.

dont compress
NOTE: This parameter currently has no effect except in one
instance: if it is set to "*" then it minimizes or disables
compression for all files (for those that don't want to refuse
the --compress option completely).

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 can be
expensive in terms of CPU usage, so it is usually good to not
try to compress files that won't compress well, such as
already compressed files.

The "dont compress" parameter takes a space-separated list of
case-insensitive wildcard patterns. Any source filename
matching one of the patterns will be compressed as little as
possible during the transfer. If the compression algorithm
has an "off" level, then no compression occurs for those
files. If an algorithms has the ability to change the level
in mid-stream, it will be minimized to reduce the CPU usage as
much as possible.

See the --skip-compress parameter in the rsync(1) manpage for
the list of file suffixes that are skipped by default if this
parameter is not set.

early exec, pre-xfer exec, post-xfer exec
You may specify a command to be run in the early stages of the
connection, or right before and/or after the transfer. If the
early exec or pre-xfer exec command returns an error code, the
transfer is aborted before it begins. Any output from the
pre-xfer exec command on stdout (up to several KB) will be
displayed to the user when aborting, but is not displayed if
the script returns success. The other programs cannot send
any text to the user. All output except for the pre-xfer exec
stdout goes to the corresponding daemon's stdout/stderr, which
is typically discarded. See the --no-detach option for a way
to see the daemon's output, which can assist with debugging.

Note that the early exec command runs before any part of the
transfer request is known except for the module name. This
helper script can be used to setup a disk mount or decrypt
some data into a module dir, but you may need to use lock file
and max connections to avoid concurrency issues. If the
client rsync specified the --early-input=FILE option, it can
send up to about 5K of data to the stdin of the early script.
The stdin will otherwise be empty.

Note that the post-xfer exec command is still run even if one
of the other scripts returns an error code. The pre-xfer exec
command will not be run, however, if the early exec command
fails.

The following environment variables will be set, though some
are specific to the pre-xfer or the post-xfer environment:

o RSYNC_MODULE_NAME: The name of the module being
accessed.

o RSYNC_MODULE_PATH: The path configured for the module.

o RSYNC_HOST_ADDR: The accessing host's IP address.

o RSYNC_HOST_NAME: The accessing host's name.

o RSYNC_USER_NAME: The accessing user's name (empty if no
user).

o RSYNC_PID: A unique number for this transfer.

o RSYNC_REQUEST: (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 "mod/path1 mod/path2", etc.

o RSYNC_ARG#: (pre-xfer only) The pre-request arguments
are set in these numbered values. RSYNC_ARG0 is always
"rsyncd", followed by the options that were used in
RSYNC_ARG1, and so on. There will be a value of "."
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.

o RSYNC_EXIT_STATUS: (post-xfer only) the server side'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.

o RSYNC_RAW_STATUS: (post-xfer only) the raw exit value
from waitpid().

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's uid/gid setting) without
any chroot restrictions.

These settings honor 2 environment variables: use RSYNC_SHELL
to set a shell to use when running the command (which
otherwise uses your system() call's default shell), and use
RSYNC_NO_XFER_EXEC to disable both options completely.

CONFIG DIRECTIVES

There are currently two config directives available that allow a
config file to incorporate the contents of other files: &include and
&merge. Both allow a reference to either a file or a directory.
They differ in how segregated the file's contents are considered to
be.

The &include 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.

The &merge directive, on the other hand, treats the file'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.

When an &include or &merge directive refers to a directory, it will
read in all the *.conf or *.inc 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 "rsyncd.d" with the files "foo.conf", "bar.conf", and
"baz.conf" inside it, this directive:

&include /path/rsyncd.d

would be the same as this set of directives:

&include /path/rsyncd.d/bar.conf
&include /path/rsyncd.d/baz.conf
&include /path/rsyncd.d/foo.conf

except that it adjusts as files are added and removed from the
directory.

The advantage of the &include 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.

The advantage of the &merge 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
motd file), or globals that will affect other include files.

For example, this is a useful /etc/rsyncd.conf file:

port = 873
log file = /var/log/rsync.log
pid file = /var/lock/rsync.lock

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

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).

AUTHENTICATION STRENGTH

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.)

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.

You can also make use of SSL/TLS encryption if you put rsync behind
an SSL proxy.

SSL/TLS Daemon Setup
When setting up an rsync daemon for access via SSL/TLS, you will need
to configure a TCP proxy (such as haproxy or nginx) as the front-end
that handles the encryption.

o You should limit the access to the backend-rsyncd port to only
allow the proxy to connect. If it is on the same host as the
proxy, then configuring it to only listen on localhost is a
good idea.

o You should consider turning on the proxy protocol rsync-daemon
parameter if your proxy supports sending that information.
The examples below assume that this is enabled.

An example haproxy setup is as follows:

frontend fe_rsync-ssl
bind :::874 ssl crt /etc/letsencrypt/example.com/combined.pem
mode tcp
use_backend be_rsync

backend be_rsync
mode tcp
server local-rsync 127.0.0.1:873 check send-proxy

An example nginx proxy setup is as follows:

stream {
server {
listen 874 ssl;
listen [::]:874 ssl;

ssl_certificate /etc/letsencrypt/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/example.com/privkey.pem;

proxy_pass localhost:873;
proxy_protocol on; # Requires rsyncd.conf "proxy protocol = true"
proxy_timeout 1m;
proxy_connect_timeout 5s;
}
}

If rsyncd should be accessible encrypted and unencrypted at the same
time make the proxy listen on port 873 as well and let it handle both
streams.

DAEMON CONFIG EXAMPLES

A simple rsyncd.conf file that allow anonymous rsync to a ftp area at
/home/ftp would be:

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

A more sophisticated example would be:

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

The /etc/rsyncd.secrets file would look something like this:

tridge:mypass
susan:herpass

FILES

/etc/rsyncd.conf or rsyncd.conf

SEE ALSO

rsync(1), rsync-ssl(1)

BUGS

Please report bugs! The rsync bug tracking system is online at
<https://rsync.samba.org/>.

VERSION

This manpage is current for version 3.4.1 of rsync.

CREDITS

Rsync is distributed under the GNU General Public License. See the
file COPYING for details.

An rsync web site is available at <https://rsync.samba.org/> and its
github project is <https://github.com/RsyncProject/rsync>.

THANKS

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

AUTHOR

Rsync was originally written by Andrew Tridgell and Paul Mackerras.
Many people from around the world have helped to maintain and improve
it.

Mailing lists for support and development are available at
<https://lists.samba.org/>.

rsyncd.conf from rsync 3.4.1 15 Jan 2025 rsyncd.conf(5)