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 exports(4)							  exports(4)




 NAME
      exports, xtab - directories to export to NFS clients

 SYNOPSIS
      /etc/exports

      /etc/xtab

 DESCRIPTION
      File /etc/exports describes the directories that can be exported to
      NFS clients.  The system administrator creates it using a text editor.
      mountd processes it each time a mount request is received (see
      mountd(1M)).

      /etc/exports is read automatically by the exportfs command (see
      exportfs(1M)).  If this file is changed, exportfs must be run
      (exportfs -a) before the changes can affect the daemon's operation.

      If this file is present at boot time, the /sbin/init.d/nfs.server
      script will execute an exportfs command and export the file systems
      listed in the file.

      /etc/xtab contains entries for directories that are currently
      exported.	 This file should only be accessed by programs using
      getexportent (see exportent(3N)).	 (Use exportfs -u to remove entries
      from this file).

      An entry for a directory consists of a command line of the following
      form:

	   directory - option[, option]...

      where directory is the path name of a directory (or file).

      options can have any of the following values and forms:

	   ro	     Export the directory read-only.  If not specified, the
		     directory is exported read-write.	The ro and rw
		     options cannot be used on the same exports line.

	   rw=hostname[:hostname]...
		     Export the directory read-mostly.	Read-mostly means
		     read-only to most machines, but read-write to those
		     specified.	 If neither ro nor rw is specified, the
		     directory is exported read-write to all.  The ro and rw
		     options cannot be used on the same exports line.  Up to
		     256 hostnames can be specified.  With a server
		     configured for DNS naming in the nsswitch "hosts"
		     entry, any hostname must be represented as a fully
		     qualified DNS name.  Currently HP-UX will attempt to
		     match a non-fully qualified hostname; this HP-only



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 exports(4)							  exports(4)




		     feature will be obsoleted in a later release of HP-UX.

	   anon=uid  If a request comes from an unknown user, use uid as the
		     effective user ID.	 Note: Root users (uid 0) are always
		     considered ``unknown'' by the NFS server unless they
		     are included in the root option below.

		     The default value for this option is -2.  Setting anon
		     to -1 disables anonymous access.

	   root=hostname[:hostname]...
		     Give root access only to the root users from a
		     specified hostname.  The default is for no hosts to be
		     granted root access.  Up to 256 hostnames can be
		     specified.	 hostnames on this list are not guaranteed
		     to successfully mount the specified file system.  If a
		     non-empty access list is specified, the hostname must
		     also meet one of the access_list criteria described
		     below as well.  Up to 256 hostnames can be specified.
		     With a server configured for DNS naming in the nsswitch
		     "hosts" entry, any hostname must be represented as a
		     fully qualified DNS name.	Currently HP-UX will attempt
		     to match a non-fully qualified hostname; this HP-only
		     feature will be obsoleted in a later release of HP-UX.

	   access=[access_list][:access_list]...
		     Give mount access to each access_list listed.  See the
		     "access_list" subsection below.  An empty access= list
		     allows all machines to mount the specified mount point.

		     access_list
			  The access_list argument is a colon-separated list
			  whose components may be any number of the
			  following:

			  hostname
			       The name of a host.  With a server configured
			       for DNS naming in the nsswitch "hosts" entry,
			       any hostname must be represented as a fully
			       qualified DNS name.  Currently HP-UX will
			       allow a match for a non-fully qualified
			       hostname; this HP-only feature will be
			       obsoleted in a later release of HP-UX.

			  netgroup
			       A netgroup contains a number of hostnames.
			       With a server configured for DNS naming in
			       the nsswitch "hosts" entry, any hostname in a
			       netgroup must be represented as a fully
			       qualified DNS name.




