5:rsyncd.conf
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rsyncd.conf - configuration file for rsync in daemon mode
rsyncd.conf
Contents |
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.
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 appro-
priate 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 OPTIONS
The first parameters in the file (before a [module] header) are the global parameters.
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.
motd file
The "motd file" option allows you to specify a "message of the day" to display to clients on each connect.
This usually contains site information and any legal notices. The default is no motd file.
log file
The "log file" option tells the rsync daemon to log messages to that file rather than using syslog. This
is particularly useful on systems (such as AIX) where syslog() doesn't work for chrooted programs. If the
daemon fails to open to specified file, it will fall back to using syslog and output an error about the
failure. (Note that a failure to open the specified log file used to be a fatal error.)
pid file
The "pid file" option tells the rsync daemon to write its process ID to that file.
syslog facility
The "syslog facility" option 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. Com-
mon 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.
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 option 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 setsockopt() system call for details on some of the options you may be able to set. By default no spe-
cial socket options are set. These settings are superseded by the --sockopts command-line option.
slp refresh
This option is used to determine how long service advertisements are valid (measured in seconds), and is
only applicable if you have Service Location Protocol support compiled in. If this option is not set or is
set to zero, then service advertisements never time out. If this is set to less than 120 seconds, then 120
seconds is used. If it is set to more than 65535, then 65535 is used (which is a limitation of SLP).
Using 3600 (one hour) is a good number if you tend to change your configuration.
MODULE OPTIONS
After the global options you should define a number of modules, each module exports a directory tree as a sym-
bolic name. Modules are exported by specifying a module name in square brackets [module] followed by the options
for that module.
comment
The "comment" option 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 The "path" option specifies the directory in the daemon's filesystem to make available in this module.
You must specify this option for each module in rsyncd.conf.
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
usernames and groups (see below). When "use chroot" is false, for security reasons, symlinks may only be
relative paths pointing to other files within the root path, and leading slashes are removed from most
absolute paths (options such as --backup-dir, --compare-dest, etc. interpret an absolute path as rooted in
the module's "path" dir, just as if chroot was specified). The default for "use chroot" is true.
In order to preserve usernames and groupnames, rsync needs to be able to use the standard library func-
tions for looking up names and IDs (i.e. getpwuid(), getgrgid(), getpwname(), and getgrnam()). This
means a process in the chroot namespace will need to have access to the resources used by these library
functions (traditionally /etc/passwd and /etc/group). If these resources are not available, rsync will
only be able to copy the IDs, just as if the --numeric-ids option had been specified.
Note that you are free to setup user/group information in the chroot area differently from your normal
system. For example, you could abbreviate the list of users and groups. Also, you can protect this
information from being downloaded/uploaded by adding an exclude rule to the rsyncd.conf file (e.g.
"exclude = /etc/**"). Note that having the exclusion affect uploads is a relatively new feature in rsync,
so make sure your daemon is at least 2.6.3 to effect this. Also note that it is safest to exclude a
directory and all its contents combining the rule "/some/dir/" with the rule "/some/dir/**" just to be
sure that rsync will not allow deeper access to some of the excluded files inside the directory (rsync
tries to do this automatically, but you might as well specify both to be extra sure).
max connections
The "max connections" option 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. See also the "lock file" option.
max verbosity
The "max verbosity" option 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.
lock file
The "lock file" option specifies the file to use to support the "max connections" option. 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
The "read only" option 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.
write only
The "write only" option 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 option to be disabled.
list The "list" option determines if this module should be listed when the client asks for a listing of avail-
able modules. By setting this to false you can create hidden modules. The default is for modules to be
listable.
uid The "uid" option 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" option this determines what
file permissions are available. The default is uid -2, which is normally the user "nobody".
gid The "gid" option specifies the group name or group ID that file transfers to and from that module should
take place as when the daemon was run as root. This complements the "uid" option. The default is gid -2,
which is normally the group "nobody".
filter The "filter" option allows you to specify a space-separated list of filter rules that the daemon will not
allow to be read or written. This is only superficially equivalent to the client specifying these pat-
terns with the --filter option. Only one "filter" option may be specified, but it may contain as many
rules as you like, including merge-file rules. 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 when a client downloads
the daemon's files (if the per-dir merge files are included in the transfer).
exclude
The "exclude" option allows you to specify a space-separated list of patterns that the daemon will not
allow to be read or written. This is only superficially equivalent to the client specifying these pat-
terns with the --exclude option. Only one "exclude" option may be specified, but you can use "-" and "+"
before patterns to specify exclude/include.
Because this exclude list is not passed to the client it only applies on the daemon: that is, it excludes
files received by a client when receiving from a daemon and files deleted on a daemon when sending to a
daemon, but it doesn't exclude files from being deleted on a client when receiving from a daemon.
exclude from
The "exclude from" option specifies a filename on the daemon that contains exclude patterns, one per line.
