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资源说明：Pure FTP server
.:. PURE-FTPD .:.
Documentation for version 1.0.48
------------------------ BLURB ------------------------
Pure-FTPd is a fast, production-quality, standard-conformant FTP server,
based upon Troll-FTPd.
The server has been designed to be secure in default configuration, it has no
known vulnerability, it is really trivial to set up and it is especially
designed for modern kernels. It was successfully ported to Linux, FreeBSD,
Dragonfly BSD, NetBSD, OpenBSD, OSX, AIX and more.
Features include chroot()ed and/or virtual chroot()ed home directories,
virtual domains, built-in 'ls', anti-warez system, configurable ports for
passive downloads, FXP protocol, bandwidth throttling, ratios,
LDAP / MySQL / PostgreSQL-based authentication, fortune files, Apache-like
log files, fast standalone mode, text / HTML / XML real-time status report,
virtual users, virtual quotas, privilege separation, TLS and more.
------------------------ WHO'S USING IT? ------------------------
Many people new to Unix are running Pure-FTPd because they find it easy to
install. But that software is also used on embedded systems and highly loaded
production servers, especially for hosting services.
For large sites with centralized user management, Pure-FTPd provides flexible
authentication schemes including SQL and LDAP backends, plus the ability to
easily write new custom handlers in any language.
------------------------ COMPILATION ------------------------
In its current form, Pure-FTPd uses some OS-specific system calls. And although
some portability work has been done in order to ease its port to other
operating systems, only Linux FreeBSD, NetBSD, OpenBSD, ISOS, MirBSD, BSDi,
DragonflyBSD, Darwin, Solaris, Tru64, Irix, AIX and HPUX are known to work,
other operating systems may need some tweaks. With Linux, any modern
distribution should be ok.
* Step 1 (optional but recommended):
Create a specific, unprivileged user and group called _pure-ftpd, without any
valid shell. Don't use this for anything else, including FTP virtual users.
groupadd _pure-ftpd
useradd -g _pure-ftpd -d /var/empty -s /etc _pure-ftpd
If having a user whose name begins with an underscore is a no-go for you,
you can also call it pure-ftpd, without the underscore.
* Step 2:
If you have Cdialog or Xdialog installed on your system, try the following
command to build and install Pure-FTPd:
make -f Makefile.gui
If you don't have Cdialog or if you prefer the conventional way, here it is:
./configure
make install-strip
Et voila! The software is now installed in /usr/local/sbin/pure-ftpd
* Step 3:
To launch the server, just type the following command:
/usr/local/sbin/pure-ftpd &
If you installed a binary package (RPM, SLP, Debian), maybe use the
following command instead:
/usr/sbin/pure-ftpd &
Your server is ready. Just type 'ftp localhost' to test it. If you want to
automatically run the server when the system boots, add the previous command
to /etc/rc.d/rc.local or /etc/rc.d/boot.local . Don't forget the '&' sign.
Note:
To deinstall Pure-FTPd (no, do you really want to do this?), use:
./configure
make uninstall
------------------------ ADVANCED COMPILATION ------------------------
The "./configure" script accepts some arguments you might want to add before
the compilation:
/--------------------
"--with-" switches
--------------------/
--with-altlog: in addition to the syslog output, support logging into a
specific file, in an alternative format. Currently, the CLF, Stats, W3C and
xferlog formats are implemented.
CLF (common log format) is the basic format produced by Apache, WebFS, Roxen
and most web servers. These log files only record file transfers and they can
feed web statistic software (Analog, Webalizer, etc.) to analyze the load of
your FTP server. The Stats format is a special output format, designed for log
file analysis software. The W3C format is a standard format parsed by most
commercial log analyzers (all analyzers with support for IIS should deal with
it) . Xferlog is the traditional format created by wu-ftpd. Check the -O
option later in this documentation for additional info.
--with-brokenrealpath: some Solaris versions have a broken realpath()
implementation. If altlog and/or pure-uploadscript doesn't seem to work
properly on your system, try to recompile with this switch.
--with-tls: enable TLS support. Read README.TLS for more about this feature.
--with-certfile=: the file with the TLS certificate (see README.TLS). The
default is /etc/ssl/private/pure-ftpd.pem .
--with-cookie: display a fortune or a customized banner when a user logs
in (see the '-F' option) .
--with-diraliases: support directory aliases ("shortcuts" for the "cd"
command) . Please read the appropriate section about this (further in this
manual) .
--with-everything: build a big server with almost all features turned on:
altlog, cookies, throttling, ratios, ftpwho, upload script, virtual users
(puredb), quotas, virtual hosts, directory aliases, external authentication,
Bonjour and privilege separation.
