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
immediatly switch to the new one as soon as the full file will have been
transfered.
- '-1': log the PID of each session in syslog output.
- '-4': only listen to IPv4 connections.
- '-6': don't listen to IPv4, only listen to IPv6.
- '-a <gid>': 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 <gid> will have unrestricted access
to the whole filesystem. So add a "staff", "admin" or "ftpadmin" group and
put your trusted users in. <gid> 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 <gid>' 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
symoblic links are shown as real files/directories.
- '-B': Have the standalone server start in background (daemonization).
- '-c <number of clients>': 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 <max connection per ip>': Limit the number of simultanous 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 <facility>': 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 <fortune file>': Display a fortune cookie on login. The sentence is
a random extract from the text file <fortune 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 <pid file>': 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 <timeout>': 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 <ciphers>': Sets the list of ciphers that will be accepted for
SSL/TLS connections.
For example: -J HIGH:MEDIUM:+TLSv1:!SSLv2:+SSLv3
Prefixing the list with -S: totally disables SSLv3.
- '-k <percentage>': Don't allow uploads if the partition is more than
<percentage>% 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 <authentication>' or '-l <authentication>:<config file>': Adds a new
rule to the authentication chain. Please read the "Authentication" section,
later in this README file. It's an important section.
- '-L <max files>:<max depth>': 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 <cpu load>': Don't allow anonymous download if the load is above <cpu
load> . A very efficient way to prevent overloading your server. Upload is
still allowed, though.
- '-M': Allow anonymous users to create directories.
- '-n <max files>:<max size>': If the server has been compiled with support
for virtual quotas, enforce these quota settings for all users (except
members of the 'trusted' group) . <max size> 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 <format>:<log file>': 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:
<date> <session id> <user> <ip> <U or D> <size> <duration> <file>
<date> is a GMT timestamp (time()) and <session id> identifies the current
session. <file> 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 <first port>:<last port>': Use only ports in the range <first port>
to <last port> 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 <ip address or host name>': Force the specified IP address in reply to
a PASV/EPSV/SPSV 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 <upload ratio>:<download ratio>': Enable ratios for anonymous users.
- '-Q <upload ratio>:<download ratio>': 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 [<ip address>,|<hostname>,] [<port>|<service name>]'. 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 <bandwidth>' and '-t <bandwidth>': Enable bandwidth limitation (see
below) . <bandwidth> is specified in kilobytes/seconds. To set up separate
upload/download bandwidth, the [<upload>]:[<download>] syntax is supported.
- '-u <uid>': Don't allow uids below <uid> to log in. '-u 1' denies access
to root (safe), '-u 100' denies access to virtual accounts on most Linux
distros.
- '-U <umask for files>:<umask for dirs>': 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 <ip address>': 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 <name>': 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
explicitely 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 <max user logins>:<max anonymous logins>': 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 SSL/TLS encryption layer (default).
'-Y 1': Accept both standard and encrypted sessions.
'-Y 2': Refuse connections that aren't using SSL/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 SSL/TLS.
