NAME | SYNOPSIS | DESCRIPTION | SECURITY | SEE ALSO | HISTORY | AVAILABILITY | COLOPHON

TFTPD(8)                           iputils                          TFTPD(8)

NAME         top

       tftpd - Trivial File Transfer Protocol server

SYNOPSIS         top

       tftpd directory

DESCRIPTION         top

       tftpd is a server which supports the DARPA Trivial File Transfer
       Protocol (RFC1350). The TFTP server is started by inetd(8).

       directory is required argument; if it is not given tftpd aborts. This
       path is prepended to any file name requested via TFTP protocol,
       effectively chrooting tftpd to this directory. File names are
       validated not to escape out of this directory, however administrator
       may configure such escape using symbolic links.

       It is in difference of variants of tftpd usually distributed with
       unix-like systems, which take a list of directories and match file
       names to start from one of given prefixes or to some random default,
       when no arguments were given. There are two reasons not to behave in
       this way: first, it is inconvenient, clients are not expected to know
       something about layout of filesystem on server host. And second, TFTP
       protocol is not a tool for browsing of server's filesystem, it is
       just an agent allowing to boot dumb clients.

       In the case when tftpd is used together with rarpd(8), tftp
       directories in these services should coincide and it is expected that
       each client booted via TFTP has boot image corresponding its IP
       address with an architecture suffix following Sun Microsystems
       conventions. See rarpd(8) for more details.

SECURITY         top

       TFTP protocol does not provide any authentication. Due to this
       capital flaw tftpd is not able to restrict access to files and will
       allow only publically readable files to be accessed. Files may be
       written only if they already exist and are publically writable.

       Impact is evident, directory exported via TFTP must not contain
       sensitive information of any kind, everyone is allowed to read it as
       soon as a client is allowed. Boot images do not contain such
       information as rule, however you should think twice before publishing
       f.e. Cisco IOS config files via TFTP, they contain unencrypted
       passwords and may contain some information about the network, which
       you were not going to make public.

       The tftpd server should be executed by inetd with dropped root
       privileges, namely with a user ID giving minimal access to files
       published in tftp directory. If it is executed as superuser
       occasionally, tftpd drops its UID and GID to 65534, which is most
       likely not the thing which you expect. However, this is not very
       essential; remember, only files accessible for everyone can be read
       or written via TFTP.

SEE ALSO         top

       rarpd(8), tftp(1), inetd(8).

HISTORY         top

       The tftpd command appeared in 4.2BSD. The source in iputils is
       cleaned up both syntactically (ANSIized) and semantically (UDP socket
       IO).

       It is distributed with iputils mostly as good demo of an interesting
       feature (MSG_CONFIRM) allowing to boot long images by dumb clients
       not answering ARP requests until they are finally booted. However,
       this is full functional and can be used in production.

AVAILABILITY         top

       tftpd is part of iputils package.

COLOPHON         top

       This page is part of the iputils (IP utilities) project.  Information
       about the project can be found at ⟨http://www.skbuff.net/iputils/⟩.
       If you have a bug report for this manual page, send it to
       yoshfuji@skbuff.net, netdev@vger.kernel.org.  This page was obtained
       from the project's upstream Git repository 
       ⟨https://github.com/iputils/iputils.git⟩ on 2017-09-15.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

iputils s20161105                                                   TFTPD(8)

Pages that refer to this page: rarpd(8)