--with-extauth: compiles support for external authentication modules. Please
read README.Authentication-Modules and the pure-authd(8) man page before
enabling this feature. Most users don't need it.
--with-ftpwho: support for the 'pure-ftpwho' command. Enabling this feature
needs some extra memory. Better use it when the server is run in standalone
mode. It can be way slower in inetd mode.
--with-language=english
--with-language=albanian
--with-language=german
--with-language=romanian
--with-language=french
--with-language=polish
--with-language=spanish
--with-language=danish
--with-language=italian
--with-language=brazilian-portuguese
--with-language=slovak
--with-language=dutch
--with-language=korean
--with-language=swedish
--with-language=norwegian
--with-language=russian
--with-language=traditional-chinese
--with-language=simplified-chinese
--with-language=hungarian
--with-language=catalan
--with-language=czech: change the language of server messages.
Default is english. If you want to contribute a translation, please
translate the 'src/messages_en.h' file and send it to .
--with-ldap: use the native LDAP directory support. When this option is
enabled, system accounts can be bypassed. You need OpenLDAP to use that
feature. If OpenLDAP is installed in a custom location, you can use the
--with-ldap= syntax. See the README.LDAP file for more info about
LDAP and Pure-FTPd.
--with-minimal: to efficiently use features of modern FTP clients, Pure-FTPd
implements the basics of the FTP protocol, with many extensions (SITE IDLE,
SITE CHMOD, MLSD, ...) . Using the --with-minimal directive, these extensions
won't be compiled in. Also, there will be no standalone server, no lookup for
user/group names, no humor and no ASCII support. But the executable file size
will be smaller than in a default installation. You need at least GCC 3.3 to
compile with this option. Regular expressions are compiled in. If you still
want to reduce the size, use --without-globbing in conjunction with
--with-minimal. If you are building an embedded system, use this. In all other
cases, to avoid complaints from customers (especially with Windows clients),
forget this.
--with-mysql: use the native MySQL support for users database. When this
option is enabled, system accounts can be bypassed. MySQL client libraries
should be installed to use that feature. If MySQL is installed in a custom
location, you can use the --with-mysql= syntax. See the
README.MySQL file for more info about MySQL and Pure-FTPd.
--with-nonroot: set up a server that doesn't need root privileges to be
started. Any regular user can run the server. It can be useful if you have a
limited shell access to a non-dedicated hosting server. But some features
will be disabled and passwords can only be checked via LDAP, SQL or PureDB.
When virtual chroot is enabled, people will be restricted to the directory
the server was started in. This is an insecure mode, designed for setting up
very temporary servers by regular (non-root) users. Port 2121 will be
listened by default in standalone mode. If you want to use the nonroot mode,
you must compile and *install* the software (./configure --prefix=... &&
make install-strip) . /sbin, /bin and /man directories will be created in
that prefix. But you must also add an /etc directory (readable and writeable
by the user pure-ftpd will run as) . You can change the anonymous FTP root
directory through an environment variable named FTP_ANON_DIR.
--with-pam: use pluggable authentication modules. Don't use this option
if your login/passwd pairs are always refused (but the real fix would be to
fix your PAM configuration). You need to create a /etc/pam.d/pure-ftpd file
to properly use the PAM authentication. The 'pam' directory contains an
example of such a file.
--with-paranoidmsg: favor paranoid messages over sysadmin-friendly
messages. When this option is enabled, login failures will show the same
message to the user, regardless of the source of the problem. Without this
option, "Authentication failure" is displayed when this is a password
problem and "Sorry, I can't trust you" is displayed when the user has been
banned by the sysadmin.
--with-peruserlimits: enable per-user concurrency limits. Avoid this
on very loaded servers.
--with-pgsql: use the native Postgres support for users database. When this
option is enabled, system accounts can be bypassed. Postgres client libraries
should be installed to use that feature. If Postgres is installed in a custom
location, you can use the --with-pgsql= syntax. See the
README.PGSQL file for more info about Postgres and Pure-FTPd.
--with-probe-random-dev: Pure-FTPd uses /dev/urandom or /dev/random devices
to provide hardly-predicable random numbers. Presence of these devices are
usually probed at compile-time. If you want to compile a binary package on
a host, then run it on another host, this option will enable the probe at
run-time. This is useless on Linux and BSD systems, but it can be needed on
Solaris and QNX.
--with-puredb: support virtual users, ie. a local users database,
independent of your system accounts. Please read the README.Virtual-Users
file for more info about virtual users.
--with-quotas: enable virtual quotas. With virtual quotas, you can restrict
the maximal number of files a user can store in his account. You can also
of course restrict the total size. See the "quotas" section later in this
document.
