Improved the "use chroot" discussion on ID mapping.

[rsync/rsync.git] / rsyncd.conf.yo

mailto(rsync-bugs@samba.org)
manpage(rsyncd.conf)(5)(1 Jan 2004)()()
manpagename(rsyncd.conf)(configuration file for rsync server)
manpagesynopsis()

rsyncd.conf

manpagedescription()

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

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

manpagesection(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. 

manpagesection(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.
If run from an rsync client via a remote shell (by specifying both the
"-e/--rsh" option and server mode with "::" or "rsync://"), the --daemon
option is automatically passed to the remote side.

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

quote(rsync           873/tcp)

and a single line something like this to /etc/inetd.conf:
    
quote(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 tt(rsyncd.conf) file. The file is re-read on each client
connection. 

manpagesection(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.

startdit()
dit(bf(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.

dit(bf(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.

dit(bf(pid file)) The "pid file" option tells the rsync daemon to write
its process id to that file.

dit(bf(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
is daemon. 

dit(bf(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.

enddit()


manpagesection(MODULE OPTIONS)

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.

startdit()

dit(bf(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.

dit(bf(path)) 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 tt(rsyncd.conf).

dit(bf(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, 
of not being able to follow symbolic links outside of the new root path
when reading, 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 absolute paths.  The default for
"use chroot" is true.

In order to preserve usernames and groupnames, rsync needs to be able to
lookup the IDs using getpuid() and getpgid().  This means that the chroot
area will need to have copies of your user/group information (edited, if
desired) inside the chroot tree for rsync to use (the traditional files
are /etc/passwd and /etc/group).  If the needed files are not available,
rsync will only be able to copy the IDs, just as if the --numeric-ids
option had been specified.

dit(bf(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.

dit(bf(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 for the modules sharing the lock file. 
The default is tt(/var/run/rsyncd.lock).

dit(bf(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.

dit(bf(list)) 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.

dit(bf(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".

dit(bf(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".

dit(bf(exclude)) The "exclude" option allows you to specify a space
separated list of patterns to add to the exclude list.
This is only superficially equivalent
to the client specifying these patterns 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 server: that is, it excludes files received by a client when receiving
from a server and files deleted on a server when sending to a server, but
it doesn't exclude files sent from a client when sending to a server or
files deleted on a client when receiving from a server.  

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
file permissions.

dit(bf(exclude from)) The "exclude from" option specifies a filename
on the server that contains exclude patterns, one per line.
This is only superficially equivalent
to the client specifying the --exclude-from option with an equivalent file.
See the "exclude" option above.

dit(bf(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 server.
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.

dit(bf(include from)) The "include from" option specifies a filename
on the server 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.

dit(bf(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 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").

See also the bf(CONNECTING TO AN RSYNC SERVER OVER A REMOTE SHELL
PROGRAM) section 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 a rsync server.

dit(bf(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 tt(/etc/rsyncd.secrets)).  The file must normally not be readable
by "other"; see "strict modes".

dit(bf(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.

dit(bf(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:

itemize(
  it() 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.

  it() 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.

  it() 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.

  it() 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.

  it() 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:

quote(fe80::1%link1)
quote(fe80::%link1/64)
quote(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.

dit(bf(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.

dit(bf(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
behaviour. 

dit(bf(ignore nonreadable)) This tells the rsync server 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.

dit(bf(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.

dit(bf(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:

itemize(
  it() %h for the remote host name
  it() %a for the remote IP address
  it() %l for the length of the file in bytes
  it() %p for the process id of this rsync session
  it() %o for the operation, which is either "send" or "recv"
  it() %f for the filename
  it() %P for the module path
  it() %m for the module name
  it() %t for the current date time
  it() %u for the authenticated username (or the null string)
  it() %b for the number of bytes actually transferred 
  it() %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.

dit(bf(timeout)) 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).

dit(bf(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.

dit(bf(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 verb(*.gz *.tgz *.zip *.z *.rpm *.deb *.iso *.bz2 *.tbz)

enddit()

manpagesection(AUTHENTICATION STRENGTH)

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 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 investigated.

manpagesection(RUNNING AN RSYNC SERVER OVER A REMOTE SHELL PROGRAM)

If rsync is run with both the --daemon and --rsh (-e) options, it will
spawn an rsync daemon using a remote shell connection.  Several
configuration options will not be available unless the remote user is
root (e.g. chroot, setuid/setgid, etc.).  There is no need to configure
inetd or the services map to include the rsync server port if you run an
rsync server only via a remote shell program.

ADVANCED: To run an rsync server out of a single-use ssh key, use the
"command=em(COMMAND)" syntax in the remote user's authorized_keys entry,
where command would be

quote(rsync --server --daemon .)

NOTE: rsync's argument parsing expects the trailing ".", so make sure
that it's there.  If you want to use a rsyncd.conf(5)-style
configuration file other than the default, you can added a
--config option to the em(command):

quote(rsync --server --daemon --config=em(file) .)

Note that the "--server" here is the internal option that rsync uses to
run the remote version of rsync that it communicates with, and thus you
should not be using the --server option under normal circumstances.

manpagesection(EXAMPLES)

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

verb(
[ftp]
        path = /home/ftp
        comment = ftp export area
)


A more sophisticated example would be:

uid = nobody nl()
gid = nobody nl()
use chroot = no nl()
max connections = 4 nl()
syslog facility = local5 nl()
pid file = /var/run/rsyncd.pid

verb([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 nl()
susan:herpass

manpagefiles()

/etc/rsyncd.conf or rsyncd.conf

manpageseealso()

rsync(1)

manpagediagnostics()

manpagebugs()

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
url(http://rsync.samba.org/)(http://rsync.samba.org/)

manpagesection(VERSION)
This man page is current for version 2.x of rsync.

manpagesection(CREDITS)

rsync is distributed under the GNU public license.  See the file
COPYING for details.

The primary ftp site for rsync is
url(ftp://rsync.samba.org/pub/rsync)(ftp://rsync.samba.org/pub/rsync).

A WEB site is available at
url(http://rsync.samba.org/)(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.

manpagesection(THANKS)

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

manpageauthor()

rsync was written by Andrew Tridgell and Paul Mackerras.  They may be
contacted via email at tridge@samba.org and
Paul.Mackerras@cs.anu.edu.au