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in.tftpd(8)


NAME

     tftpd — DARPA Trivial File Transfer Protocol server

SYNOPSIS

     tftpd [-n] [-s] [directory ...]

DESCRIPTION

     Tftpd is a server which supports the DARPA Trivial File Transfer
     Protocol.  The TFTP server operates at the port indicated in the ‘tftp’
     service description; see services(5).  The server is normally started by
     inetd(8).

     The use of tftp(1) does not require an account or password on the remote
     system.  Due to the lack of authentication information, tftpd will allow
     only publicly readable files to be accessed.  Files may be written only
     if they already exist and are publicly writable.  Note that this extends
     the concept of “public” to include all users on all hosts that can be
     reached through the network; this may not be appropriate on all systems,
     and its implications should be considered before enabling tftp service.
     The server should have the user ID with the lowest possible privilege.

     Access to files may be controlled by invoking tftpd with a list of
     directories by including pathnames as server program arguments in
     /etc/inetd.conf.  In this case access is restricted to files whose names
     are prefixed by the one of the given directories. If no directories are
     supplied the default is /tftpboot.  To give out access to the whole
     filesystem, should this be desired for some reason, supply / as an
     argument.

     Unfortunately, on multi-homed systems, it is impossible for tftpd to
     determine the address on which a packet was received. As a result, tftpd
     uses two different mechanisms to guess the best source address to use for
     replies. If the socket that inetd(8) passed to tftpd is bound to a
     particular address, tftpd uses that address for replies. Otherwise, tftpd
     uses ``UDP connect'' to let the kernel choose the reply address based on
     the destination of the replies and the routing tables. This means that
     most setups will work transparently, while in cases where the reply
     address must be fixed, the virtual hosting feature of inetd(8) can be
     used to ensure that replies go out from the correct address.  These
     considerations are important, because most tftp clients will reject reply
     packets that appear to come from an unexpected address.

     The options are:

     -n      Suppresses negative acknowledgement of requests for nonexistent
         relative filenames.

     -s      All absolute filenames are treated as if they were preceded by
         the first directory argument, or /tftpboot if there is none.

SEE ALSO

     tftp(1), inetd(8)

HISTORY

     The tftpd command appeared in 4.2BSD.



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