Run a simple, single-user ftp server instantly from the command line to enable easy file transfer between two machines. no installation required, fully portable executable for Windows, Mac OS X and Linux.

sfk ftpserv [-h[elp]] [-port=nport] [-rw] [workdir]

The SFK Instant FTP Server for easy file transfer.

default behaviour since SFK
* the CURRENT DIRECTORY is made accessible, WITH subdirs.
* any kind of directory traversal (.., / etc.) is blocked.
* just ONE CLIENT (browser etc.) can connect at a time.
  if another client connects, the first is auto closed.
* after 60 seconds of inactivity, the connection is closed.
* filenames with accents are sent as is (no UTF8 support).
* with -rw, files of any size can be written (no size limit).
* with -rw, existing files are overwritten without asking.

only for trusted environments!
  sfk ftpserv is intended only for personal file transfer
  between two machines that the user has control of, within
  a trusted LAN environment. it should not be used to offer
  files in the internet. if security is important then do not
  use sfk ftpserv but a full scale FTP server like FileZilla.

  -port=n     use other port than default, e.g. -port=10000.
  -port2=n    alternative port, used if first port fails.
              use -port2=0 to disable alternative port.
  -pasvport=n define a fixed port for PASV connections.
              default is to allocate a random port defined
              by the operating system.
  -pw=x       require primitive authentication, i.e. client
              must provide password x to login. you may also
              set an environment variable like:
                 set SFK_FTP_PW=mypassword
              or set SFK_FTP_SPW=mypassword
              with the latter one being used only by the
              sfk ftpserv command, but not by sfk ftp.
  -user=x     require this username. if not specified then
              any username can be used. can also be given
              by environment variable SFK_FTP_USER
              or SFK_FTP_SUSER.
  -timeout=n  set timeout to n seconds. default is 60.
  -rw         allow read+write access. default is readonly.
  -notify=h   display an arrow in SFKTray 1.1 running on
              hostname h whenever files are actually sent.
  -maxsize=n  set size limit per file write to this, e.g.
              10m = 10 mbytes. default is no size limit.
  -minspace=n set required free disk space for file writing,
              e.g. -minspace=200m requires 200 megabytes.
  -noclone    do not try to replicate time stamps on a file
              transmission from an sfk ftp client.
  -verbose[=2]  list the transmitted ftp commands.
              helpful to get more infos in case of errors.
  -showerr[or]  print all sent 5xx replies to terminal,
              except for 550 no such file. default is to
              print them only with -verbose.
  -quiet[=2]  print less or no status informations.
  -nosub      block sub directory access, e.g. the client
              may NOT say "put the/sub/dir/document.txt".
  -run        allow client to execute system commands.
              requires -pw option being set as well.
              requires an sfk ftp client to run commands.
  -runpw=x    require authentication only for run commands.
              can also be set via the environment:
                 set SFK_FTP_RUNPW=mypassword
              or set SFK_FTP_SRUNPW=mypassword
  -ownip=x    if client sends PASV command, by default the
  -ownip x    server replies with the first network interface
              IP found. if this is the wrong one, you may
              supply a different IP here (as n.n.n.n).
  -noclose    do not auto close first client connection
              if another client tries to connect.

specific single work dir:
   instead of making the current directory accessible
   you may set a folder name like sfk ftpserv mydir
   to allow access to these contents only.

multi directory mappings:
   instead of making the current directory accessible
   you may specify folders (with virtual names) like:
      -usedir C:\audiofiles D:\images=pic

   sfk sftserv   same as sfk ftpserv but using port 2121.
   sfk fileserv  same as sfk sftserv.

transfer protocol selection
   since SFK 1.8.5, when using "sfk ftpserv" at the server
   and "sfk ftp" at the windows client, plain FTP protocol
   is used to avoid firewall restrictions via port 21.
   to use SFT Simple File Transfer for better connectivity
   and cput/cget support run the server as "sfk sftserv"
   and the client as "sfk sft", which will use port 2121.

file attributes
   since SFK 1.6.7, when using the SFT protocol,
   linux file attributes are sent and written at the receiver,
   except for file owner 'rw' flags which are set by default
   to allow rewrite in future transfers. when sending from
   linux to windows attributes like 'x' get lost.

problems and solutions:

if you try to login to the server using a regular ftp client, but
you cannot connect and/or transfer files, then usually there is a
firewall or network configuration incompatible to normal FTP.

- if your ftp client provides a command "passive", then type that,
  press enter, and then try the usual commands like dir, get or put.

- use "sfk sftserv" at the server and "sfk sft" at the client.
  this will use a different protocol (SFT) via port 2121 with
  which you often can transfer files even if normal FTP fails.

- Windows: the firewall may stop sfk to sfk file transfer on
  port 21, with error ECONNRESET, if your sfk client is old.
  use the sfk 1.8.5 ftp client which uses plain FTP.

- Windows 7 Starter: you may have to open the firewall settings
  and enable incoming connections for application "sfk" manually.

- Windows: whenever running sfk.exe in an ununsual user context,
  e.g. from a mounted virtual drive, or a non-admin shell, this
  may cause the system to block incoming connections.

- some FTP clients must be configured not to use multiple transfer
  connections in parallel (FileZilla: edit/settings/transfers)

- virtual machines: when using NAT network adapter mode you may
  not connect from the host into the guest but only vice versa.
  you may configure port forwards in the VM's adapter settings,
  then connect to but not to the IP shown
  in the guest. also read the VM's help on adapter modes.

known compatible ftp clients:
  WinSCP (in FTP mode), WS_FTP95, FileZilla, command line ftp

known incompatible ftp clients:
  Windows Explorer FTP (requires unsupported multi connections)

see also
  sfk ftp       the sfk ftp client
  sfk sft       the sfk sft client
  sfk httpserv  the sfk instant http server

web reference


- to run a 'real' ftp server (port 21) for non sfk clients:

  sfk ftpserv -user=foo -pw=bar mydir
    require the given user/pw and allow read only access to mydir
    and all subdirectories of mydir.

  sfk ftpserv -rw -usedir website/images=pic /Musik/audio=audio
    allow read/write access to website/images with virtual folder
    name "pic" and to /Musik/audio as just "audio".

- if you just want quick and simplest file transfer between two
  machines both having sfk, use this:

  sfk sftserv -rw
    run an sfk simple file transfer server, using port 2121,
    allowing read/write access to current dir and all sub dirs.
    then use "sfk sft" at the client side. should no connection
    be possible run the server and/or client with admin rights
    and check the firewall settings.

file transfer between windows and vmware linux

   the sfk ftpserv function was originally created to enable file transfer
   between a windows host and vmware guest OS, as I saw no other way
   to accomplish this.

   for more infos, read on here.