'-Y 3': Cleartext sessions are refused and only SSL/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 <file>
-4 --ipv4only
-6 --ipv6only
-8 --fscharset <charset>
-9 --clientcharset <charset>
-a --trustedgid <gid>
-A --chrooteveryone
-b --brokenclientscompatibility
-B --daemonize
-c --maxclientsnumber <number>
-C --maxclientsperip <number>
-d --verboselog
-D --displaydotfiles
-e --anonymousonly
-E --noanonymous
-f --syslogfacility <facility>
-F --fortunesfile <file>
-g --pidfile <path to pid file>
-G --norename
-h --help
-H --dontresolve
-i --anonymouscantupload
-I --maxidletime <time (min)>
-j --createhomedir
-J --tlsciphersuite <ciphers>
-k --maxdiskusagepct <percentage>
-K --keepallfiles
-l --login <auth> or <auth>:<config file>
-L --limitrecursion <number:number>
-m --maxload <load>
-M --anonymouscancreatedirs
-N --natmode
-o --uploadscript
-O --altlog <format>:<log file>
-p --passiveportrange <minport:maxport>
-P --forcepassiveip <ip address>
-q --anonymousratio <upload ratio>:<download ratio>
-Q --userratio <upload ratio>:<download ratio>
-r --autorename
-R --nochmod
-s --antiwarez
-S --bind <ip address,port>
-t --anonymousbandwidth <bandwidth (KB/s)>
-T --userbandwidth <bandwidth (KB/s)> or [<up bw>]:[<down bw>]
-u --minuid <uid>
-U --umask <mask>
-v --bonjour <name>
-V --trustedip <ip address>
-w --allowuserfxp
-W --allowanonymousfxp
-x --prohibitdotfileswrite
-X --prohibitdotfilesread
-y --peruserlimits <per user max>:<max anonymous sessions>
-Y --tls <0:no TLS | 1:TLS+cleartext | 2:enforce TLS |
3: enforce encrypted data channel as well>
-z --allowdotfiles
-Z --customerproof
--(switches sorted by ##GNU-style long switches## lexical order)--
-W --allowanonymousfxp
-z --allowdotfiles
-w --allowuserfxp
-O --altlog <format>:<log file>
-t --anonymousbandwidth <bandwidth (KB/s)>
-M --anonymouscancreatedirs
-i --anonymouscantupload
-e --anonymousonly
-q --anonymousratio <upload ratio>:<download ratio>
-s --antiwarez
-r --autorename
-S --bind <ip address,port>
-b --brokenclientscompatibility
-A --chrooteveryone
-9 --clientcharset <charset>
-j --createhomedir
-Z --customerproof
-B --daemonize
-D --displaydotfiles
-H --dontresolve
-Y --tls <0:no TLS | 1:TLS+cleartext | 2:enforce TLS |
3:enforce encrypted data channel as well>
-P --forcepassiveip <ip address>
-F --fortunesfile <file>
-8 --fscharset <charset>
-h --help
-4 --ipv4only
-6 --ipv6only
-K --keepallfiles
-l --login <auth> or <auth>:<config file>
-1 --logpid <file>
-L --limitrecursion <number:number>
-c --maxclientsnumber <number>
-C --maxclientsperip <number>
-k --maxdiskusagepct <percentage>
-I --maxidletime <time (min)>
-m --maxload <load>
-u --minuid <uid>
-N --natmode
-E --noanonymous
-R --nochmod
-G --norename
-0 --notruncate
-v --bonjour <name>
-p --passiveportrange <minport:maxport>
-y --peruserlimits <per user max>:<max anonymous sessions>
-g --pidfile <path to pid file>
-X --prohibitdotfilesread
-x --prohibitdotfileswrite
-f --syslogfacility <facility>
-J --tlsciphersuite <ciphers>
-a --trustedgid <gid>
-V --trustedip <ip address>
-U --umask <mask>
-o --uploadscript
-T --userbandwidth <bandwidth (KB/s)> or [<up bw>]:[<down bw>]
-Q --userratio <upload ratio>:<download ratio>
-d --verboselog
------------------------ SETTING UP AN ANONYMOUS FTP ------------------------
If a 'ftp' user exists and its home directory is reachable, Pure-FTPd will
accept anonymous login, as 'ftp' or 'anonymous'. Files have to be located in
the home FTP directory. There's no need for 'bin', 'lib', 'etc' and 'dev'
directories, nor any external program. Don't chown the public files to
'ftp', just writable directories ('incoming') .
------------------------ DISPLAYING BANNERS ------------------------
If a '.banner' file is located in the 'ftp' user home directory (or in the
root directory of a virtual server, see below), it will be printed when the
client logs in. Put a nice ASCII-art logo with your name in that file.
This file shouldn't be larger than 4000 bytes, or it won't be displayed.
In each directory, you may also have a '.message' file. Its content will be
printed when a client enters the directory. Such a file can contain important
information ("Don't download version 1.7, it's broken!") .