--with-ratios: support upload/download ratios, to please w4r3z fr34k2.
--with-sysquotas: support system quotas (not Pure-FTPd's virtual quotas) .
--with-throttling: support bandwidth throttling (see below).
--with-uploadscript: since 0.98, Pure-FTPd has a nice feature regarding
uploads. Any external program or script can be automatically called after a
successful upload. It needs another program installed by the Pure-FTPd
package, called 'pure-uploadscript'. Check the man page for more info about
this.
--with-virtualchroot: usually, when a user is chrooted (-A and -a
options), it's impossible to go out of his home directory. Enabling that
feature makes it possible: symbolic links are always followed, even if they
are pointing to directories not located in the user's home directory. This
is very useful for having shared directories (for instance, have a symbolic
link to /var/incoming in every home directory) .
This feature isn't enabled by default.
--with-virtualhosts: support virtual hosting. It means that you can have
different anonymouns FTP areas for each IP address. If your server has only
one IP address, you don't need that feature. But if you have multiple IP
addresses and if you want a client that connects to IP xxx to get
the content of /etc/pure-ftpd/xxx/ instead of ~ftp/ , enable this option.
And read the the "VIRTUAL SERVERS" section at the end of this file.
--with-welcomemsg: read 'welcome.msg' files for compatibility with some
other FTP servers. This is a security flaw (anonymous users may upload
'welcome.msg' files to add random banners) . Pure-ftpd uses '.banner' files
by default.
--with-boring: display boring "professionnal-looking" messages.
--with-bonjour: enable Bonjour support on MacOS X (see the -v switch).
--with-rfc2640: enable support for charset conversion. It adds a dependency
over the iconv library and it requires a little more CPU time. See the -8
and -9 switches.
--with-implicittls: build a FTPS server (TLS is implicitly enabled).
The protocol is incompatible with FTP and listens to another port by default
(port 990, ftps). Never enable this option unless you know what you're doing.
/-----------------------
"--without-" switches
-----------------------/
--without-privsep: disable privilege separation (see notes about this later),
not recommended.
--without-ascii: does not support 7-bits transfers (ASCII) . If you have
customers using Windows clients to send scripts and HTML files, don't use
this option or they will yell at you.
--without-capabilities: if the capabilities library (libcap) is found,
Pure-FTPd will try to use it in order to enhance security. This option
overrides the test to ignore the library. Try this if capabilities don't
work properly on your system. libcap can be downloaded from
ftp://ftp.kernel.org/pub/linux/libs/security/linux-privs/ .
--without-globbing: don't include the globbing code. It reduces the memory
footprint but regular expressions won't work any more (things like 'ls
*.rpm') . Most people shouldn't use --without-globbing. Globbing is a nice
feature.
--without-humor: if you find what this option does without peeking at the
source code, you're a lucky guy!
--without-inetd: if you will always be running Pure-FTPd in standalone-mode,
enabling this flag can save a few code bytes. Don't enable --without-inetd
and --without-standalone, because it's impossible to run a server without
one of them. These options aren't enabled on binary distributions of
Pure-FTPd, so that both inetd-like and standalone mode are supported.
--without-iplogging: don't log any IP address to protect confidentiality,
especially for political servers.
--without-nonalnum: paranoid file name checking: only allow basic
alphanumeric characters. Never enable this switch blindly, or your customers
will complain.
--without-unicode: disallow non-latin characters. Recommended if you don't
have special characters in file names.
--without-sendfile: on Linux, Solaris, HPUX and FreeBSD kernels, Pure-FTPd
tries to reduce the CPU/memory usage by using a special system call (sendfile)
. It works very well with most filesystems. However, this optimization is not
implemented for all filesystems in current kernels. Users reported that
downloading files with Pure-FTPd failed with SMBFS (Samba) on FreeBSD and
TmpFS and NTFS on Linux (the error reported by the server is "broken pipe" or
"Error during write to data connection") . If you are planning to serve files
from these filesystems, you have to use the --without-sendfile switch to
enable a workaround. It was also reported that PA-Risc Linux systems need this
flag.
--without-shadow: ignore the shadow passwords, even though they are
auto-detected. Usually a bad idea, unless you use PAM, LDAP or SQL.
Pure-FTPd support expiration dates of shadow passwords (both for accounts
and passwords) .
--without-standalone: the FTP server can normally run in standalone-mode
(without any super-server) . If you don't need that feature and if you want
to save few code bytes, add this option. A super-server such as xinetd
or tcpserver will be mandatory to run the service. But the standalone mode is
the recommended mode of operation.