This is only superficially equivalent to the client specifying the --exclude-from option with an equiva-
lent file. See the "exclude" option above.
include
The "include" option allows you to specify a space-separated list of patterns which rsync should not
exclude. This is only superficially equivalent to the client specifying these patterns with the --include
option because it applies only on the daemon. This is useful as it allows you to build up quite complex
exclude/include rules. Only one "include" option may be specified, but you can use "+" and "-" before
patterns to switch include/exclude. See the "exclude" option above.
include from
The "include from" option specifies a filename on the daemon that contains include patterns, one per line.
This is only superficially equivalent to the client specifying the --include-from option with a equivalent
file. See the "exclude" option above.
incoming chmod
This option 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 option 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
The "auth users" option specifies a comma and space-separated list of usernames that will be allowed to
connect to this module. The usernames do not need to exist on the local system. The usernames may also
contain shell wildcard characters. 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" option. The default is for all users to be able to connect without a password (this is called
"anonymous rsync").
See also the "CONNECTING TO AN RSYNC DAEMON OVER A REMOTE SHELL PROGRAM" section in rsync(1) for informa-
tion 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
The "secrets file" option specifies the name of a file that contains the username:password pairs used for
authenticating this module. This file is only consulted if the "auth users" option is specified. The file
is line based and contains username:password pairs separated by a single colon. Any line starting with a
hash (#) 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.
There is no default for the "secrets file" option, you must choose a name (such as /etc/rsyncd.secrets).
The file must normally not be readable by "other"; see "strict modes".
strict modes
The "strict modes" option 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 option was added to accommodate rsync running on the Windows operating system.
hosts allow
The "hosts allow" option 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.
Each pattern can be in one of five 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 net-
mask 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. The hostname as determined by a reverse lookup will be matched (case insensitive)
against the pattern. Only an exact match is allowed in.
o a hostname pattern using wildcards. These are matched using the same rules as normal unix filename
matching. If the pattern matches then the client is allowed in.
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 a separate "hosts deny" option. If both options are specified then
the "hosts allow" option s checked first and a match results in the client being able to connect. The
"hosts deny" option is then checked and a match means that the host is rejected. If the host does not
match either the "hosts allow" or the "hosts deny" patterns then it is allowed to connect.
The default is no "hosts allow" option, which means all hosts can connect.
hosts deny
The "hosts deny" option 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 "hosts
allow" option for more information.
The default is no "hosts deny" option, which means all hosts can connect.
ignore errors
The "ignore errors" option 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 option 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
The "transfer logging" option enables per-file logging of downloads and uploads in a format somewhat simi-
lar 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" option.
log format
The "log format" option 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").
The default log format is "%o %h [%a] %m (%u) %f %l", and a "%t [%p] " is always prefixed when using the
"log file" option. (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
o %b the number of bytes actually transferred
o %B the permission bits of the file (e.g. rwxrwxrwt)
o %c the checksum bytes received for this file (only when sending)
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
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
The "timeout" option allows you to override the clients choice for I/O timeout for this module. Using this
option 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
The "refuse options" option 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 abbrevia-
tion, or a wild-card string that matches multiple options. 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. As an additional safety feature, the refusal of "delete" also
refuses remove-sent-files when the daemon is the sender; if you want the latter without the former,
instead refuse "delete-*" -- that refuses all the delete modes without affecting --remove-sent-files.
When an option is refused, the daemon prints an error message and exits. To prevent all compression, you
can use "dont compress = *" (see below) instead of "refuse options = compress" to avoid returning an error
to a client that requests compression.
dont compress
The "dont compress" option allows you to select filenames based on wildcard patterns that should not be
compressed during transfer. Compression is 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" option takes a space-separated list of case-insensitive wildcard patterns. Any source
filename matching one of the patterns will not be compressed during transfer.
The default setting is *.gz *.tgz *.zip *.z *.rpm *.deb *.iso *.bz2 *.tbz
pre-xfer exec, post-xfer exec
You may specify a command to be run before and/or after the transfer. If the pre-xfer exec command fails,
the transfer is aborted before it begins.
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_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", and the last value contains a single period.
o RSYNC_EXIT_STATUS: (post-xfer only) rsync's exit value. This will be 0 for a successful run, a
positive value for an error that rsync returned (e.g. 23=partial xfer), or a -1 if rsync failed to
exit properly.
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.
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 trans-
ferred over the connection. Only authentication is provided. Use ssh as the transport if you want encryption.
Future versions of rsync may support SSL for better authentication and encryption, but that is still being inves-
tigated.
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 = no
max connections = 4
syslog facility = local5
pid file = /var/run/rsyncd.pid
slp refresh = 3600
[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
RELATED
rsync(1)
DIAGNOSTICS
BUGS
Please report bugs! The rsync bug tracking system is online at http://rsync.samba.org/
VERSION
This man page is current for version 2.6.8 of rsync.
CREDITS
rsync is distributed under the GNU public license. See the file COPYING for details.
The primary ftp site for rsync is ftp://rsync.samba.org/pub/rsync.
A WEB site is available at http://rsync.samba.org/
We would be delighted to hear from you if you like this program.
This program uses the zlib compression library written by Jean-loup Gailly and Mark Adler.
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!