Updated: 1 Feb 2000
- FILE FORMAT
- LAUNCHING THE RSYNC DAEMON
- GLOBAL OPTIONS
- MODULE OPTIONS
- AUTHENTICATION STRENGTH
- SEE ALSO
rsyncd.conf - configuration file for rsync server
The rsyncd.conf file is the runtime configuration file for rsync when
run with the --daemon option. When run in this way rsync becomes a
rsync server listening on TCP port 873. Connections from rsync clients
are accepted for either anonymous or authenticated rsync sessions.
The rsyncd.conf file controls authentication, access, logging and
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
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.
You can launch it either via inetd or as a stand-alone daemon. If run
as a daemon then just run the command "rsync --daemon" from a suitable
When run via inetd you should add a line like this to /etc/services:
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 server a HUP signal to force
it to reread the /etc/rsyncd.conf. The file is re-read on each client
The first parameters in the file (before a [module] header) are the
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
- 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 server. 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
- 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
special socket options are set.
After the global options 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 options for that module.
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.
The "path" option specifies the directory in the servers
filesystem to make available in this module. You must specify this option
for each module in /etc/rsyncd.conf.
- use chroot
If "use chroot" is true, the rsync server 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 and
of not being able to follow symbolic links outside of the new root path.
The default is to use chroot.
- max connections
The "max connections" option allows you to
specify the maximum number of simultaneous connections you will allow
to this module of your rsync server. 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.
- lock file
The "lock file" option specifies the file to use to
support the "max connections" option. The rsync server uses record
locking on this file to ensure that the max connections limit is not
exceeded. 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 server allow them. The default
is for all modules to be read only.
The "list" option determines if this module should be
listed when the client asks for a listing of available modules. By
setting this to false you can create hidden modules. The default is
for modules to be listable.
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 the user "nobody".
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 the
The "exclude" option allows you to specify a space
separated list of patterns to add to the exclude list. This is
equivalent to the client specifying these patterns with the --exclude
option except that the exclude list is not passed to the client and
thus only apply on the server. Only one "exclude" option may be
specified, but you can use "-" and "+" before patterns to specify
Note that this option is not designed with strong security in
mind, it is quite possible that a client may find a way to bypass this
exclude list. If you want to absolutely ensure that certain files
cannot be accessed then use the uid/gid options in combination with
- exclude from
The "exclude from" option specifies a filename
on the server that contains exclude patterns, one per line. This is
equivalent to the client specifying the --exclude-from option with a
equivalent file except that the resulting exclude patterns are not
passed to the client and thus only apply on the server. See also the
note about security for the exclude option above.
The "include" option allows you to specify a space
separated list of patterns which rsync should not exclude. This is
equivalent to the client specifying these patterns with the --include
option. 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 section of exclude patterns in the rsync man page for information
on the syntax of this option.
- include from
The "include from" option specifies a filename
on the server that contains include patterns, one per line. This is
equivalent to the client specifying the --include-from option with a
- 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. 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 are 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").
- 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).
- 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:
a dotted decimal IP address. In this case the incoming machines
IP address must match exactly.
a address/mask in the form a.b.c.d/n were n is the number of
one bits in in the netmask. All IP addresses which match the masked
IP address will be allowed in.
a address/mask in the form a.b.c.d/e.f.g.h where e.f.g.h is a
netmask in dotted decimal notation. All IP addresses which match the masked
IP address will be allowed in.
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.
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.
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
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 IO errors on the server when deciding whether to run the delete
phase of the transfer. Normally rsync skips the --delete step if any
IO errors have occurred in order to prevent disasterous deletion due
to a temporary resource shortage or other IO error. In some cases this
test is counter productive so you can use this option to turn off this
- transfer logging
The "transfer logging" option enables per-file
logging of downloads and uploads in a format somewhat similar to that
used by ftp daemons. If you want to customize the log formats look at
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.
The prefixes that are understood are:
- %h for the remote host name
- %a for the remote IP address
- %l for the length of the file in bytes
- %p for the process id of this rsync session
- %o for the operation, which is either "send" or "recv"
- %f for the filename
- %P for the module path
- %m for the module name
- %t for the current date time
- %u for the authenticated username (or the null string)
- %b for the number of bytes actually transferred
- %c when sending files this gives the number of checksum bytes
received for this file
The default log format is "%o %h [%a] %m (%u) %f %l", and a "%t [%p] "
is always added to the beginning when using the "log file" option.
A perl script called rsyncstats to summarize this format is included
in the rsync source code distribution.
The "timeout" option allows you to override the
clients choice for IO 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 servers 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 server. The full names of the options must be
used (i.e., you must use "checksum" not "c" to disable checksumming).
When an option is refused, the server 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
The authentication protocol used in rsync is a 128 bit MD4 based
challenge response system. Although I believe that no one has ever
demonstrated a brute-force break of this sort of system you should
realize that this is not a "military strength" authentication system.
It should be good enough for most purposes but if you want really top
quality security then I recommend that you run rsync over ssh.
Also note that the rsync server protocol does not currently provide any
encryption of the data that is transferred over the link. Only
authentication is provided. Use ssh as the transport if you want
Future versions of rsync may support SSL for better authentication and
encryption, but that is still being investigated.
A simple rsyncd.conf file that allow anonymous rsync to a ftp area at
/home/ftp would be:
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 = /etc/rsyncd.pid
The /etc/rsyncd.secrets file would look something like this:
path = /var/ftp/pub
comment = whole ftp area (approx 6.1 GB)
path = /var/ftp/pub/samba
comment = Samba ftp area (approx 300 MB)
path = /var/ftp/pub/rsync
comment = rsync ftp area (approx 6 MB)
path = /public_html/samba
comment = Samba WWW pages (approx 240 MB)
path = /data/cvs
comment = CVS repository (requires authentication)
auth users = tridge, susan
secrets file = /etc/rsyncd.secrets
The rsync server does not send all types of error messages to the
client. this means a client may be mystified as to why a transfer
failed. The error will have been logged by syslog on the server.
Please report bugs! The rsync bug tracking system is online at
This man page is current for version 2.0 of rsync
rsync is distributed under the GNU public license. See the file
COPYING for details.
The primary ftp site for rsync is
A WEB site is available at
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 to Warren Stanley for his original idea and patch for the rsync
server. Thanks to Karsten Thygesen for his many suggestions and
rsync was written by Andrew Tridgell and Paul Mackerras. They may be
contacted via email at email@example.com and