--without-usernames: never outputs user and group names in directory
listings, only UIDs and GIDs. It improves security and performances, but
some people find this not user-friendly.
/--------------
Other notes
--------------/
Other traditional autoconf options are of course recognised, in particular:
- "--prefix=" to change the installation prefix, that defaults to "/usr/local/"
- "--sysconfdir=" to change the configuration files directory (defaults to
"/etc" unless you specified a prefix with --prefix)
- "--localstatedir=" to change the runtime files directory (defaults to
"/var" even if you specified a prefix with --prefix)
FYI, the binary RPM packages of Pure-FTPd are configured with the following
command line:
./configure --with-everything --with-paranoidmsg --without-capabilities \
--with-virtualchroot
RPM packages are also compiled with --without-pam to enhance their
portability.
------------------------ STANDALONE INSTALLATION ------------------------
This is the recommended way to start the server.
Unless you compiled the server with "--without-standalone", running the
server is as easy as typing:
/usr/local/sbin/pure-ftpd &
In the following examples, we will assume that the 'pure-ftpd' file is
located in /usr/local/sbin. This is the default if you compiled the server
from the source code tarball. But as I said earlier in this document, if
you installed a binary package (RPM, SLP, DEB, TGZ), the server maybe
installed in /usr/sbin/. So just replace '/usr/local/sbin/pure-ftpd' with
'/usr/sbin/pure-ftpd'.
When the previous command is run, the server will listen for incoming
connections on every interface, all IP addresses and the standard FTP port
(21) . If your system has IPv6 addresses, they should work as well.
Now, if you want to listen for an incoming connection on a non-standard port,
just append '-S' and the port number:
/usr/local/sbin/pure-ftpd -S 42
Service names are also allowed ('-S smtp' and the daemon will be accepting
connections on the SMTP port (25) . Very uncommon, but we should please
everybody anyway, even disturbed minds) .
Now, what if your system has many IP addresses and you want the FTP server
to be reachable on only one of these addresses, let's say 192.168.0.42?
Just use the following command line:
/usr/local/sbin/pure-ftpd -S 192.168.0.42,
The final comma is important, don't forget it. Actually, it's a shorthand for:
/usr/local/sbin/pure-ftpd -S 192.168.0.42,21
If you prefer host names over IP addresses, it's your choice:
/usr/local/sbin/pure-ftpd -S ftp.example.com,21
IPv6 addresses are of course supported.
With previous command lines, the server will run in the default
configuration. Anonymous FTP logins will be allowed if there's a system
account called 'ftp' and every user of your system will be able to access
the FTP server using their regular login/password pair.
If you need to tweak that default configuration, other command-lines options
can be added. For instance:
/usr/local/sbin/pure-ftpd -c 50 &
or
/usr/local/sbin/pure-ftpd -S ftp.example.com,21 -c 50 &
And only 50 simultaneous connections will be allowed. To discover what
options are available please jump to the 'OPTIONS' chapter below. If the
server runs perfectly for you in standalone mode, you don't need to read the
following chapter about super-servers. But read the options. '-m' and '-C'
are recommended. '-D' is also a good choice if you (or your customers) use
broken clients. Please read on.
When you run 'ps auxw|grep pure-ftpd', the result looks like this:
root 15211 0.1 0.3 1276 452 ? S 13:53 0:00 pure-ftpd [SERVER]
root 15212 0.1 0.5 1340 672 ? S 13:54 0:00 pure-ftpd [IDLE]
root 15214 0.0 0.5 1340 672 ? S 13:56 0:00 pure-ftpd [DOWNLOADING]
[SERVER] is the main server. If you kill this process, the server will exit
after the next connection.
[IDLE] shows a client with no transfer activity.
[DOWNLOADING] shows a client downloading a file.
[UPLOADING] show a client uploading a file.
For easy scripting, the file '/var/run/pure-ftpd.pid' is created and it
always contains the PID of the main server process.
If you want to stop the server, you can just kill the processes:
pkill -x pure-ftpd
Of course, don't use -9 unless the server is completely stuck. -9 doesn't
let processes any chance to clean things up and should never be used except
where there's absolutely nothing else to do.
------------------------ SUPER-SERVER INSTALLATION ------------------------
Pure-FTPd can also run with the help of a super-server, like telnet, wu-ftp,
finger or Qmail. This is not recommended. If this is an option, start it in
standalone mode instead. Using a super-server is usually slower than the
standalone mode. But if you love tcpwrappers or built-in filtering abilities
of your super-server, Pure-FTPd can cope with them.
Unix has tons of super-servers: Inetd (the most common one), TCPserver,
G2S, Xinetd, Rlinetd, ... Only the first three will be covered here, but
integration with other super-servers should be painless.
