ftpaccess(4tcp)

Description

The following access capabilities are defined:

autogroup groupname class [class ...]

If an anonymous user is a member of any of class, the FTP server will perform a setegid to groupname. This allows access to group and owner read-only files and directories to a particular class of anonymous users. groupname is a valid group from /etc/group.

class classname typelist addrglob [addrglob ...]

Define the name of a class (classname) of users, with source addresses of the form addrglob. addrglob may be a globbed domain name or a globbed numeric address. Multiple members of classname may be defined. There may be multiple class commands listing additional members of the class. If multiple class commands can apply to the current session, the first one listed in the access file is used. Failing to define a valid class for a host will cause access to be denied. typelist is a comma-separated list of any of the keywords anonymous, guest and real. If the real keyword is included, the class can match users using FTP to access real accounts, and if the anonymous keyword is included the class can match users using anonymous FTP. The guest keyword matches guest access accounts (see the guestgroup keyword for more information).

deny addrglob [message_file]

Always deny access to host(s) matching addrglob and display message_file. addrglob may be a globbed domain name or a globbed numeric address. If addrglob is !nameserved, access is denied to sites whose IP address cannot be resolved to a domain name. The message_file can contain magic cookies. See ``Magic cookies'' for more information.

guestgroup groupname [groupname ...]

If a real user is a member of any of groupname, the session is set up exactly as with anonymous FTP. In other words, a chroot is done, and the user is no longer permitted to issue the USER and PASS commands. groupname is a valid group from /etc/group.

The home directory field of a guest user's entry in /etc/passwd is divided into two parts separated by ``/./''. The first part is the pathname of the directory which will become the guest group's root directory via a chroot call. This directory must be set up in exactly the same way as the root directory for anonymous FTP. The second part is the pathname of the guest user's home directory relative to the guest group's root directory.

For example, in /etc/passwd, the real entry is:

guest1:x:100:92:Guest Account:/home/guests/./guest1:/bin/true

When guest1 successfully logs in, the FTP server will chroot to /home/guests and then chdir to /guest1. The guest user will only be able to access the directory structure under /guest1 (which will look and act as / to guest1), just as an anonymous FTP user would. Note that for a guest login to succeed, the user's shell (/bin/true in this example) must be listed in /etc/shells.

limit class n Times [message_file]

Limit class to n users at the times specified by Times, displaying message_file if user is denied access. Limit check is performed at login time only. If multiple limit commands can apply to the current session, the first applicable one is used. Failing to define a valid limit, or a limit of -1, is equivalent to unlimited. The Times field has the format:

day[day...][times][|day[day...][times]]...

day is one of Su, Mo, Tu, We, Th, Fr, Sa, Wk for any weekday (Mo through Fr), or Any for any day.

times defines a range of allowed times in 24-hour clock notation. For example, 0800-1230 represents the times of day from 8:00 A.M. to 12:30 P.M. If the time is not specified, any time of day is matched. Note that a time range that spans 0000 hours is permitted. For example, 0800-0600 means any time other than between 6:00 A.M. and 8:00 A.M.

Multiple day and times may be specified if separated by ``|''. For example, the entry ``Wk1700-0800|Sa|Su'' specifies 5:00 P.M. to 8:00 A.M., Monday through Friday, and any time on Saturday and Sunday.

The message_file can contain magic cookies. See ``Magic cookies'' for more information.

loginfails number

Terminate the FTP connection after number login failures. The connection is also terminated after number consecutive unsuccessful attempts to become a a member of an enhanced access group (using SITE GROUP and SITE GPASS). The default value is 5.

noretrieve filename [filename ...]

Always deny retrieve-ability of these files. If the files are an absolute path specification (that is, begins with a ``/'' character) then only those files are marked un-gettable, otherwise all files matching the filename are refused transfer. For example:

noretrieve /etc/passwd core

specifies no one will be able to get the file /etc/passwd whereas they will be allowed to transfer a file passwd if it is not in /etc. On the other hand no one will be able to get files named core wherever they are.

No globbing is done.

private yes|no

If set to yes, a user can use the SITE GROUP and SITE GPASS commands to specify an enhanced access group and associated password after they log in. If the group name and password are valid, the user becomes (via setegid) a member of the group specified in the group access file /etc/ftpgroups. The format of the group access file is described in ftpgroups(4tcp).

NOTE: For this option to work for anonymous FTP users, the group access file is loaded into memory. This means that the necessary passwords and access privileges granted to users via SITE GROUP will be static for the duration of an FTP session.

banner path

Works similarly to the message command, except that the banner is displayed before the user enters the username/password. The path is relative to the real system root, not the base of the anonymous FTP directory.

