in.tftpd (8)
Leading comments
Copyright (c) 1983, 1991 The Regents of the University of California. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following ...
NAME
tftpd - DARPA Trivial File Transfer Protocol serverSYNOPSIS
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.