xref: /freebsd/libexec/tftpd/tftpd.8 (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
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32.\"	@(#)tftpd.8	8.1 (Berkeley) 6/4/93
33.\"
34.Dd June 4, 1993
35.Dt TFTPD 8
36.Os BSD 4.2
37.Sh NAME
38.Nm tftpd
39.Nd
40Internet Trivial File Transfer Protocol server
41.Sh SYNOPSIS
42.Nm /usr/libexec/tftpd
43.Op Fl l
44.Op Fl n
45.Op Fl s Ar directory
46.Op Ar directory ...
47.Sh DESCRIPTION
48.Nm Tftpd
49is a server which supports the
50Internet Trivial File Transfer
51Protocol (\c
52.Tn RFC 783).
53The
54.Tn TFTP
55server operates
56at the port indicated in the
57.Ql tftp
58service description;
59see
60.Xr services 5 .
61The server is normally started by
62.Xr inetd 8 .
63.Pp
64The use of
65.Xr tftp 1
66does not require an account or password on the remote system.
67Due to the lack of authentication information,
68.Nm
69will allow only publicly readable files to be
70accessed.
71Files containing the string ``/\|\fB.\|.\fP\|/'' or starting with
72``\|\fB.\|.\fP\|/'' are not allowed.
73Files may be written only if they already exist and are publicly writable.
74Note that this extends the concept of
75.Dq public
76to include
77all users on all hosts that can be reached through the network;
78this may not be appropriate on all systems, and its implications
79should be considered before enabling tftp service.
80The server should have the user ID with the lowest possible privilege.
81.Pp
82Access to files may be restricted by invoking
83.Nm
84with a list of directories by including up to 20 pathnames
85as server program arguments in
86.Pa /etc/inetd.conf .
87In this case access is restricted to files whose
88names are prefixed by the one of the given directories.
89The given directories are also treated as a search path for
90relative filename requests.
91.Pp
92The chroot option provides additional security by restricting access
93of
94.Nm
95to only a chroot'd file system.  This is useful when moving
96from an OS that supported
97.Fl s
98as a boot server.  Because chroot is restricted to root, you must run
99.Nm
100as root.  However, if you chroot, then
101.Nm
102will set its user id to nobody.
103.Pp
104The options are:
105.Bl -tag -width Ds
106.It Fl l
107Log all requests using
108.Xr syslog 3
109with the facility of LOG_FTP.  Note: Logging of LOG_FTP messages
110will also need to be enabled in the syslog configuration file
111.Xr syslog.conf 5 .
112.It Fl n
113Suppress negative acknowledgement of requests for nonexistent
114relative filenames.
115.It Fl s Ar directory
116Cause
117.Nm
118to chroot to
119.Pa directory
120before accepting commands.  In addition, the user id is set to
121nobody.
122.Pp
123If you are not running
124.Fl s ,
125no user id change will be
126attempted.  You should not run
127.Nm
128as root unless you are using
129.Fl s .
130.El
131.Sh SEE ALSO
132.Xr tftp 1 ,
133.Xr inetd 8 ,
134.Xr syslogd 8
135.Sh HISTORY
136The
137.Nm
138command appeared in
139.Bx 4.2 .
140