PC-NFS

AIX Version 4.3 System Management Guide: Communications and Networks

PC-NFS

PC-NFS is a program for personal computers that enables the personal computer to mount file systems exported by a Network File System (NFS) server. The personal computer can also request network addresses and host names from the NFS server. Additionally, if the NFS server is running the rpc.pcnfsd daemon, the personal computer can access authentication and print-spooling services.

You may want to configure the rpc.pcnfsd daemon on the following:

Systems that perform user authentication services
Systems that offer print-spooling
All Network Information Service (NIS) master and slave servers.

Note: Because NIS networks are typically configured so that PC-NFS can pick any NIS server as the default server, it is important that all servers have the rpc.pcnfsd program running. If running this program on all NIS servers is not practical, or if you want to limit requests to a specific server, add a net pcnfsd command to the autoexec.bat file on each personal computer to force it to use a specific NIS server.

PC-NFS Authentication Service

By default, PC-NFS presents itself to NFS servers as the nobody user. With nobody privileges, all personal computer user files appear as owned by nobody, and consequently you cannot distinguish between different personal computer users. The authentication capability of the rpc.pcnfsd daemon allow you to monitor system resources and security by recognizing individual users and assigning them different privileges.

With the rpc.pcnfsd daemon running, a PC-NFS user can issue the net name command from a personal computer to log in to PC-NFS in the same manner as a user can log in to AIX. The user's name and password are verified by the rpc.pcnfsd daemon. This authentication procedure does not make a server more secure, but it does provide more control over access to files that are available through NFS.

PC-NFS Print-Spooling Service

The print-spooling service of the rpc.pcnfsd daemon enables personal computers running PC-NFS to print to printers not directly attached to the personal computer. Specifically, PC-NFS redirects files intended for personal computer printers to a file on an NFS server. This file is placed in a spool directory on the NFS server. The rpc.pcnfsd daemon then invokes the server's printing facility. (The spooling directory must be in an exported file system so that PC-NFS clients can mount it.) When PC-NFS requests that the rpc.pcnfsd daemon print the file, it provides the following information:

Name of the file to be printed
Login ID of the user on the client
Name of the printer to be used.

Configuring the rpc.pcnfsd Daemon

To configure the rpc.pcnfsd daemon:

Install PC-NFS program on your personal computer.
Select a location for the spool directory on the NFS server. The default spool directory is /var/tmp. The spool directory must have at least 100K bytes of free space.
Export the spool directory. Do not put access restrictions on the exported directory that could cause access problems in your network. For details of this procedure, see "Exporting an NFS File System".
Start the rpc.pcnfsd daemon by following the instructions in "Starting the rpc.pcnfsd Daemon".
Verify that the rpc.pcnfsd daemon is accessible by following the instructions in "Verifying the rpc.pcnfsd Daemon Is Accessible".

Note: Because printer-redirection requests sometimes cause file listings of zero length to be left in the PC-NFS spool directories, you should periodically clear spooling directories of these entries.

Starting the rpc.pcnfsd Daemon

To start the rpc.pcnfsd daemon using the default spooling directory:

Using your favorite text editor, uncomment the following entry in the /etc/inetd.conf file:
```
pcnfsd sunrpc_udp udp wait root /usr/sbin/rpc.pcnfsd pcnfsd 150001 1
```
Save the file and exit the text editor.

To start the rpc.pcnfsd daemon using a directory different from the default:

Using your favorite text editor, add the following entry to the /etc/rc.nfs file:
```
if [ -f /usr/sbin/rpc.pcnfsd ] ; then
/usr/sbin/rpc.pcnfsd -s spooldir ; echo ' rpc.pcnfsd\c'
fi
```
where spooldir specifies the full path name of the spool directory.
Save the file and exit the text editor.
Using your favorite text editor, comment the following entry in the /etc/inetd.conf file:
```
pcnfsd sunrpc_udp udp wait root /usr/sbin/rpc.pcnfsd pcnfsd 150001 1
```
by placing a pound sign (#) at the beginning of the line. This prevents the inetd daemon from starting the rpc.pcnfsd daemon using the default spool directory.
Start the rpc.pcnfsd daemon print spooler by entering the following at the command line:
```
/usr/sbin/rpc.pcnfsd -s spooldir
```
where spooldir specifies the full path name of the spool directory.

For more information on updating the inetd configuration database, see "Configuring the inetd Daemon".

Note: The default directory that the rpc.pcnfsd daemon uses cannot be changed from the inetd.conf file.

Verifying the rpc.pcnfsd Daemon Is Accessible

To verify that the rpc.pcnfsd daemon is accessible, enter:

rpcinfo -u host 150001

where host specifies the host name of the system on which you are configuring rpc.pcnfsd, and 15001 is the RPC program number of the rpc.pcnfsd daemon. After you enter the command, you should receive the message that the program is ready and waiting.