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28 .\" @(#)tftpd.8 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/libexec/tftpd/tftpd.8,v 1.6.2.6 2003/04/06 19:42:56 dwmalone Exp $
31 .Dd September 14, 2000
36 .Nd Internet Trivial File Transfer Protocol server
38 .Nm /usr/libexec/tftpd
46 utility is a server which supports the
47 Internet Trivial File Transfer
53 at the port indicated in the
58 The server is normally started by
63 does not require an account or password on the remote system.
64 Due to the lack of authentication information,
66 will allow only publicly readable files to be
68 Files containing the string ``/\|\fB.\|.\fP\|/'' or starting with
69 ``\|\fB.\|.\fP\|/'' are not allowed.
70 Files may be written only if they already exist and are publicly writable.
71 Note that this extends the concept of
74 all users on all hosts that can be reached through the network;
75 this may not be appropriate on all systems, and its implications
76 should be considered before enabling tftp service.
77 The server should have the user ID with the lowest possible privilege.
79 Access to files may be restricted by invoking
81 with a list of directories by including up to 20 pathnames
82 as server program arguments in
84 In this case access is restricted to files whose
85 names are prefixed by one of the given directories.
86 The given directories are also treated as a search path for
87 relative filename requests.
91 option provides additional security by changing
93 root directory, thereby prohibiting accesses outside of the specified
97 requires super-user privileges,
100 However, after performing the
103 will set its user id to that of the specified
114 Changes the default root directory of a connecting host via chroot based on the
115 connecting IP address.
116 This prevents multiple clients from writing to the same file at the same time.
117 If the directory does not exist, the client connection is refused.
120 option is required for
128 except it falls back to
131 if a directory does not exist for the client's IP.
133 Log all requests using
140 must also be enabled in the syslog configuration file,
143 Suppress negative acknowledgement of requests for nonexistent
145 .It Fl s Ar directory
148 to change its root directory to
150 After changing roots but before accepting commands,
152 will switch credentials to an unprivileged user.
154 Switch credentials to
161 The user must be specified by name, not a numeric UID.
170 .%T The TFTP Protocol (Revision 2)
181 option was introduced in
185 option was introduced in
189 option was introduced in
192 Files larger than 33488896 octets (65535 blocks) cannot be transferred
193 without client and server supporting blocksize negotiation (RFC 1783).
195 Many tftp clients will not transfer files over 16744448 octets (32767 blocks).