**** Usage with Inetd ****
Important: if security matters for you, forget inetd. In the default
configuration, inetd will stop a service after a high rate of connections to
the same port. This creates an easy denial-of-service. Also, inetd doesn't
have any concurrency limit. Bad guys can fill up your memory and your
descriptor tables even if you are restricting the number of connections in
pure-ftpd. Better use a modern replacement for inetd, or run pure-ftpd in
standalone mode.
1) Check that inetd is up:
ps auxw | grep inetd
root 3699 0.0 0.3 1072 492 ? S 15:47 0:00 inetd
2) Edit /etc/inetd.conf and look for a line like:
ftp stream tcp nowait root /usr/sbin/tcpd in.ftpd
The line may also end with "proftpd" or "wuftpd", but it should start with
"ftp stream tcp".
3) Replace that line with the following one:
ftp stream tcp nowait root /usr/sbin/tcpd /usr/local/sbin/pure-ftpd
If /usr/sbin/tcpd is missing on your system, try the following line instead:
ftp stream tcp nowait root /usr/local/sbin/pure-ftpd pure-ftpd
4) Restart the inetd daemon:
pkill -x -s HUP inetd
If 'pkill' is missing on your system, try this:
kill -HUP $(cat /var/run/inetd.pid)
**** Usage with Xinetd ****
Add the following entry to the /etc/xinetd.conf file:
service ftp
{
socket_type = stream
server = /usr/local/sbin/pure-ftpd
protocol = tcp
user = root
wait = no
disable = no
}
On Redhat systems, you can also put this in a /etc/xinetd.d/pure-ftpd file.
Then, restart the server:
pkill -x -s USR2 xinetd
**** Usage with TCPserver ****
TCPServer is part of the ucspi-tcp package by Dan Bernstein.
The simplest way of running Pure-FTPd with TCPserver is the following command:
tcpserver -DHRl0 0 21 /usr/local/bin/pure-ftpd &
You can add that line to your system local startup scripts
(usually /etc/rc.d/boot.local or /etc/rc.d/rc.local) . If it doesn't work,
replace 'tcpserver' with its full path (eg. '/usr/local/bin/tcpserver') .
------------------------ OPTIONS ------------------------
The previous steps should be enough to get a running FTP server. But you can
add some command-line arguments to change its behavior. These arguments have
to be added after the pure-ftpd path in your super-server configuration.
For instance, you want to add the '-s' and '-a 42' flags. Here are what the
configuration lines will look like in your super-server:
- Inetd:
ftp stream tcp nowait root /usr/sbin/tcpd /usr/local/sbin/pure-ftpd -s -a42
or
ftp stream tcp nowait root /usr/local/sbin/pure-ftpd pure-ftpd -s -a42
If you use Inetd, don't put space between options and arguments. e.g. use
-a42 instead of -a 42 . Inetd has trouble dealing with a lot of options and
with characters like ':' .
- Xinetd:
service ftp
{
socket_type = stream
server = /usr/local/sbin/pure-ftpd
server_args = -s -a 42
protocol = tcp
user = root
wait = no
disable = no
}
- TCPserver:
tcpserver -DHRl0 0 21 /usr/local/bin/pure-ftpd -s -a 42 &
- G2S:
{
SERVICE ftp
DESCRIPTION "Pure-FTPd"
RUN /usr/local/sbin/pure-ftpd -s -a 42
}
Users need a shell listed in /etc/shells to get restricted or unrestricted
FTP access. Alternatively, you can give them "ftp" as a shell. Users with a
"ftp" shell will be able to login through FTP only: no telnet, no SSH. And
there's no need (and you shouldn't do so) for an "ftp" entry in /etc/shells.
Here are the recognized switches:
- '-0': when a file is uploaded and there is already a previous version of the
file with the same name, the old file will neither get removed nor truncated.
Upload will take place in a temporary file and once the upload is complete,
the switch to the new version will be atomic. For instance, when a large PHP
script is being uploaded, the web server will still serve the old version and
immediately switch to the new one as soon as the full file will have been
transferred.
- '-1': log the PID of each session in syslog output.
- '-2 ': when using TLS, set the path to the certificate file.
- '-4': only listen to IPv4 connections.
- '-6': don't listen to IPv4, only listen to IPv6.
- '-a ': authenticated users will be granted access to their home
directory and nothing else (chroot) . This is especially useful for users
without shell access, for instance, WWW-hosting services shared by several
customers. Only member of group number will have unrestricted access
to the whole filesystem. So add a "staff", "admin" or "ftpadmin" group and
put your trusted users in. is a NUMERIC group number, not a group name.
