xref: /freebsd/libexec/tftpd/tftpd.8 (revision 20271f308fd29a493e50206d82941fc4aac841ab)

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.\"	@(#)tftpd.8	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt TFTPD 8
.Os BSD 4.2
.Sh NAME
.Nm tftpd
.Nd
Internet Trivial File Transfer Protocol server
.Sh SYNOPSIS
.Nm tftpd
.Op Fl l
.Op Fl n
.Op Fl s Ar directory
.Op Ar directory ...
.Sh DESCRIPTION
.Nm Tftpd
is a server which supports the
Internet Trivial File Transfer
Protocol (\c
.Tn RFC 783).
The
.Tn TFTP
server operates
at the port indicated in the
.Ql tftp
service description;
see
.Xr services 5 .
The server is normally started by
.Xr inetd 8 .
.Pp
The use of
.Xr tftp 1
does not require an account or password on the remote system.
Due to the lack of authentication information,
.Nm tftpd
will allow only publicly readable files to be
accessed.
Files containing the string ``/\|\fB.\|.\fP\|/'' or starting with
``\|\fB.\|.\fP\|/'' are not allowed.
Files may be written only if they already exist and are publicly writable.
Note that this extends the concept of
.Dq 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.
.Pp
Access to files may be restricted by invoking
.Nm tftpd
with a list of directories by including up to 20 pathnames
as server program arguments in
.Pa /etc/inetd.conf .
In this case access is restricted to files whose
names are prefixed by the one of the given directories.
The given directories are also treated as a search path for
relative filename requests.
.Pp
The chroot option provides additional security by restricting access
of tftpd to only a chroot'd file system.  This is useful when moving
from an OS that supported
.Nm -s
as a boot server.  Because chroot is restricted to root, you must run
tftpd as root.  However, if you chroot, then
.Nm tftpd
will set its user id to nobody.
.Pp
The options are:
.Bl -tag -width Ds
.It Fl l
Logs all requests using
.Xr syslog 3 .
.It Fl n
Suppresses negative acknowledgement of requests for nonexistent
relative filenames.
.It Fl s Ar directory
Causes tftpd to chroot to
.Pa directory
before accepting commands.  In addition, the user id is set to
nobody.
.Pp
If you are not running -s, no user id change will be
attempted.  You should not run tftpd as root unless you are using -s.
.El
.Sh SEE ALSO
.Xr tftp 1 ,
.Xr inetd 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .