atftpd - Trivial File Transfer Protocol Server.
is a TFTP (RFC1350) server. By default it is started by inetd on
most sytems, but may run as a stand alone daemon. This server is
multi-threaded and supports all options described in RFC2347 (option
extension), RFC2348 (blksize), RFC2349 (tsize and timeout) and RFC2090
(multicast option). It also supports mtftp as defined in the PXE
This program supports both the usual GNU command line syntax, with long options
starting with two dashes ('-') as well as short options. A description of the
options is included below.
- -t, --tftpd-timeout <value>
- Number of seconds of inactivity before the server exits.
This value has meaning only when the server is started by inetd. In daemon
mode, the server never exits. Default is 300 seconds.
- -r, --retry-timeout <value>
- How many seconds to wait for a reply before retransmitting
a packet. Default is 5 seconds. This can be overridden by the TFTP client
with the 'timeout' option.
- -m, --maxthread <value>
- Maximum number of concurrent threads allowed. Default is
- -v, --verbose[=value]
- Increase or set the logging level. No arguments will
increase by one the current value. Default is LOG_NOTICE, see syslog(3)
for log level. Valid value range from 0 (LOG_EMERG) to 7 (LOG_DEBUG).
- When verbose level is set to 7, this will output debug
information for each packet sent or received from the network.
- disable 'timeout' from RFC2349. This will prevent the
server from acknowledging the 'timeout' option requested by the client.
- disable 'tsize' from RFC2349. This will prevent the server
from acknowledging the 'tsize' option requested by the client.
- disable 'blksize' from RFC2348. This will prevent the
server from acknowledging the 'blksize' request by the client.
- disable 'multicast' from RFC2090. This will prevent the
server from acknowledging the 'multicast' request by the client.
- --logfile <logfile>
- Log to a specific file instead of only syslog. 'nobody' (or
any user used to run the server) must have permissions on the given file.
Assuming the file is /var/log/atftpd.log, simply run: "touch
/var/log/atftpd.log" and then "chown nobody.nogroup
/var/log/atftpd.log". When the server is run in daemon mode,
/dev/stdout or /dev/stderr can be used. Specifying a single dash as the
filename will send logs to stdout (file descriptor 1).
- Write the PID of the server to the specified file. This may
be useful when automatically starting and stopping one or more instance of
- Run as a daemon. Do not use this option if atftpd is
started by inetd.
- When --daemon is specified, this option will prevent the
server from forking to background. It is useful for debugging purpose or
- --user <user[.group]>
- By default, the server change identity to the user nobody
and group nogroup. Specify an alternate user.group with this option.
- --group <group>
- Alternate way of specifying the group. If group is
specified with --user and --group, the last option will be used.
- --port <number>
- Specify the port on which atftpd listens. Useful when
--daemon is specified. Default is standard tftp port as determined by
- --bind-address <IP address>
- Specify the IP address which atftpd binds to. Useful when
--daemon is specified. Default is to bind to all interfaces. Only one
address can be specified, the server can only listen to one or all
- Specify the TTL to be used for multicast datagram. By
default a value of 1 is used. Note that TTL has a special meaning in
multicast as it is used to determine the scope of the packets. The value
of 1 means the packets don't leave the local network, see ip(4). Scope may
also be determine by the address as described RFC2365.
- Specify the IP address range to be used for multicast
transfer. Format string may comprise range and list of values:
"126.96.36.199-31,128-132,200". Default value is
"188.8.131.52-255". This address range is proposed in RFC2365 for
- Specify the UDP port to use for multicast transfer. Format
string may contain range and list of port number:
"1758-2000,8000-9000". default value is "1758".
- --pcre <file>
- Specify a pattern/replacement file to use. This allow to
replace requested file name based on Perl Compatible Regular Expression.
- --pcre-test <file>
- Test a pattern/replacement file. When using this option,
the server will not start as usual but just read file name from stdin and
printout the substitution.
- --mtftp <file>
- This will start a mtftp server thread for each valid entry
in the supplied file. See PXE specification for detail about mtftp. An
example file is provided in the source distribution.
- --mtftp-port <port>
- Port the mtftp server shall listen to for incomming
- In some specific cases of networks using load balancer or
other equipment performing NAT (network address translation), some needs
to disable source port checking because port number as been translated. If
you want to use this feature, you must know why you need it and the
implication. Be aware that this option violate the RFC1350. This option
has effect only for non-multicast transfer.
- This option allow the server to proceed with the next
multicast client as soon as the current client timeout. When the current
master client fails to send an acknowledge (ACK) to the server, the server
will send an option acknowledge (OACK) to the master client with the field
MC (master client) set to false and send an OACK to the next multicast
client with MC set to true. Without this option, the server will retry the
current master client up to 5 times and then mark it done, proceding with
the next one.
- -V, --version
- Show version of program.
- -h, --help
- Show summary of options.
- This is the root directory used by the TFTP server. All
requested files from a TFTP client must reside in this directory. If not
specified, the directory defaults to /tftpboot. Since atftpd run as the
nobody user, the permission of the directory must be set properly to allow
file reading and writing.
Starting with release 0.2, the server collects some statistics. Currently the
server compute system load, time between connections and some thread
statistics like number of file sent, received, number of abort... To see those
stats in the logs, you need to set --verbose=6 (LOG_NOTICE) or higher.
TFTP by itself has no provision for security. There is no user authentication
and TFTP clients get access to all files within the specified root directory
for which the server has permission.
Some level of security can be gained using atftp libwrap support. Adding proper
entry to /etc/hosts.allow and /etc/hosts.deny will restrict access to trusted
hosts. Daemon name to use in these files is in.tftpd.
The atftpd server provides a way to dynamically replace requested file name by a
new one based on Perl compatible regular expression. Pairs of
pattern/replacement are read from the specified files. Upon reception of a
read request, the server will first try to open the file name requested. If it
fails, then it will search for a replacement based on the content of the
pattern file. If this still fails, then an error will be sent to the client.
This feature is available only for read request. It makes no sense doing this
substitution for client writing files to the server.
The mtftp name refer to multicasrt tftp as define by the PXE specification. See
pxespec.txt for the source of the specification. Note that this is not the
same as RFC2090. PXE compliant boot implements mtftp, not RFC2090.
(7), RFC1350, RFC2090,
RFC2347, RFC2348, RFC2349 and pxespec.pdf.
This manual page was written by Remi Lefebvre <email@example.com> and
Jean-Pierre Lefebvre <firstname.lastname@example.org>.