There can be magic cookies in the file specified by path. See ``Magic cookies'' for more information.

WARNING: This command can completely prevent non-compliant FTP clients from making use of the FTP server. Not all clients can handle multi-line responses (which is how the banner is displayed).

email name

Defines the email address of the FTP archive maintainer. This string will be printed every time the ``%E'' magic cookie is used. See ``Magic cookies'' for more information.

lslong command [argument]

When doing long replies (multiline responses), for anonymous users use command with argument to list the contents of a directory on the remote machine. The default command is /bin/ls with argument -la.

lsshort command [argument]

When not doing long replies or for non anonymous users use command with argument to list the contents of a directory on the remote machine. The default command is /bin/ls with argument -la.

message path [when [class ...]]

Define a file with path such that ftpd will display the contents of the file to the user at login time or upon using the change working directory command. The when parameter may be ``LOGIN'' or ``CWD=dirglob''. If when is ``CWD=dirglob'', dirglob specifies the pattern of a directory which will trigger notification. A dirglob of ``'' matches all directories.

The optional class specification allows the message to be displayed only to members of a particular class. More than one class may be specified.

There can be magic cookies in the file specified by path. See ``Magic cookies'' for more information.

The message will only be displayed once to avoid annoying the user. Remember that when messages are triggered by an anonymous FTP user, path must be relative to the base of the anonymous FTP directory tree. For guest users, path must be relative to their root directory.

readme pathglob [when [class ...]]

Define a file with pathglob such that ftpd will notify the user at login time or upon using the change working directory command that the file exists and was modified on such-and-such date. The when parameter may be ``LOGIN'' or ``CWD=dirglob''. If when is ``CWD=dirglob'', dirglob specifies the pattern of a directory which will trigger the notification. A dirglob of ``'' matches all directories. The message will only be displayed once, to avoid bothering users. Remember that when readme messages are triggered by an anonymous FTP user, the pathglob must be relative to the base of the anonymous FTP directory tree.

The optional class specification allows the message to be displayed only to members of a particular class. More than one class may be specified.

log commands typelist

Enables logging of individual commands by users to syslog. typelist is a comma-separated list of any of the keywords anonymous, guest and real. If the real keyword is included, logging will be done for users using FTP to access real accounts, and if the anonymous keyword is included logging will done for users using anonymous FTP. The guest keyword matches guest access accounts (see guestgroup for more information).

log transfers typelist directions

Enables logging of file transfers for either real or anonymous FTP users to xferlog. Logging of transfers to the server (incoming) can be enabled separately from transfers from the server (outbound). typelist is a comma-separated list of any of the keywords anonymous, guest and real. If the real keyword is included, logging will be done for users using FTP to access real accounts, and if the anonymous keyword is included logging will done for users using anonymous FTP. The guest keyword matches guest access accounts (see guestgroup for more information). directions is a comma-separated list of any of the two keywords inbound and outbound, and will respectively cause transfers to be logged for files sent to the server and sent from the server.

alias string dir

Defines an alias, string, for a directory, dir. This can be used to add the concept of logical directories. For example:

alias   rfc:    /pub/doc/rfc

would allow the user to access /pub/doc/rfc from any directory with the command cd rfc:. Aliases only apply to the cd command.

cdpath dir

Defines an entry in the cdpath. This defines a search path that is used when changing directories.

For example:

cdpath /pub/packages
cdpath /.aliases

would allow the user to cd into any directory directly under /pub/packages or /.aliases directories. The search path is defined by the order the lines appear in the ftpaccess file.

If the user were to give the command:

cd foo

The directory will be searched for in the following order:

./foo
an alias called ``foo''
/pub/packages/foo
/.aliases/foo

The cdpath is only available with the cd command. If you have a large number of aliases you might want to set up an aliases directory with links to all of the areas you wish to make available to users.

compress yes|no classglob [classglob ...]

If set to yes, enables compress capabilities for any class matching any of classglob. The actual conversions are defined in the external file /etc/ftpconversions.

shutdown path

If the file specified by path exists, the server will check the file regularly to see if the server is going to be shut down. If a shutdown is planned, the user is notified, new connections are denied after a specified time before shutdown and current connections are dropped at a specified time before shutdown. The format of the file specified by path is:

year month day hour minute deny_offset disc_offset
text
...

where

year

any year > 1970

month

integer in the range 0-11

day

integer in the range 1-31

hour

integer in the range 0-23

minute

integer in the range 0-59

deny_offset

offset in hhmm format (hour and minute) before the shutdown time that new connections will be denied

disc_offset

offsets in hhmm format (hour and minute) before the shutdown time that existing connections will be disconnected

text

displayed to users logged into the FTP server to warn of disconnection. text can contain magic cookies. See ``Magic cookies'' for more information. The following additional magic cookies are available:

%d

time at which current connections will be dropped

%r

time at which new connections will be denied

%s

time at which system is going to shut down

All times are in the form:

ddd MMM DD hh:mm:ss YYYY

There can be only one shutdown command in the configuration file.

