ftpd(8)
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ftpd(8)




FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)


NAME

     ftpd - Internet File Transfer Protocol server


SYNOPSIS

     ftpd [ -d ] [ -v ] [ -l ] [ -t timeout ] [ -T maxtimeout ] [
     -a ] [ -A ] [ -L ] [ -i ] [ -I ] [ -o ] [ -p ctrlport ] [ -P
     dataport ] [ -q ] [ -Q ] [ -r rootdir ] [ -s ] [ -S ]  [  -u
     umask ] [ -V ] [ -w ] [ -W ] [ -X ]


DESCRIPTION

     Ftpd is the Internet File Transfer Protocol server  process.
     The  server  uses  the  TCP protocol and listens at the port
     specified in the ``ftp''  service  specification;  see  ser-
     vices(5).

     The -V option causes the program to  display  copyright  and
     version information, then terminate.

     If the -d or -v option is specified,  debugging  information
     is written to the syslog.

     If the -l option is specified, each ftp session is logged in
     the syslog.

     The ftp server will timeout an  inactive  session  after  15
     minutes.   If  the  -t  option  is specified, the inactivity
     timeout period will be set to timeout seconds.  A client may
     also  request a different timeout period; the maximum period
     allowed may be set to timeout seconds with  the  -T  option.
     The default limit is 2 hours.

     If the -a option is specified, the use of  the  ftpaccess(5)
     configuration file is enabled.

     If the -A option is specified, use of the ftpaccess(5)  con-
     figuration file is disabled. This is the default.

     If the -L option is specified, commands sent to the  ftpd(8)
     server will be logged to the syslog.  The -L option is over-
     ridden by the use of the ftpaccess(5) file.  If the -L  flag
     is  used,  command  logging will be on by default as soon as
     the ftp server is invoked.  This will cause  the  server  to
     log all USER commands, which if a user accidentally enters a
     password for that command  instead  of  the  username,  will
     cause passwords to be logged via syslog.

     If the -i option is specified, files received by the ftpd(8)
     server  will  be logged to the xferlog(5).  The -i option is
     overridden by the use of the ftpaccess(5) file.

     The -I option disables the use  of  RFC931  (AUTH/ident)  to
     attempt to determine the username on the client.

                    Last change: Jan 10, 1997                   1

FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)

     If the -o option is  specified,  files  transmitted  by  the
     ftpd(8)  server  will  be  logged to the xferlog(5).  The -o
     option is overridden by the use of  the  ftpaccess(5)  file.
     If  the -X option is specified, the output created by the -i
     and -o options is not saved to the xferlog  file  but  saved
     via  syslog  so you can collect output from several hosts on
     one central loghost.

     If the -u option is specified, the default umask is  set  to
     umask.

     If the -W option is specified user logins are  not  recorded
     in  the  wtmp  file.   The default ( -w ) is to record every
     login and logout.

     The -s and -S options place the daemon in standalone  opera-
     tion  mode.  The -S option runs the daemon in the background
     and is useful in startup scripts during  system  initializa-
     tion (ie., in rc.local).  The -s option leaves the daemon in
     foreground and  is  useful  when  running  from  init  (ie.,
     /etc/inittab).

     The -p and -P options override the port numbers used by  the
     daemon.  Normally, the daemon determines the port numbers by
     looking in /etc/services for "ftp" and "ftp-data".  If there
     is  no  /etc/services entry for "ftp-data" and the -P option
     is not specified, the daemon uses the port just prior to the
     control connection port.  The -p option is only available if
     running as a standalone daemon.

     The -q and -Q options deterine whether the daemon  uses  the
     PID  files.  These files are required by the limit directive
     to determine the number of  current  users  in  each  access
     class.   Disabling  the  use  of the PID files disables user
     limits.  The default (  -q  )  is  to  use  the  PID  files.
     Specify  -Q  when  testing  the server as a normal user when
     access permissions prevent the use of the PID files.  Large,
     busy  sites which do not wish to impose limits on the number
     of concurrent users may  also  consider  disabling  the  PID
     files.

     The -r option instructs  the  daemon  to  chroot(2)  to  the
     specified   rootdir  immedeately  upon  loading.   This  can
     improve system security by limiting the files which  may  be
     damaged  should  a breakin occur through the daemon.  Set is
     much like anonymous FTP, with additional files needed  which
     vary from system to system.