------------------------ DISPLAYING A COOKIE ------------------------
A funny random message can be displayed in the initial login banner. The
random cookies are extracted from a text file, in the standard "fortune"
format. If you installed the "fortune" package, you should have a directory
(usually /usr/share/fortune) with binary files (xxxx.dat) and text files
(without the .dat extension) . To use Pure-FTPd cookies, just add the name
of a text file to the '-F' option. For instance:
/usr/local/sbin/pure-ftpd -F /usr/share/fortune/zippy
If you want to have your own fortune files, just create a text file with the
following structure.
Hello... this is the first fortune...
%
Welcome to the real world.
%
Follow the white rabbit.
%
Have fun...
Well... lotsa fun!
%
Yop is good for you.
Goddit? Fortunes are delimited by a '%' sign on a single line. But a
fortune itself can be multi-line (see the fourth example) .
For security paranoia, the text file has to be readable by everybody (chmod
644 the file if necessary), or the server will ignore it.
Of course, the fortune file can contain a single message.
------------------------ PER-USER CHROOT() RULES ------------------------
Apart from the "-a" flag, Pure-FTPd has another way to fine-tune chroot()
rules. Let's take an /etc/passwd entry:
mimi:x:501:100:Mimi:/home/mimi:/bin/zsh
Without any special rule, mimi will be able to log in and to retrieve any
public-readable file in the filesystem. Now, let's change a bit of its home
directory:
mimi:x:501:100:Mimi:/home/mimi/./:/bin/zsh
So what? Mimi's home directory is still the same and common applications
shouldn't notice any difference. But Pure-FTPd understands "chroot() until
/./". So when mimi next carries out a FTP log in, only the /home/mimi
directory will be reachable, not the whole filesystem. If you don't like the
"-a" and its trusted gid thing, this is a good way to only chroot() some
users. Another trick is to add something after "/./":
mimi:x:501:100:Mimi:/home/mimi/./public_html:/bin/zsh
When Mimi will log in, two things will happen:
- chroot("/home/mimi") so that Mimi can't see anything but her home directory.
- chdir("public_html") so the session will start in the public_html
directory. "cd .." is still allowed, though.
That "url-style" handling is especially handy for FTP-only users (ie.
without shell access) .
If a user is chrooted with the /./ trick *and* belongs to the trusted group
(-a) he *will* be chrooted, but he will have no ratio and will be allowed to
access dot files.
------------------------ RATIOS ------------------------
If you want to force people to upload new files before being able to
download other files, ratios are for you. It's a very good way to get lotsa
fresh stuff on a public FTP server and a must for warez traders. I don't
like that kind of business, but well... Pure-FTPd has to be designed to
please everybody.
To enable ratios, just use the '-q' option, followed by the upload:download
ratio:
-q 2:5
...means that an anonymous user has to upload at least 2 Mb of goodies to be
able to download 5 Mb.
If ratios should apply to everyone (anon and non-anon), use the '-Q' option
the same way.
Note: 'root' never has ratios. Neither have users of the trusted group when
'-Q' in used with the '-a' or '-A' option.
------------------------ BANDWIDTH THROTTLING ------------------------
Pure-FTPd has an interesting built-in feature: simple bandwidth throttling.
* You want to limit FTP throughput so that uploading and downloading files
through that protocol can't fill up your network bandwidth.
-> Compile Pure-FTPd with --with-throttling
-> Run it with the '-T' flag, followed by a number. That number is the
maximum bandwidth a user can use in a session, in kilobytes/seconds.
* You want to allow less bandwidth to your anonymous users than your
authenticated ones. So that during a bandwidth starvation, real users can
still upload/download properly.
-> Compile Pure-FTPd with --with-throttling
-> Run it with the '-t' flag, followed by a number.
Example:
/usr/local/sbin/pure-ftpd -t 64
And uploading/downloading files can't take more than 64 KB/sec whatever real
bandwidth you have.