The external program ftpshut(1Mtcp) can be used to automate the process of generating this file.

To configure shutdowns for anonymous users, the file specified by path must exist relative to the base of the anonymous FTP directory tree. For guest users, path must exist relative to their root directory.

tar yes|no classglob [classglob ...]

If set to yes, enables tar capabilities for any class matching any of classglob. The actual conversions are defined in the external file /etc/ftpconversions.

virtual address root|banner|logfile path

Enables the virtual FTP server capabilities. address is the IP address of the virtual server. The second argument specifies that the path is one of:

root

The path to the root of the filesystem for this virtual server. This is used as the home directory of anonymous users accessing the virtual server. NOTE: root must be specified for the virtual server to be activated.

banner

The message presented to the user when connecting to a virtual server.

logfile

The file where transfers are recorded for a virtual server. If the path of the log file is not specified, the default log file (/var/adm/xferlog) will be used.

All other message files and permissions as well as any other settings in this file apply to all virtual servers.

chmod yes|no typelist

delete yes|no typelist

overwrite yes|no typelist

rename yes|no typelist

umask yes|no typelist

Allows or disallows the ability to perform the specified function (changing file modes, deleting files, overwriting files, renaming files, or setting their umask). By default, all users are allowed to perform these functions.

typelist is a comma-separated list of any of the keywords anonymous, guest and real.

passwd-check none|trivial|rfc822 [enforce|warn]

Defines the level and enforcement of password checking done by the server for anonymous FTP:

none

No password checking is performed (default behavior).

trivial

Password must contain an ``@''.

rfc822

Password must be an RFC 822 compliant address.

enforce

Warn the user, and then log them out.

warn

Warn the user, but allow them to log in (default behavior).

path-filter typelist message_file allowed_regexp [disallowed_regexp ...]

For users in typelist, path-filter defines the extended regular expressions (see grep(1)) that control what filename can or cannot be specified. typelist is a comma-separated list of any of the keywords anonymous, guest, and real. There may be multiple disallowed regular expressions. If a filename is invalid because it does not match the allowed regular expressions or because it matches one of the disallowed regular expressions, the message file (message_file) will be displayed to the user. For example:

path-filter anonymous /var/ftp/pathmsg ^[[:alnum:]-._]*$ ^[.-]

specifies that all upload filenames for anonymous users must be made of only alphanumeric characters and ``._-'', and may not begin with a ``.'' or a ``-''. If the filename is invalid, /var/ftp/pathmsg will be displayed to the user.

For anonymous users, message_file must be specified relative to the base of the anonymous FTP directory tree. For guest users, message_file must be specified relative to their root directory.

The message_file can contain magic cookies. See ``Magic cookies'' for more information.

upload home-dir dirpattern yes|no [owner group mode] [dirs|nodirs]

Define a directory with dirpattern that permits or denies uploads for users with a home directory of home-dir. A dirpattern of ``'' matches all directories to any level. A dirpattern of ``/pub/'' matches all directories below /pub to any level. Note that for an anonymous FTP user, dirpattern is assumed to be relative to home-dir.

If uploads are permitted, all uploaded files will be owned by owner and group and will have their permissions set according to mode.

Directories are matched on a best-match basis. For example:

upload  /home/ftp  *               no   nodirs
upload  /home/ftp  /incoming       yes  ftp  daemon  0666
upload  /home/ftp  /incoming/gifs  yes  jlc  guest   0600  nodirs

This would only allow uploads into /incoming and /incoming/gifs. Files that were uploaded to /incoming would be owned by ftp:daemon and would have permissions of 0666. File uploaded to /incoming/gifs would be owned by jlc:guest and have permissions of 0600.

The dirs and nodirs keywords can be specified to allow or disallow the creation or removal of subdirectories. The dirs keyword is assumed by default if neither dirs nor nodirs is specified. In the above example, creation and removal of directories would only be allowed in /incoming.

Magic cookies

%C

current working directory

%E

maintainer's email address as defined in ftpaccess

%F

free space in filesystem of CWD (in kilobytes)

%L

local host name

%M

maximum allowed number of users in this class

%N

current number of users in this class

%R

remote host name

%T

local time (form Thu Nov 15 17:12:42 1990)

%u

username as determined via RFC 931 authentication

%U

username given at login time

Files

References