mknfsexp Command

Purpose

Exports a directory to NFS clients.

Syntax

/usr/sbin/mknfsexp -d Directory [ -e pathname] [ -f Exports_File ] [ -t [ { rw | ro | remove } { rm -h HostName [ , HostName ... ] } ] ] [ -a UID ] [ -r HostName [ , HostName ... ] ] [ -c HostName [ , HostName ... ] ] [ -s | -n ] [ -I | -B | -N ] [ -P | -p ] [ -D {yes | no} ] [ -v ] [ -x | -X ] [ -S flavor [ ,flavor ] ] [ -G rootpath@host[+host][:rootpath@host[+host]] ] [ -g rootpath@host[+host][:rootpath@host[+host]] ] [-o Ordering ]

Description

The mknfsexp command takes the flags and parameters specified and constructs a line that is syntactically correct for the /etc/exports file. If this command is invoked with the -B flag, an entry will be added to the /etc/exports file and the exportfs command is invoked to export the directory specified. Alternatively, the -I flag adds an entry to the exports file and does not export the directory, or the -N flag does not add an entry to the exports file but does export the directory.

Flags

Item	Description
-a UID	Uses the UID variable as the effective user ID only if a request comes from an unknown user. The default value of this option is -2. Note: Root users (UID 0) are always considered unknown by the NFS server, unless they are included in the root option. Setting the value of UID to -1 disables anonymous access.
-B	Adds an entry to the /etc/exports file and the exportfs command is executed to export the directory. This flag is the default.
-c HostName [ , HostName ] ...	Gives mount access to each of the clients listed. A client can either be a host or a netgroup. The default is to allow all hosts access.
-d Directory	Specifies the directory that is to be exported or changed.
-D {yes \| no}	Enables or disables file delegation for the specified export. This option overrides the system-wide delegation enablement for this export. The system-wide enablement is done through nfso.
-e pathname	Specifies an export name for the directory.
-f Exports_File	Specifies the full path name of the exports file to use if other than the /etc/exports file.
-g rootpath@host [+host] [:rootpath@host [+host]]	The specified directory will be marked with replica information. If the server becomes unreachable by an NFS client, the client can switch to one of the specified servers. This option is only accessible using NFS version 4 protocol, and version 4 access must be specified in the options. Because the directory is being exported for client access, specifying NFS version 2 or version 3 access will not cause an error, but the request will simply be ignored by the version 2 or version 3 server. This option cannot be specified with the -G flag. Only the host part of each specification is verified. The administrator must ensure that the specified rootpaths are valid and that the target servers contain appropriate data. If the directory being exported is not in the replica list, that directory will be added as the first replica location. The administrator should ensure that appropriate data exists at the replica locations. For a more complete description of replication, see the exportfs command. The -g option is available only on AIX® 5.3 with 5300-03 or later. Note: A referral or replica export can only be made if replication is enabled on the server. Use chnfs -R on to enable replication.
-G rootpath@host [+host] [:rootpath@host [+host]]	A namespace referral will be created at the specified path. The referral directs clients to the specified alternate locations where they can continue operations. A referral is a special object. If a nonreferral object exists at the specified path, the export is disallowed and an error message is printed. If nothing exists at the specified path, a referral object is created there that includes the path name directories leading to the object. A referral cannot be specified for the nfsroot. The name `localhost` cannot be used as a hostname. The -G option is allowed only for version 4 exports. If the export specification allows version 2 or version 3 access, an error message will be printed and the export will be disallowed. The administrator should ensure that appropriate data exists at the referral locations. For a more complete description of referrals, see the exportfs command. The -G option is available only on AIX 5L Version 5.3 with the 5300-03 Recommended Maintenance package or later. Note: A referral or replica export can only be made if replication is enabled on the server. Use chnfs -R on to enable replication.
-h HostName [ , HostName ] ...	Specifies which hosts have read-write access to the directory. This option is valid only when the exported file is to be read-mostly.
-I	Adds an entry to the /etc/exports file so that the next time the exportfs command is run during system restart, the directory will be exported.
-n	Does not require the client to use the more secure protocol. This flag is the default.
-N	Does not add an entry to the /etc/exports file but the exportfs command is run with the correct parameters so that the directory is exported.
-o Ordering	Defines how the alternate locations list is generated from the servers that you specified on the refer or replicas option. The option applies only to directories exported for access by NFS version 4 protocol. The Ordering parameter has three allowable values: full All of the servers are scattered to form the combinations of alternate locations. partial The first location of all the combinations is fixed to the first server specified on the refer or replicas option. The rest of the locations and the first location are scattered as if they are scattered using the `scatter=full` method. none No scatter is to be used. The value can also be used to disable scattering if it was enabled previously.
-p	Specifies that the exported directory is not a public directory.
-P	Specifies that the exported directory is to be a public directory.
-r HostName [ , HostName ] ...	Gives root users on the specified hosts access to the directory. The default is for no hosts to be granted root access.
-s	Requires clients to use a more secure protocol when accessing the directory.
-S flavor[,flavor]	May be used in conjunction with the -c, -t, or -r options to associate the option with one or more specific security methods. Most exportfs options can be clustered using the sec option. Any number of sec stanzas may be specified, but each security method can be specified only once. Allowable flavor values are: sys UNIX authentication. dh DES authentication. none Use the anonymous ID if it has a value other than `-1`. Otherwise, a weak auth error is returned. krb5 Kerberos. Authentication only. krb5i Kerberos. Authentication and integrity. krb5p Authentication, integrity, and privacy.
-t Type	Specifies whether the directory is read-write, read-only, or read-mostly. The possible values for the Type variable are: rw Exports the read-write directory. This is the system default. ro Exports the read-only directory. remove Removes the exported directory. rm Exports the read-mostly directory. If chosen, the -h flag must be used to specify the hosts that have read-write permission.
-v number [ , number ] ...	The directory specified by the -d option is made available to clients using the specified NFS versions. Valid values are 2, 3, or 4. You can export two entries for the same directory with different versions 2 (or 3) and 4.
-x	Accepts the replica location information specified with the -g option as-is. Does not insert the server's primary hostname into the list if it is not present. This flag is intended for use with servers with multiple network interfaces. If none of the server's host names are in the replica list, NFSv4 clients might treat the location information as faulty and discard it.
-X	Enables auto-insert of the primary hostname into the replica list. If the server's primary hostname is not specified in the replica list, the hostname will be added as the first replica location.