This feature is mainly designed for system users, not for virtual ones.
Note: 'root' (uid 0) always has full filesystem access.
If you want to chroot() everyone, but root, use the following flag:
- '-A': chroot() everyone, but root. There's no such thing as a trusted
group. '-A' and '-a ' are mutually exclusive.
- '-b': Ignore parts of RFC standards in order to deal with some totally
broken FTP clients, or broken firewalls/NAT boxes. Also, non-dangling
symbolic links are shown as real files/directories.
- '-B': Have the standalone server start in background (daemonization).
- '-c ': Allow a maximum of clients to be connected. For
instance '-c 42' will limit access to simultaneous 42 clients. There is a
50 client limit by default.
- '-C ': Limit the number of simultaneous connections
coming from the same IP address. This is yet another very effective way to
prevent stupid denial of services and bandwidth starvation by a single user.
It works only when the server is launched in standalone mode (if you use a
super-server, it is supposed to do that) . If the server is launched with
'-C 2', it doesn't mean that the total number of connections is limited to 2.
But the same client, coming from the same machine (or at least the same IP),
can't have more than two simultaneous connections. This feature needs some
memory to track IP addresses, but it's recommended to use it.
- '-d': Send various debugging messages to the syslog. Don't use this
unless you really want to debug Pure-FTPd. Passwords aren't logged.
Duplicate '-d' to log responses, too.
- '-D': List files beginning with a dot ('.') even when the client doesn't
append the '-a' option to the list command. A workaround for badly
configured FTP clients. If you are a purist, don't enable this. If you
provide hosting services and if you have lousy customers, enable this.
- '-e': Only allow anonymous users. Use this on a public FTP site with no
remote FTP access to real accounts.
- '-E': Only allow authenticated users. Anonymous logins are prohibited.
- '-f ': Use that facility for syslog logging. It defaults to
'ftp' (or 'local2' if you got an obsolete libc without that facility).
Logging can be disabled with '-f none' .
- '-F ': Display a fortune cookie on login. The sentence is
a random extract from the text file . This text file should be
formatted like standard "fortune" files (fortunes are separated by a '%'
sign on a single line) . Pure-FTPd has to be compiled with support for
cookies (--with-cookie). If you just want a simple banner displayed before
the login prompt, add the name of any text file here.
- '-g ': Change the location of the pid file when the server is
run in standalone mode. The default is /var/run/pure-ftpd.pid .
- '-G': Disallow renaming.
- '-H': By default, fully-qualified host names are logged. To achieve this,
DNS lookups are mandatory. The '-H' flag avoids host names resolution.
("213.41.14.252" will be logged instead of "www.toolinux.com") . It can
significantly speed up connections and reduce bandwidth usage on busy
servers. Use it especially on public FTP sites. Also, please note that
without -H, host names are informative but shouldn't be trusted: no reverse
mapping check is done to save DNS queries.
- '-i': Disallow upload for anonymous users, whatever directory permissions
are. This option is especially useful for virtual hosting, to avoid your
users creating warez sites in their account.
- '-I ': Change the maximum idle time. The timeout is in minutes
and defaults to 15 minutes. Modern FTP clients are trying to fool timeouts
by sending fake commands at regular interval. We disconnect these clients
when they are idle for twice (because they are active anyway) the normal
timeout.
- '-j': If the home directory of a user doesn't exist, automatically create
it. The newly created home directory belongs to the user and permissions are
set according to the current directory mask. Only the home directory can be
created (so /home/john/./public_html won't work, but /home/john will) . To
avoid local attacks, the parent directory should never belong to an untrusted
user. Also note that you must trust whoever manages the users databases,
because with that feature, he'll be able to create/chown directories anywhere
on the server's filesystem.
- '-J ': Sets the list of ciphers that will be accepted for
TLS connections.
- '-k ': Don't allow uploads if the partition is more than
% full. For instance, "-k 95" will ensure your disks will never
get filled more than 95% by FTP. No need for the "percent" sign after the
number.
- '-K': Allow users to resume and upload files, but *NOT* to delete or rename
them. Directories can be removed, but only if they are empty. However,
overwriting existing files is still allowed (to support upload resume) . If
you want to disable this too, add -r (--autorename) .
- '-l ' or '-l :': Adds a new
rule to the authentication chain. Please read the "Authentication" section,
later in this README file. It's an important section.
- '-L :': To avoid stupid denial-of-service attacks
(or just CPU hogs), Pure-FTPd never displays more than 10000 files in response
to an 'ls' command. Also, a recursive 'ls' (-R) never goes further than 5
subdirectories. You can increase/decrease those limits with the '-L' option.
