Provided by: atftpd_0.7.git20210915-4_amd64 bug

NAME

       atftpd - Trivial File Transfer Protocol Server.

SYNOPSIS

       atftpd [options] directory

DESCRIPTION

       atftpd  is a TFTP (RFC1350) server. By default it is started by inetd on most systems, 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
       specification.

OPTIONS

       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 100.

       -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).

       --trace
              When verbose level is set to 7, this will output debug information for each  packet
              sent or received from the network.

       --no-timeout
              disable 'timeout' from RFC2349. This will prevent the server from acknowledging the
              'timeout' option requested by the client.

       --no-tsize
              disable 'tsize' from RFC2349. This will prevent the server from  acknowledging  the
              'tsize' option requested by the client.

       --no-blksize
              disable 'blksize' from RFC2348. This will prevent the server from acknowledging the
              'blksize' request by the client.

       --no-windowsize
              disable 'windowsize' from RFC7440. This will prevent the server from  acknowledging
              the 'windowsize' request by the client.

       --no-multicast
              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).

       --pidfile
              Write  the  PID  of  the  server  to  the  specified  file. This may be useful when
              automatically starting and stopping one or more instance of the server.

       --daemon
              Run as a daemon. Do not use this option if atftpd is started by inetd.

       --no-fork
              When --daemon is specified, this option will prevent the  server  from  forking  to
              background. It is useful for debugging purpose or specialized usage.

       --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 getservbyname(3).

       --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 interfaces.

       --mcast-ttl
              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.

       --mcast-addr
              Specify the IP address range to be used for multicast transfer. Format  string  may
              comprise  range and list of values: "239.255.0.0-31,128-132,200".  Default value is
              "239.255.0.0-255". This address range is proposed in RFC2365 for local scope.

       --mcast-port
              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 allows one to replace requested
              file name based on Perl Compatible Regular Expression. See README.PCRE.

       --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 incoming request.

       --no-source-port-checking
              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.

       --prevent-sas
              Address  the  Sorcerer's  Apprentice  Syndrome  situation as requested by RFC 1350.
              This RFC requires repeated responses to a single packet  to  be  rejected.  Thus  a
              block  will  only  get retransmitted on a timeout.  For backward compatibility, the
              default stays to ignore this RFC.  So blocks get transmitted on every request.

       --mcast-switch-client
              This option allows 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,
              proceeding with the next one.

       -V, --version
              Show version of program.

       -h, --help
              Show summary of options.

       path   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.

STATS

       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.

SECURITY

       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.

PCRE

       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.

MTFTP

       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.

SEE ALSO

       inetd(8),hosts_access(5),libpcre(7),  RFC1350,  RFC2090,  RFC2347,  RFC2348,  RFC2349  and
       pxespec.pdf.

AUTHOR

       This  manual  page was written by Remi Lefebvre <remi@debian.org> and Jean-Pierre Lefebvre
       <helix@step.polymtl.ca>.

                                        December 27, 2000                               ATFTPD(8)