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 exports(4)							  exports(4)




			  DNS suffix
			       To use domain membership the server must use
			       DNS to resolve hostnames to IP addresses;
			       that is, the "hosts" entry in the
			       /etc/nsswitch.conf must specify "dns" ahead
			       of "nis" or "nisplus", since only DNS returns
			       the full domain name of the host.  Other name
			       services like NIS or NIS+ cannot be used	 to
			       resolve hostnames on the server, because when
			       mapping an IP address to a hostname, they do
			       not return domain information.  For example,

			       NIS or NIS+

				  129.144.45.9 --> "myhost"

			       DNS

				  129.144.45.9 --> "myhost.myd.myc.com"

			       The DNS suffix is distinguished from
			       hostnames and netgroups by a prefixed dot.  A
			       dot by itself will match "myhost" but not
			       "myhost.myd.mycy.com".  This single dot
			       feature can be used to match hosts resolved
			       from NIS and NIS+ rather than DNS.

			  network
			       The network or subnet component is preceded
			       by an at-sign (@).  It can be either a name
			       or a dotted address.  If a name, it will be
			       converted to a dotted address by getnetbyname
			       (see getnetent(3N)).  Entries in
			       /etc/networks must contain all four octets in
			       order to be valid.

			       The network prefix assumes an octet aligned
			       netmask determined from the zero octets in
			       the low order part of the address.  In the
			       case where network prefixes are not byte-
			       aligned, the syntax will allow a mask length
			       to be specified explicitly following a slash
			       (/) delimiter.  Where the mask is the number
			       of leftmost contiguous significant bits in
			       the corresponding IP address.

			  -    A prefixed minus sign (-) denies access to
			       that component of access_list.  The list is
			       searched sequentially until a match is found
			       that either grants or denies access, or until
			       the end of the list is reached.	This option



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 exports(4)							  exports(4)




			       is valid only in conjunction with hostname,
			       network and DNS Suffix.	If prefixing a
			       hostname and you are configured for DNS
			       naming, you must fully qualify the hostname.

	   async     Specifying async increases write performance on the NFS
		     server by causing asynchronous writes on the NFS
		     server.  The async option can be specified anywhere on
		     the command line after directory.	Before using this
		     option, refer to WARNINGS below.

	   #	     A # character anywhere in the file indicates a comment
		     that extends to the end of the line.

	   A directory name with no accompanying name list allows any
	   machine to mount the given directory.

      /etc/exports contains a list of file systems and the access_lists or
      machine names allowed to remotely mount each file system.	 The file
      system names are left-justified and followed by a list of names
      separated by white space.	 A file system name with no accompanying
      name list means the file system is available to everyone.

      A # anywhere in the file indicates a comment extending to the end of
      that line.

 EXAMPLES
      /usr/games cocoa fudge		  # export to only these machines
      /usr	 -access=clients	  # export to my clients
      /usr/local			  # export to the world
      /usr2	 -access=bison:deer:pup	  # export to only these machines
      /var/adm	 -root=bison:deer	  # give root access only to these
      /usr/new	 -anon=0		  # give all machines root access
      /usr/temp	 -rw=ram:alligator	  # export read-write only to these
      /usr/bin	 -ro			  # export read-only to everyone
      /usr/stuff -access=bear,anon=-2,ro  # several options on one line
      /usr/subnet -access=@mysubnet    #use mysubent in /etc/networks
      /usr/subnet1 -access=@192.5	   #clients must be in the 192.5.0.0 subnet
      /usr/domain -access=.myd.myc.com #clients must be in .myd.myc.com
      /usr/restrict -access=-host1.myd.myc.com:sales # disallow -host1 in the sales netgroup.

 WARNINGS
      If the async option is used, an unreported data loss may occur ONLY on
      a write and ONLY if the NFS server experiences a failure after the
      write reply has been sent to the client.	Specifically, blocks which
      have been queued for the server's disk, but have not yet been written
      to the disk may be lost.

      You cannot export either a parent directory or a subdirectory of an
      exported directory that resides within the same file system.  It is
      not allowed, for instance, to export both /usr and /usr/local if both



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 exports(4)							  exports(4)




      directories reside on the same disk partition.

 AUTHOR
      exports was developed by Sun Microsystems, Inc.

 FILES
      /etc/exports	       Static export information

      /etc/xtab		       Current state of exported directories

      /etc/hosts	       List of hostnames

      /etc/netgroup	       List of network groups

      /etc/networks	       Network information

      /sbin/init.d/nfs.server  Script that executes exportfs command.

 SEE ALSO
      exportfs(1M), mountd(1M), nfsd(1M), exportent(3N), hosts(4),
      netgroup(4), networks(4)

































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