* It is possible to have different bandwidth limits for uploads and for
downloads. '-t' and '-T' can indeed be followed by two numbers delimited by
a column (':') . The first number is the upload bandwidth and the next one
applies only to downloads. One of them can be left blank which means infinity.
Example 1: 256 KB/s for uploads, 64 KB/s for downloads
/usr/local/sbin/pure-ftpd -t 256:64
Example 2: 256 KB/s for uploads, no limit for downloads
/usr/local/sbin/pure-ftpd -t 256:
Example 3: no limit for uploads, 64 KB/s for downloads
/usr/local/sbin/pure-ftpd -t:64
With no column, the value applies to both, so '-t 64' is an alias for
'-t 64:64' .
* When Pure-FTPd serves a session with restricted bandwidth, it decreases
its process priority to 10. So, '-t 0' makes sense: during a CPU
starvation, authenticated sessions may be more responsible than anonymous
ones. '-T 0' is quite useless, but it also works and it will always be nice to
the server process.
* If you need advanced bandwidth management, have a look at your kernel
Q.O.S. abilities.
------------------------ VIRTUAL SERVERS ------------------------
Using Virtual servers is a convenient way of hosting several FTP sites on the same
computer. Let's say, you got two customers. The former owns the 'cgx.org'
domain name, while the latter owns the 'example.com' domain name. Both are
hosted on the same computer, but they don't want to share the same files.
ftp://ftp.cgx.org/ should show different content than ftp://ftp.example.com/
.
The FTP protocol doesn't allow name-based selection. So, if you want to host
<N> different virtual FTP servers on the same host and keep the standard port,
you need <N> different IP addresses. Yes, Sir. Or use HTTP.
Assign the needed IP adresses to your network adapter (with "ifconfig eth0:x
..." or "ip addr add dev eth0 a.b.c.d").
Now, create a /etc/pure-ftpd directory if it doesn't exist:
mkdir /etc/pure-ftpd
To add a virtual FTP server, you only need to create a symbolic link in
/etc/pure-ftpd/ from the virtual host IP to the directory that contains the
file for that virtual host.
Example:
ln -s /home/customers/example.com/ftp /etc/pure-ftpd/216.226.17.77
ln -s /home/customers/cgx.org/ftp /etc/pure-ftpd/212.73.209.252
Done! Put the CGX files in /home/customers/cgx.org/ftp/ and the Example
files in /home/customers/example.com/ftp/ .
With that feature, every account on the server can have its own public
anonymous FTP area. If you are providing hosting services, this is a nice
feature for your customers.
* WARNING *: it also means that your customers can create "incoming"
directories with 1777 permissions. It can be nice, but it can also fill up
your disk with warez. You can stop uploads for anonymous users with the
'-i' (or --anonymouscantupload) option.
By default, all IP addresses assigned to your server can be accessed by real
or anonymous users. You can restrict this with -e (only anonymous) or -E
(only real) .
A more flexible way is to use '-V <ip address>' to define a "trusted" IP
address. When a client connects to that trusted IP, anonymous and real
logins are permitted. But on all other IP, only anonymous users are permitted.
If you are a hosting service provider and if each customer has its own IP
address, it may be a nice idea to have a trusted IP you give to all your
customers, so that they can manage the files in their account. That IP is
the same for all customers. You can easily restrict access to that IP with
firewall rules if your customers have static IP addresses.
Use '-V <trusted ip>' and link /etc/pure-ftpd/<customer ip> to
~customer/ftp . Every customer will have his own *anonymous only* FTP
server and hackers will have to find the trusted IP to get in.
------------------------ IPv6 SUPPORT ------------------------
Pure-FTPd has full IPv6 support (native IPv6 addresses and 4-in-6
addresses). But use a super-server that also understands the IPv6 protocol,
like Rlinetd or Xinetd. Recent versions of Inetd should also be ok
(unverified). IPv6 is supported everywhere: logging, configuration
switches, virtual hosts, protocol (EPSV/EPRT support), name resolution...
--------------------- LOGGING ---------------------
Log messages are sent to the syslog daemon. You can disable logging with
'-f none'.