- '-m ': Don't allow anonymous download if the load is above . A very efficient way to prevent overloading your server. Upload is
still allowed, though.
- '-M': Allow anonymous users to create directories.
- '-n :': If the server has been compiled with support
for virtual quotas, enforce these quota settings for all users (except
members of the 'trusted' group) . is in Megabytes. See the
"virtual quotas" section later in this document.
- '-N': NAT mode. Force ACTIVE mode. If your FTP server is behind a NAT box
that doesn't support applicative FTP proxying, or if you use port
redirection without a transparent FTP proxy, use this. Well... the previous
sentence isn't very clear. Okay: if your network looks like this:
(FTP server)-------(NAT/masquerading gateway/router)------(Internet)
and if you want people coming from the internet to have access to your FTP
server, please try without this option first. If Netscape clients can
connect without any problem, your NAT gateway rulez. If Netscape doesn't
display directory listings, your NAT gateway sucks. Use '-N' as a workaround.
- '-o': Write all uploaded files to '/var/run/pure-ftpd.upload.pipe' so
that the 'pure-uploadscript' program can run. Don't enable that option if
you don't actually use 'pure-uploadscript' otherwise pure-ftpd will hang
waiting for pure-uploadscript to start.
- '-O :': Record all file transfers into a specific log
file, in an alternative format. Currently, four formats are supported: CLF
(Apache-like), Stats, W3C and xferlog.
If you add '-O clf:/var/log/pureftpd.log' to your starting options,
Pure-FTPd will log transfers in /var/log/pureftpd.log in a format similar to
the Apache web server in default configuration.
If you use '-O stats:/var/log/pureftpd.log' to your starting options,
Pure-FTPd will create log files in a special format, designed for statistical
reports. The Stats format is compact, more efficient and more accurate that
CLF and the old broken "xferlog" format.
The Stats format is:
is a GMT timestamp (time()) and identifies the current
session. is unquoted, but it's always the last element of a log line.
"U" means "Upload" and "D" means "Download".
Warning: the session id is only designed for statistics purposes. While it's
always an unique string in the real world, it's theoretically possible to have
it non unique in very rare conditions. So don't rely on it for critical
missions.
A command called "pure-statsdecode" can be used to convert timestamps into
human-readable dates.
The W3C format is enabled with '-O w3c:/var/log/pureftpd.log' .
For security purposes, the path must be absolute (eg. /var/log/pureftpd.log
, not ../log/pureftpd.log) . If this log file is stored on a NFS volume, don't
forget to start the lock manager (often called "lockd" or "rpc.lockd").
- '-p :': Use only ports in the range
to inclusive for passive-mode downloads. This is especially
useful if the server is behind a firewall without FTP connection tracking.
Use high ports (40000-50000 for instance), where no regular server should be
listening.
- '-P ': Force the specified IP address in reply to
a PASV/EPSV command. If the server is behind a masquerading (NAT) box that
doesn't properly handle stateful FTP masquerading, put the ip address of
that box here. If you have a dynamic IP address, you can put the public host
name of your gateway, that will be resolved every time a new client will
connect.
- '-q :': Enable ratios for anonymous users.
- '-Q :': Enable ratios for everybody
(anonymous and non-anonymous). Members of the root (0, something called
'wheel') have no ratio.
- '-r': Never overwrite existing files. Uploading a file whose name
already exists cause an automatic rename. Files are called xyz, xyz.1, xyz.2,
xyz.3, etc.
Tip: if you compile with 'make AUTORENAME_REVERSE_ORDER=1' , the naming
convention will be reversed. Files will be called xyz, 1.xyz, 2.xyz, 3.xyz,
etc.
- '-R': Disallow users (even non-anonymous ones) usage of the CHMOD
command. On hosting services, it may prevent newbies from making mistakes,
like setting bad permissions on their home directory. Only root can use
CHMOD when -R is enabled.
- '-s': The "waReZ protection". Don't allow anonymous users to download
files owned by "ftp" (generally, files uploaded by other anonymous users) .
So that uploads have to be validated by a system administrator (chown to
another user) before being available for download.
- '-S [,|,] [|]'. This option is
only effective when the server is launched as a standalone server.
Connections are accepted on the specified IP and port. IPv4 and IPv6 are
supported. Numeric and fully-qualified host names are accepted. A service
name (see /etc/services) can be used instead of a numeric port number.
- '-T ' and '-t ': Enable bandwidth limitation (see
below) . is specified in kilobytes/seconds. To set up separate
upload/download bandwidth, the []:[] syntax is supported.
- '-u ': Don't allow uids below to log in. '-u 1' denies access
to root (safe), '-u 100' denies access to virtual accounts on most Linux
distros.