     The  ftp  server  currently  supports  the   following   ftp
     requests; case is not distinguished.

                    Last change: Jan 10, 1997                   2

FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)

     Request        Description
     ABOR           abort previous command
     ACCT           specify account (ignored)
     ALLO           allocate storage (vacuously)
     APPE           append to a file
     CDUP           change to parent of current working directory
     CWD            change working directory
     DELE           delete a file
     HELP           give help information
     LIST           give list files in a directory (``ls -lgA'')
     MKD            make a directory
     MDTM           show last modification time of file
     MODE           specify data transfer mode
     NLST           give name list of files in directory
     NOOP           do nothing
     PASS           specify password
     PASV           prepare for server-to-server transfer
     PORT           specify data connection port
     PWD            print the current working directory
     QUIT           terminate session
     REST           restart incomplete transfer
     RETR           retrieve a file
     RMD            remove a directory
     RNFR           specify rename-from file name
     RNTO           specify rename-to file name
     SITE           non-standard commands (see next section)
     SIZE           return size of file
     STAT           return status of server
     STOR           store a file
     STOU           store a file with a unique name
     STRU           specify data transfer structure
     SYST           show operating system type of server system
     TYPE           specify data transfer type
     USER           specify user name
     XCUP           change to parent of current working directory (deprecated)
     XCWD           change working directory (deprecated)
     XMKD           make a directory (deprecated)
     XPWD           print the current working directory (deprecated)
     XRMD           remove a directory (deprecated)

     The following non-standard or  UNIX  specific  commands  are
     supported by the SITE request.

     Request        Description
     UMASK          change umask. E.g. SITE UMASK 002
     IDLE           set idle-timer. E.g. SITE IDLE 60
     CHMOD          change mode of a file. E.g. SITE CHMOD 755 filename
     HELP           give help information. E.g. SITE HELP
     NEWER          list files newer than a particular date
     MINFO          like SITE NEWER, but gives extra information
     GROUP          request special group access. E.g. SITE GROUP foo
     GPASS          give special group access password. E.g. SITE GPASS bar

                    Last change: Jan 10, 1997                   3

FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)

     EXEC           execute a program.  E.g. SITE EXEC program params

     The remaining ftp requests specified in Internet RFC 959 are
     recognized,  but  not  implemented.   MDTM  and SIZE are not
     specified in RFC 959, but will appear in  the  next  updated
     FTP RFC.

     The ftp server will abort an active file transfer only  when
     the ABOR command is preceded by a Telnet "Interrupt Process"
     (IP) signal and a Telnet "Synch" signal in the command  Tel-
     net  stream,  as  described  in Internet RFC 959.  If a STAT
     command is received during a data transfer,  preceded  by  a
     Telnet IP and Synch, transfer status will be returned.

     Ftpd interprets file names  according  to  the  ``globbing''
     conventions  used  by  csh(1).  This allows users to utilize
     the metacharacters ``*?[]{}~''.

     Ftpd authenticates users according to four rules.

     1)   The user name  must  be  in  the  password  data  base,
          /etc/passwd, or whatever is appropriate for the operat-
          ing system, and the password must not be null.  In this
          case  a  password must be provided by the client before
          any file operations may be performed.

     2)   The  user  name   must   not   appear   in   the   file
          /etc/ftpusers.

     3)   The  user  must  have  a  standard  shell  returned  by
          getusershell(3).

     4)   If the  user  name  is  ``anonymous''  or  ``ftp'',  an
          anonymous  ftp  account must be present in the password
          file (user ``ftp'').  In this case the user is  allowed
          to  log  in  by  specifying any password (by convention
          this is given as the client host's name).

     In the last case, ftpd takes special  measures  to  restrict
     the  client's  access  privileges.   The  server  performs a
     chroot(2) command to the home directory of the ``ftp'' user.
     In  order that system security is not breached, it is recom-
     mended that the ``ftp'' subtree be  constructed  with  care;
     the following rules are recommended.

     ~ftp)
          Make the home directory owned by super-user and unwrit-
          able by anyone.