If you want all FTP messages to be redirected to a file, say /var/log/ftp,
add this line to your /etc/syslog.conf file:
ftp.* /var/log/ftp
Then restart your syslogd daemon:
killall -HUP syslogd
You can also drop your old "syslogd" and "klogd" programs for Metalog, an
efficient alternative: http://metalog.sourceforge.net/
Names of uploaded/downloaded files are logged with paths like this:
/home/ftp//pub/bla.jpg
The double-slash ('//') is the chroot limit.
--------------------- WATCHING CURRENT SESSIONS ---------------------
Since 0.97.7, you can type 'pure-ftpwho' at any time to watch current active
sessions.
If typing 'pure-ftpwho' answers 'Command not found', you have to add
/usr/local/sbin in your PATH environment variable.
The default output looks like this:
+------+---------+-------+------+-------------------------------------------+
| PID | Login |For/Spd| What | File/IP |
+------+---------+-------+------+-------------------------------------------+
| 2239 | jedi | 00:17 | D/L | XFree86-clients-4.0.3.tar.gz |
| '' | '' | 41K/s| 33% | -> nestea.funboard.de |
+------+---------+-------+------+-------------------------------------------+
| 2385 | ftp | 00:02 | IDLE | |
| '' | '' | | | -> gw2.crn.kjop.co.uk |
+------+---------+-------+------+-------------------------------------------+
'D/L' means that the client is downloading and 'U/L' means he's uploading
some file whose name is shown in the next column. '33%' is the real-time
completion of the current operation. '41K/s' is the bandwidth used by the
client. You can track down who's starving your bandwidth with this.
The 'pureftp-who' command accepts interesting options:
'-c': the program is called via a web server (CGI interface) . Output is a
full HTML page with the initial content-type header. This option is
automatically enabled if an environment variable called GATEWAY_INTERFACE is
found. This is the default if you can access the program from a CGI-enabled web
server (Apache, Roxen, Caudium, WN, ...) .
'-h': show command-line options summary.
'-n': don't resolve host names and only show IP addresses (faster).
'-s': output an easily parsable format for shell scripts (but not very user
friendly) .
There's only one line per client, with only numeric data, delimited by a '|'
character. It's not very human-readable, but it's designed for easy parsing by
shell scripts (cut/sed) . '|' characters in user names or file names are
quoted ('|' becomes '\|') .
Type 'pure-ftpwho -h' to check the format.
'-w': output a complete HTML page (web mode).
'-W': output an HTML page with no header and no footer. This is an embedded
mode, suitable for inline calls from CGI, SSI or PHP scripts.
'-x': output well-formed XML data for post-processing. This is the most
acurate mode. Time is in seconds and file sizes are in bytes (in other
output formats, sizes are in kbytes for easier readability) .
'-v': verbose output in text mode. Additional info includes the size of
files being downloaded/uploaded, the local IP or local host name and the
connection port. This is especially useful for virtual hosts. Here's a
sample output of 'pure-ftpwho -v':
+------+---------+-------+------+-------------------------------------------+
| PID | Login |For/Spd| What | File/Remote IP/Size(Kb)/Local IP |
+------+---------+-------+------+-------------------------------------------+
| 9086 | j | 00:04 | DL | linux-2.4.4.tar.bz2 |
| '' | '' | 22K/s| 27% | -> localhost |
| '' | '' | | | Total size: 20859 Transfered: 5632 |
| '' | '' | | | <- localhost:21 |
+------+---------+-------+------+-------------------------------------------+
------------------------ AFTER AN UPLOAD ------------------------
After an upload, any external program or shell script can be spawned with the
name of the newly uploaded file as an argument. You can use that feature to
automatically send a mail when a new file arrives. Or you can pass it to a
moderation system, an anti-virus, a MD5 signature generator or whatever you
decide can be done with a file.
To support this, the server has to be configured --with-uploadscript at
compilation time. Upload scripts won't be spawned on unreadable directories.
