The
file specifies various configuration options for
ftpd(8)
that apply once a user has authenticated their connection.
consists of a series of lines, each of which may contain a
configuration directive, a comment, or a blank line.
Directives that appear later in the file override settings by previous
directives.
This allows
`wildcard'
entries to define defaults, and then have class-specific overrides.
A directive line has the format:
command class [arguments]
A
``\''
is the escape character; it can be used to escape the meaning of the
comment character, or if it is the last character on a line, extends
a configuration directive across multiple lines.
A
``#''
is the comment character, and all characters from it to the end of
line are ignored (unless it is escaped with the escape character).
Each authenticated user is a member of a
class
which is determined by
ftpusers(5).
class
is used to determine which
entries apply to the user.
The following special classes exist when parsing entries in
:
all
Matches any class.
none
Matches no class.
Each class has a type, which may be one of:
GUEST
Guests (as per the
``anonymous''
and
``ftp''
logins).
A
chroot(2)
is performed after login.
The
ftpd(8)
STAT
command will return the class settings for the current user as defined by
,
unless the
private
directive is set for the class.
Each configuration line may be one of:
advertize class [host
]
Set the address to advertise in the response to the
PASV
and
LPSV
commands to the address for
host
(which may be either a host name or IP address).
This may be useful in some firewall configurations, although many
ftp clients may not work if the address being advertised is different
to the address that they've connected to.
If
class
is
``none''
or
host
not is specified, disable this.
checkportcmd class [off
]
Check the
PORT
command for validity.
The
PORT
command will fail if the IP address specified does not match the
FTP
command connection, or if the remote TCP port number is less than
IPPORT_RESERVED
It is
strongly
encouraged that this option be used, especially for sites concerned
with potential security problems with
FTP
bounce attacks.
If
class
is
``none''
or
off
is specified, disable this feature, otherwise enable it.
chroot class [pathformat
]
If
pathformat
is not specified or
class
is
``none''
use the default behavior (see below).
Otherwise,
pathformat
is parsed to create a directory to create as the root directory with
chroot(2)
into upon login.
pathformat
can contain the following escape strings:
Escape
Description
"%c"
Class name.
"%d"
Home directory of user.
"%u"
User name.
"%%"
A
``%''
character.
The default root directory is:
CHROOT
The user's home directory.
GUEST
If
-a anondir
is specified, use
anondir
otherwise the home directory of the
`ftp'
user.
Define an automatic in-line file conversion.
If a file to retrieve ends in
suffix
and a real file (sans
suffix
exists, then the output of
command
is returned instead of the contents of the file.
suffix
The suffix to initiate the conversion.
type
A list of valid filetypes for the conversion.
Valid types are:
`f'
(file), and
`d'
(directory).
disable
The name of file that will prevent conversion if it exists.
A file name of
``.
''
will prevent this disabling action
(i.e., the conversion is always permitted.)
command
The command to run for the conversion.
The first word should be the full path name
of the command, as
execv(3)
is used to execute the command.
All instances of the word
``%s''
in
command
are replaced with the requested file (sans
suffix )
Conversion directives specified later in the file override earlier
conversions with the same suffix.
denyquick class [off
]
Enforce
ftpusers(5)
rules after the
USER
command is received, rather than after the
PASS
command is received.
Whilst enabling this feature may allow information leakage about
available accounts (for example, if you allow some users of a
REAL
or
CHROOT
class but not others), it is useful in preventing a denied user
(such as
`root'
from entering their password across an insecure connection.
This option is
strongly
recommended for servers which run an anonymous-only service.
If
class
is
``none''
or
off
is specified, disable this feature, otherwise enable it.
display class [file
]
If
file
is not specified or
class
is
``none''
disable this.
Otherwise, each time the user enters a new directory, check if
file
exists, and if so, display its contents to the user.
Escape sequences are supported; refer to
Sx Display file escape sequences
in
ftpd(8)
for more information.
hidesymlinks class [off
]
If
class
is
``none''
or
off
is specified, disable this feature.
Otherwise, the
LIST
command lists symbolic links as the file or directory the link
references
(``ls -LlA
''
)
Servers which run an anonymous service may wish to enable this
feature for
GUEST
users, so that symbolic links do not leak names in
directories that are not searchable by
GUEST
users.
homedir class [pathformat
]
If
pathformat
is not specified or
class
is
``none''
use the default behavior (see below).
Otherwise,
pathformat
is parsed to create a directory to change into upon login, and to use
as the
`home'
directory of the user for tilde expansion in pathnames, etc.
pathformat
is parsed as per the
chroot
directive.
The default home directory is the home directory of the user for
REAL
users, and
/
for
GUEST
and
CHROOT
users.
limit class
[count [file
]
]
Limit the maximum number of concurrent connections for
class
to
count
with
`-1'
meaning unlimited connections.
If the limit is exceeded and
file
is specified, display its contents to the user.
If
class
is
``none''
or
count
is not specified, disable this.
If
file
is a relative path, it will be searched for in
/etc
(which can be overridden with
-c confdir
maxfilesize class [size
]
Set the maximum size of an uploaded file to
size
with
`-1'
meaning unlimited connections.
If
class
is
``none''
or
size
is not specified, disable this.
maxtimeout class [time
]
Set the maximum timeout period that a client may request,
defaulting to two hours.