Examples

To export a directory with read-only permission, enter:
```
mknfsexp -d /usr -t ro
```
In this example, the mknfsexp command exports the /usr directory with read-only permission.
To export a directory with read-mostly permission and a secure protocol to specific hosts, enter:
```
mknfsexp -d /home/guest -t rm -h bighost,littlehost -s
```
In this example the mknfsexp command exports the /home/guest directory with read-mostly permission, using more secure protocol.
To export a directory with read-write permission to a specific netgroup and specific hosts, and to make the export effective on the next system restart, enter:
```
mknfsexp -d /usr -t rw -c host1,host3,grp3 -I 
```
In the above example, the mknfsexp command exports the /usr directory and gives read and write permission to host1, host2, and grp3. The -I flag makes this change effective on the next system restart.
To export a directory with read-only permission to an exports file other than /etc/exports, enter:
```
mknfsexp -d /usr -t ro -f /etc/exports.other
```
In the above example, the mknfsexp command exports the /usr directory with read-only permission to the /etc/exports.other file.
To export the /common/documents directory to allow access only to clients using NFS version 4 protocol, enter:
```
mknfsexp -d /common/documents -v 4
```
To export the /common/documents directory, allowing access to client1 and client2 for clients using krb5 access, enter:
```
mknfsexp -d /common/documents -S krb5 -r client1,client2
```
To export the /common/documents directory with full scattering for the hosts named s1 and s2 specified as referrals, enter the following command:
```
mknfsexp -d /common/documents -v 4 -G  /common/documents@s1:/common/
documents@s2 -o full
```
To export the /common/documents directory with partial scattering at hosts named s1, s2 and s3, specified as replicas, enter the following command:
```
mknfsexp  -d /common/documents -v 4 -g /common/documents@s1:/common/
documents@s2:/common/documents@s3 -o partial
```
To export the /common/documents directory with the export name /exports1/cool/mike, enter the following command:
```
mknfsexp -d /common/documents -e /exports1/cool/mike -S sys -v 4
```

Files

Item	Description
/etc/exports	Lists the directories that the server can export.

Security

Attention RBAC users and Trusted AIX users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.