So it's highly recommended to use upload scripts with the --customerproof
run-time option and without unreadable parent directories.
To tell the FTP server to use upload scripts, it has to be launched with the
'-o' option. Finally, you have to run another daemon called 'pure-uploadscript'
provided by this package.
IMPORTANT:
YOU MUST START PURE-FTPD _FIRST_ and _THEN_ START PURE-UPLOADSCRIPT.
THE REVERSE ORDER WON'T WORK.
For security purposes, the server never launches any external program. It's
why there is a separate daemon, that reads new uploads pushed into a named
pipe by the server. Uploads are processed synchronously and sequencially.
It's why on loaded or untrusted servers, it might be a bad idea to use
pure-uploadscript with lenghty or cpu-intensive scripts.
The easiest way to run pure-uploadscript is 'pure-uploadscript -r <script>':
/usr/local/sbin/pure-uploadscript -r /bin/antivirus.sh
The absolute path of the newly uploaded file is passed as a first argument.
Some environment variables are also filled with interesting values:
- UPLOAD_SIZE : the size of the file, in bytes.
- UPLOAD_PERMS : the permissions, as an octal value.
- UPLOAD_UID : the uid of the owner.
- UPLOAD_GID : the group the file belongs to.
- UPLOAD_USER : the name of the owner.
- UPLOAD_GROUP : the group name the file belongs to.
- UPLOAD_VUSER : the full user name, or the virtual user name. (127 chars max)
There are also some options to "pure-uploadscript":
- '-u <uid>' and '-g <gid>' to switch the account pure-uploadscript will run
as. The script will be spawned with the same identity.
- '-B' to fork in background.
Please have a look at the man page ('man pure-uploadscript') for additional
info.
------------------------ LISTING DIRECTORIES ------------------------
The built-in 'ls' supports all common options of a regular 'ls' command.
Here are the ones you should know for a better life with FTP:
- '-l': verbose listing, reporting dates, owners, perms and sizes.
- '-a': also lists files and directories beginning with a dot.
- '-F': adds a '/' after directory names.
- '-d': list the directory itself, not its content.
- '-R': recursive listing.
- '-S': sort by size.
- '-t': sort by date.
- '-r': reverse the sorting order.
If you aren't very familiar with Unix, log in to your FTP server and try
these variants:
ls
ls -F
ls -l
ls -la
ls -lR
ls -Sl
ls -Slr
ls -tl
ls -tlr
Globbing is also supported. So if you are looking for a GNOME RPM in
<I don't know the directory name>/gnome-xxxxxxxx.rpm , you can find it that
way:
ls */gnome*.rpm
------------------------ VIRTUAL QUOTAS ------------------------
With virtual quotas, you can restrict the maximum number of files and the
total size of a user directory.
These quotas are "virtual" because they aren't handled at kernel-level, but
by the FTP server itself. There are some advantages over kernel quotas:
- Virtual quotas are specific to the FTP server. You can have different
system quotas to handle other files (eg. mail) on the same partition.
- You can have different virtual quotas for every user, even if they share
the same system uid.
- Virtual quotas are working even on filesystems that don't support system
quotas.
However, virtual quotas are slower and can't be as reliable as kernel quotas,
so don't trust them ultimately, they are probably races allowing to bypass
them. Also the filesystem users directories are on must properly support file
locking.
Virtual quotas are implemented in Pure-FTPd as simple files called
".ftpquota", located in the home directory of chrooted users. This file only
contains two numbers: the current number of files for this user and the
total size of the directory (+ its subdirectories), in bytes. When a new
file is uploaded, these numbers grow. When a file is deleted, these numbers
get smaller. Simple. Of course, when virtual quotas are enabled for one
user, that user must be 1) chrooted, 2) not allowed to write quota files, 3)
not allowed to forbid access to some directories to fool the counter.
Quotas can be enabled for all users for the -n (--quotas) option. This
option is followed by the max number of files and the max size (in Megabytes)
. Every user will have the same quota. Exception: members of the trusted
group, if -a is enabled.