This cannot be less than 30 seconds, or the value for
timeout
If
class
is
``none''
or
time
is not specified, use the default.
mmapsize class [size
]
Set the size of the sliding window to map a file using
mmap(2).
If zero,
ftpd(8)
will use
read(2)
instead.
The default is zero.
An optional suffix may be provided as per
rateget
This option affects only binary transfers.
If
class
is
``none''
or
size
is not specified, use the default.
modify class [off
]
If
class
is
``none''
or
off
is specified, disable the following commands:
CHMODDELEMKDRMDRNFR
and
UMASK
Otherwise, enable them.
motd class [file
]
If
file
is not specified or
class
is
``none''
disable this.
Otherwise, use
file
as the message of the day file to display after login.
Escape sequences are supported; refer to
Sx Display file escape sequences
in
ftpd(8)
for more information.
If
file
is a relative path, it will be searched for in
/etc
(which can be overridden with
-c confdir
notify class [fileglob
]
If
fileglob
is not specified or
class
is
``none''
disable this.
Otherwise, each time the user enters a new directory,
notify the user of any files matching
fileglob
passive class [off
]
If
class
is
``none''
or
off
is specified, prevent passive
( PASVLPSV
and
EPSV
connections.
Otherwise, enable them.
portrange class [min max
]
Set the range of port number which will be used for the passive data port.
max
must be greater than
min
and both numbers must be be between
IPPORT_RESERVED
(1024) and 65535.
If
class
is
``none''
or no arguments are specified, disable this.
private class [off
]
If
class
is
``none''
or
off
is specified, do not display class information in the output of the
STAT
command.
Otherwise, display the information.
rateget class [rate
]
Set the maximum get
(RETR
)
transfer rate throttle for
class
to
rate
bytes per second.
If
rate
is 0, the throttle is disabled.
If
class
is
``none''
or
rate
is not specified, disable this.
An optional suffix may be provided, which changes the interpretation of
rate
as follows:
b
Causes no modification.
(Default; optional)
k
Kilo; multiply the argument by 1024
m
Mega; multiply the argument by 1048576
g
Giga; multiply the argument by 1073741824
t
Tera; multiply the argument by 1099511627776
rateput class [rate
]
Set the maximum put
(STOR
)
transfer rate throttle for
class
to
rate
bytes per second,
which is parsed as per
rateget rate
If
class
is
``none''
or
rate
is not specified, disable this.
readsize class [size
]
Set the size of the read buffer to
read(2)
a file.
The default is the file system block size.
An optional suffix may be provided as per
rateget
This option affects only binary transfers.
If
class
is
``none''
or
size
is not specified, use the default.
recvbufsize class [size
]
Set the size of the socket receive buffer.
An optional suffix may be provided as per
rateget
The default is zero and the system default value will be used.
This option affects only passive transfers.
If
class
is
``none''
or
size
is not specified, use the default.
sanenames class [off
]
If
class
is
``none''
or
off
is specified, allow uploaded file names to contain any characters valid for a
file name.
Otherwise, only permit file names which don't start with a
`.'
and only comprise of characters from the set
``[-+,._A-Za-z0-9]''
sendbufsize class [size
]
Set the size of the socket send buffer.
An optional suffix may be provided as per
rateget
The default is zero and the system default value will be used.
This option affects only binary transfers.
If
class
is
``none''
or
size
is not specified, use the default.
sendlowat class [size
]
Set the low water mark of socket send buffer.
An optional suffix may be provided as per
rateget
The default is zero and system default value will be used.
This option affects only for binary transfer.
If
class
is
``none''
or
size
is not specified, use the default.
template class [refclass
]
Define
refclass
as the
`template'
for
class
any reference to
refclass
in following directives will also apply to members of
class
This is useful to define a template class so that other classes which are
to share common attributes can be easily defined without unnecessary
duplication.
There can be only one template defined at a time.
If
refclass
is not specified, disable the template for
class
timeout class [time
]
Set the inactivity timeout period.
(the default is fifteen minutes).
This cannot be less than 30 seconds, or greater than the value for
maxtimeout
If
class
is
``none''
or
time
is not specified, use the default.
umask class [umaskval
]
Set the umask to
umaskval
If
class
is
``none''
or
umaskval
is not specified, set to the default of
027
upload class [off
]
If
class
is
``none''
or
off
is specified, disable the following commands:
APPESTOR
and
STOU
as well as the modify commands:
CHMODDELEMKDRMDRNFR
and
UMASK
Otherwise, enable them.
writesize class [size
]
Limit the number of bytes to
write(2)
at a time.
The default is zero, which means all the data available as a result of
mmap(2)
or
read(2)
will be written at a time.
An optional suffix may be provided as per
rateget
This option affects only binary transfers.
If
class
is
``none''
or
size
is not specified, use the default.
DEFAULTS
The following defaults are used:
checkportcmd all
classtype chroot CHROOT
classtype guest GUEST
classtype real REAL
display none
limit all -1 # unlimited connections
maxtimeout all 7200 # 2 hours
modify all
motd all motd
notify none
passive all
timeout all 900 # 15 minutes
umask all 027
upload all
modify guest off
umask guest 0707
