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NBDTAB(5)							     NBDTAB(5)

       /usr/local/etc/nbdtab - configuration file for nbd-client


       This file allows	to configure predefined	connections for	nbd-client. It
       may contain multiple definitions, one per line, each of which  contains
       four space-separated fields.

       To  connect  a  device  specified in the	nbdtab file, run nbd-client(8)
       with the	short name of that device as the sole argument.	It  will  then
       look up the required information	in nbdtab, and make the	connection.

       Fields  are  separated  from  one another by any	number of space	or tab
       characters; records are separated from one another by  newline  charac-
       ters.  The  file	 may  also contain any number of comments, which start
       with a '#' character and	continue until the end of the line or the  end
       of the file, whichever is first.

       The file	contains the following fields:

       1. The  short  name  of the device file.	That is, it should contain the
	  name of the device without the leading /dev/ part;  e.g.,  it	 could
	  say nbd0.

       2. The  hostname	 (in  case  of a TCP socket) or	filename (in case of a
	  unix domain socket) on which the server is listening.

       3. The name of the export as exported by	nbd-server.

       4. Any extra options. This field	is optional  (no  pun  intended),  and
	  need	not  appear in a file if no options are	necessary. The options
	  recognized by	nbd-client(8) are specified below, in the section "Op-
	  tions".  Any unknown options in this field will produce a warning by
	  nbd-client, unless they are prepended	by an underscore ('_') charac-
	  ter;	the  underscore	is specifically	reserved for local use,	or for
	  distribution customization.

       Every command-line nbd-client option which allows to configure specific
       options	for a particular device	node has a corresponding option	in the
       nbdtab file, and	vice versa; where this isn't the case, that is a bug.

       Individual options in this field	should be separated from  one  another
       by the comma character.

       bs=block	size
	      The  block size for this export. If this option is not used, the
	      kernel's default will be used instead.

	      Corresponds to the -b option on the command line.

       cacertfile=certificate file
	      The CA certificate file for TLS. Corresponds to the -A option on
	      the command line.

       certfile=certificate file
	      The  certificate	file  for TLS. Corresponds to the -F option on
	      the command line.

	      The number of connections	to use for this	 device.   Corresponds
	      to the -C	option on the command line; see	nbd-client(8) for more
	      details on that option.

       keyfile=key file
	      The private key file for TLS. Corresponds	to the	-K  option  on
	      the command line.

	      Disable  the use of NBD_OPT_GO in	the conversation.  Corresponds
	      to the -g	option on the command line.

       port=port number
	      The port on which	to communicate with the	 nbd-server.  Defaults
	      to the IANA-assigned port	for NBD, 10809.

	      The timeout. If this option is not specified, no timeout is con-

	      Corresponds to the -t option on the command line.

	      Persist the connection, using the	semantics of the  -p  command-
	      line option.

       swap   Optimize for swap; -s.

       sdp    Use the Socket Direct protocol; -S.

       tlshostname=TLS hostname
	      The hostname for TLS purposes; -H

       unix   Use a Unix Domain	socket to connect to the server; -u.

       nbd-server (1), nbd-client (8), nbd-trdump (8)

       The  NBD	 kernel	 module	 and  the NBD tools were originally written by
       Pavel Machek (

       The  Linux  kernel  module  is  now   maintained	  by   Paul   Clements
       (,  while  the userland tools	are maintained
       by Wouter Verhelst (<>)

       On The Hurd there is a regular  translator  available  to  perform  the
       client side of the protocol, and	the use	of nbd-client is not required.
       Please see the relevant documentation for more information.

       This manual page	was written by Wouter Verhelst	(<>).
       Permission  is  granted to copy,	distribute and/or modify this document
       under the terms of the GNU General Public License, version 2,  as  pub-
       lished by the Free Software Foundation.

       A simple	nbdtab file could look like this:

       # swap space, called "swapexport" on the	server
       # optimize for swap, and	try to reconnect upon disconnect.
       nbd0 swapexport swap,persist
       # other export, called "data" on	the server. No options for this	one.
       nbd1 data

		: 2006-10-18 15:01:57 +0200 (wo, 18 okt	2006) $	     NBDTAB(5)


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