You can also have different quotas for every user if you use PureDB or SQL
databases. See the "README.Virtual-Users" file for more info about PureDB
databases.
So, if you want 1000 files max and 10 Mb max for all your customers, run
the server like this:
/usr/local/sbin/pure-ftpd -n 1000:10
".ftpquota" files are created on demand when they are missing. However, when
they are created, the server assumes that the account was empty. If this is
not the case, you must run the "pure-quotacheck" utility to create an
initial ".ftpquota" file.
"pure-quotacheck" is a tool that computes the size and the number of files
in a directory and create a ".ftpquota" file with this info.
The syntax is:
pure-quotacheck -u username/uid -d home directory [-g group/gid]
For instance, if you want to summarize usage for the /home/ftpusers/john
directory, whose files are owned by the "ftpusers" system account, just run:
pure-quotacheck -u ftpusers -d /home/ftpusers/john
You can run pure-quotacheck whenever you want, even when ".ftpquota" files
are already there. This is even a good idea to run this for all users in
crontab, so that stored quotas are always exact, even if something went wrong
(server bug, filesystem corruption, savagely killed server, etc) .
------------------------ AUTHENTICATION ------------------------
Pure-FTPd supports multiple methods of authentication. To use a method, you
must have it compiled in (check the ./configure options) .
- To use Unix authentication (the traditional /etc/passwd file), add the
following option when you run the server:
-l unix
- To use PAM authentication, add this:
-l pam
- To use PureDB (virtual users), add this:
-l puredb:/path/to/puredb_database
(read README.Virtual-Users for more info about PureDB indexed files)
- To use LDAP directories, add this:
-l ldap:/path/to/ldap_config_file
(read README.LDAP for more info about LDAP directories)
- To use MySQL databases, add this:
-l mysql:/path/to/mysql_config_file
(read README.MySQL for more info about MySQL databases)
- To use Postgres databases, add this:
-l pgsql:/path/to/postgres_config_file
(read README.PGSQL for more info about Postgres databases)
- To use external authentication handlers (with pure-authd), use:
-l extauth:/path/to/authd/socket
(read README.Authentication-Modules for more info about external
authentication)
Multiple authentication methods can be chained. For instance, you can run the
server like this:
/usr/local/sbin/pure-ftpd -lldap:/etc/pureftpd-ldap.conf \
-lpuredb:/etc/pureftpd.pdb -lunix
Every method is tried in order. With the previous command line, an LDAP
directory is probed first. If a user isn't found in the directory, a
PureDB database is scanned for the same user name. If that user is still not
found, /etc/passwd is scanned.
If the user is found in the LDAP directory, but the given password is wrong,
further authentication methods are skipped.
If you don't specify any -l option, PAM is assumed by default if the server
is compiled with PAM support and Unix is assumed by default otherwise.
------------------------ DIRECTORY ALIASES ------------------------
Directory aliases provides "shortcuts" for the "cd" command. For instance,
if you define an alias called "pictures" for "/usr/misc/pictures", when an
user will type "cd pictures" and if no real "pictures" directory exists, he
will be automatically redirected to "/usr/misc/pictures". Unlike symbolic
links, "cd pictures" will work from any directory. Tildes are *not* expanded.
a user can get the list of available aliases with the following command:
SITE ALIAS
To support that feature, the server must be compiled with --with-diraliases
passed to ./configure .
To define alias/directory pairs, you must create a file called
/etc/pureftpd-dir-aliases, whose format is:
Alternating lines of alias and dir
(this enables embeded whitespace in dir and alias without quoting rules)
Optional blank lines
Optional lines beginning with '#' as comments
(no you can't put a '#' just anywhere)
Example:
pictures
/usr/misc/pictures
sources
/usr/src
# This is for the OpenBSD port tree
pureftpd-port
/usr/ports/net/pure-ftpd
------------------------ PRIVILEGE SEPARATION ------------------------
When privilege separation is enabled, each session will spawn two processes :
a "privileged" process running as root, but that can only do very basic
and trusted actions (binding a port and remove the ftpwho scoreboard) and
the "client" process. The "client" process definitely revokes all privileges
after authentication and chroot() and punctually communicates with the
parent over a private channel.
