tftpd - DARPA Trivial File Transfer Protocol server
tftpd [-n] [-s] [directory ...]
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
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
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
-s All absolute filenames are treated as if they were preceded by
the first directory argument, or /tftpboot if there is none.
The tftpd command appeared in 4.2BSD.