     ~ftp/bin)
          Make this directory owned by the super-user and unwrit-
          able  by  anyone.  The program ls(1) must be present to

                    Last change: Jan 10, 1997                   4

FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)

          support the list command.   This  program  should  have
          mode 111.

     ~ftp/etc)
          Make this directory owned by the super-user and unwrit-
          able  by anyone.  The files passwd(5) and group(5) must
          be present for the ls command to  be  able  to  produce
          owner  names  rather  than  numbers.  Depending  on the
          operating system, there may be  other  required  files.
          Check your manual page for the getpwent(3) library rou-
          tine.  The password field in passwd is  not  used,  and
          should  not  contain  real  encrypted passwords.  These
          files should be mode 444 and owned by  the  super-user.
          Don't use the system's /etc/passwd file as the password
          file or the system's /etc/group file as the group  file
          in the ~ftp/etc directory.

     ~ftp/pub)
          Create a subdirectory in ~ftp/pub with the  appropriate
          mode  (777 or 733) if you want to allow normal users to
          upload files.


AUTHENTICATION MECHANISM ON BSD/OS SYSTEMS ONLY

     The authentication mechanism used by ftpd is  determined  by
     the  ``auth-ftp''  entry  in  the  /etc/login.conf file (see
     login.conf(5)) that matches the users class.  If there is no
     ``auth-ftp''  entry for the class, the normal ``auth'' entry
     will be used instead.  An alternate authentication mechanism
     may  be  specified  by appending a colon (``:'') followed by
     the authentication style, i.e. ``joe:skey''.


GENERAL FTP EXTENSIONS

     There are some extensions to the FTP server such that if the
     user  specifies  a  filename (when using a RETRIEVE command)
     such that:

      True Filename  Specified Filename  Action
      -------------  ------------------  -----------------------------------
      <filename>.Z   <filename>          Decompress file before transmitting
      <filename>     <filename>.Z        Compress <filename> before
                                                 transmitting
      <filename>     <filename>.tar      Tar <filename> before transmitting
      <filename>     <filename>.tar.Z    Tar and compress <filename> before
                                                 transmitting

     Also, the FTP server will attempt to check for valid  e-mail
     addresses  and  chide  the user if he doesn't pass the test.
     For users whose FTP client will hang on "long replies" (i.e.
     multiline responses), using a dash as the first character of
     the password will disable the server's lreply() function.

                    Last change: Jan 10, 1997                   5

FTPD(8)               MAINTENANCE COMMANDS                FTPD(8)

     The FTP server can also log all file transmission and recep-
     tion,  keeping  the  following  information  for  each  file
     transmission that takes place.

     Mon Dec  3 18:52:41 1990 1 wuarchive.wustl.edu 568881 /files.lst.Z a _ o a chris@wugate.wustl.edu ftp 0 *

       %.24s %d %s %d %s %c %s %c %c %s %s %d %s
         1   2  3  4  5  6  7  8  9  10 11 12 13

       1 current time in the form DDD MMM dd hh:mm:ss YYYY
       2 transfer time in seconds
       3 remote host name
       4 file size in bytes
       5 name of file
       6 transfer type (a>scii, b>inary)
       7 special action flags (concatenated as needed):
             C   file was compressed
             U   file was uncompressed
             T   file was tar'ed
             _   no action taken
       8 file was sent to user (o>utgoing) or received from
         user (i>ncoming)
       9 accessed anonymously (r>eal, a>nonymous, g>uest) -- mostly for FTP
      10 local username or, if guest, ID string given
         (anonymous FTP password)
      11 service name ('ftp', other)
      12 authentication method (bitmask)
             0   none
             1   RFC931 Authentication
      13 authenticated user id (if available, '*' otherwise)


SEE ALSO

     ftp(1),  getusershell(3),  syslogd(8),  ftpaccess(5),  xfer-
     log(5), umask(2)


BUGS

     The anonymous account is  inherently  dangerous  and  should
     avoided when possible.

     The server must run as the super-user to create sockets with
     privileged  port numbers.  It maintains an effective user id
     of the logged in user, reverting to the super-user only when
     binding  addresses  to sockets.  The possible security holes
     have been extensively scrutinized, but are  possibly  incom-
     plete.

                    Last change: Jan 10, 1997                   6


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