Privilege separation decreases performance of loaded servers, but it
increases security and reliability. Enabling it is recommended.
Some old broken operating systems may allow the ptrace() system call on
processes that revoked privileges. On these platforms, enabling privilege
separation is a bad idea if untrusted users also have shell access. Use the
src/ptracetest program to check this. At least Solaris, ISOS, MirBSD,
OpenBSD, DragonflyBSD, FreeBSD and Linux are known to be safe.
------------------------ CHARSETS (RFC2640) ------------------------
Since version 1.0.21, pure-ftpd has *experimental* support for charsets
conversion. The server filesystem can use a different charset than the
charset assumed by clients, and pure-ftpd translates file names through the
iconv library.
Some modern clients like lftp will also try to use UTF-8 if the server
supports it.
Thus, charsets conversion can be very useful when dealing with file names
containing non-english characters.
In order to support this, pure-ftpd has to be compiled with:
./configure ... --with-rfc2640
This is not supported by default because it requires libiconv.
Then the server has to be started with --fscharset=<charset>. Replace
<charset> with the charset of the server's filesystem. For instance:
/usr/local/sbin/pure-ftpd --fscharset=ISO-8859-15
This is often enough to properly work with UTF-8 capable clients.
But optionnally, you can specify the default charset for clients, with
--clientcharset:
/usr/local/sbin/pure-ftpd --fscharset=iso-8859-15 --clientcharset=big5
------------------------ OPTIMIZING FOR HIGH LOAD ------------------------
If you are going to use Pure-FTPd on a highly loaded server, here are some
hints to get the best performances:
- Compile with:
env CFLAGS="-O2 -fomit-frame-pointer -fgcse -Os" ./configure --with-minimal --without-inetd --without-pam
make install-strip
- Run it in standalone mode. Don't use -C, don't enable pure-ftpwho nor
pure-uploadscript (-o), nor per-user limits (-y) .
- Increase your system max descriptors number and local port range. On a
Linux kernel, you can try:
echo 2000 > /proc/sys/fs/super-max
echo 60000 > /proc/sys/fs/file-max
ulimit -n 60000
echo 30000 65534 > /proc/sys/net/ipv4/ip_local_port_range
- On a Linux kernel, disable syncookies, ecn, timestamps and window scaling:
echo 0 > /proc/sys/net/ipv4/tcp_syncookies
echo 0 > /proc/sys/net/ipv4/tcp_ecn
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
- Disable access time update on your mounted filesystems. On a Linux system,
just add 'noatime,nodiratime' for each mount point in your /etc/fstab file.
- Disable syslog output and DNS lookups. Run it with:
/usr/local/sbin/pure-ftpd -f none -H
For FreeBSD, DJ_Oggy recommends the following setting:
>>> QUOTE:
Drop into single user mode (do a shutdown now or boot -s) and enter
tunefs -n enable <filesystem>
i sugest / /usr /var
In /etc/fstab add ",noatime" to the options of all filesystems.
In /boot/loader.conf add the following:
hw.ata.wc="1"
kern.ipc.nmbclusters="60000"
In /etc/sysctl.conf add the following:
vfs.vmiodirenable=1
kern.ipc.maxsockbuf=2097152
kern.ipc.somaxconn=8192
kern.ipc.maxsockets=16424
kern.maxfiles=65536
kern.maxfilesperproc=32768
net.inet.tcp.rfc1323=1
net.inet.tcp.delayed_ack=0
net.inet.tcp.sendspace=65535
net.inet.tcp.recvspace=65535
net.inet.udp.recvspace=65535
net.inet.udp.maxdgram=57344
net.local.stream.recvspace=65535
net.local.stream.sendspace=65535
give it two asprin, a reboot and call me in the morning!!!!!
<<< END OF QUOTE
2012年8月28日 星期二
pure-ftpd argument
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