- '-U :': Change the file creation mask.
The default is 133:022. If you want a new file uploaded by a user to only be
readable by that user, use '-U 177:077'. If you want uploaded files to be
executable, use 022:022 (files will be readable -but not writable- by other
users) or 077:077 (files will only be executable and readable by their
owner) . Please note that Pure-FTPd support the SITE CHMOD extension, so a
user can change the permissions of his own files.
- '-V ': Allow non-anonymous FTP access only on this specific
local IP address. All other IP addresses are only anonymous. With that
option, you can have routed IPs for public access and a local IP (like
10.x.x.x) for administration. You can also have a routable trusted IP
protected by firewall rules and only that IP can be used to login as a
non-anonymous user.
- '-v ': Set the service name for Apple's Bonjour. Only available on
MacOS X when Bonjour support is compiled in.
- '-w': Support the FXP protocol only for authenticated users. FXP works
with IPv4 and IPv6 addresses.
- '-W': Support the FXP protocol. FXP allows transfers between two remote
servers without any file data going to the client asking for the transfer.
However:
****************************************************************************
*FXP IS AN INSECURE PROTOCOL* (third-party hosts can steal the current
connection) . In Pure-FTPd, specific precautions have been taken to reduce
FXP insertion attacks. But if your FTP server serves private data:
NEVER ALLOW FXP ACCESS TO UNTRUSTED HOSTS. YOU CAN PLAY WITH IT ON AN
INTERNAL SERVER, BUT _DON'T_ GIVE FXP ACCESS TO ANONYMOUS INTERNET USERS.
****************************************************************************
It's why FXP is disabled by default on Pure-FTPd unless you
explicitly enable it with '-W' or '-w'.
- '-x': In normal operation mode, authenticated users can read/write files
beginning with a dot ('.') . Anonymous users can't, for security reasons
(like changing banners or a forgotten .rhosts) . When '-x' is used,
authenticated users can download dot-files, but not overwrite/create them,
even if they own them. That way, you can prevent hosted users from messing
.qmail files. If you want to give user access to a special dot-file, create a
symbolic link to the dot-file with a file name that has no dot in it and the
client will be able to retrieve the file through that link.
- '-X': This flag is identical to the previous one (writing dot-files is
prohibited), but in addition, users can't even *read* files and directories
beginning with a dot (like "cd .ssh") .
****************************************************************************
When used in conjunction with "-a", members of the trusted group can bypass
'-x'/'-X' restrictions.
****************************************************************************
- '-y :': This option only
works if the server has been compiled with --with-peruserlimits. It
restricts the number of concurrent sessions the same user can have.
A null value ('0') means 'unlimited'.
Here's a concrete example:
/usr/local/sbin/pure-ftpd -y 3:20 -c 15 -C 5 -B
Here, we allow:
* A max total of 15 sessions.
* 5 connections max coming from the same IP address.
* 3 connections max with the same user name.
* 20 anonymous users max.
With such a setup, a single user can't easily fill all slots.
- '-Y 0': Disable the TLS encryption layer (default).
'-Y 1': Accept both standard and encrypted sessions.
'-Y 2': Refuse connections that aren't using TLS security mechanisms,
including anonymous sessions. The server must have been compiled with
--with-tls and a valid certificate must be in place to get this feature.
See the README.TLS file for more info about TLS.
'-Y 3': Cleartext sessions are refused and only TLS compatible
clients are accepted. Clear data connections are also refused, so private
data connections are enforced.
- '-z': Allow anonymous users to read files and directories starting with a
dot ('.') .
- '-Z': Try to protect customers against common mistakes to avoid your
technical support being busy with stupid issues. Right now, the '-Z' switch
prevents your users against making bad 'chmod' commands, that would deny
access to files/directories to themselves. The switch may turn on other
features in the future. If you are a hosting provider, turn this on.
If you prefer long options (GNU-style) over standard ones, the following
aliases are available. You can get this list at any time by typing
'pure-ftpd --help' .
--(switches sorted by ##standard switches## lexical order)--
-0 --notruncate
-1 --logpid
-4 --ipv4only
-6 --ipv6only
-8 --fscharset
-9 --clientcharset
-a --trustedgid
-A --chrooteveryone
-b --brokenclientscompatibility
-B --daemonize
-c --maxclientsnumber
-C --maxclientsperip
-d --verboselog
-D --displaydotfiles
-e --anonymousonly
-E --noanonymous
-f --syslogfacility
-F --fortunesfile
-g --pidfile
-G --norename
-h --help
-H --dontresolve
-i --anonymouscantupload
-I --maxidletime
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