When a mount request is sent to a server for an export that does not exist, the error message shown in the example below appears.

AIX NFS mounting error 1:

# mount nas500:/nasnfs /nas
mount: 1831-011 access denied for nas500:/nasnfs
mount: 1831-008 giving up on:
nas500:/nasnfs
The file access permissions do not allow the specified action.

Then you must check if the directory you want to mount is actually exported on the NAS Gateway 500. To check what file systems, directories, or files are exported from NAS Gateway 500, use the showmount command as follows:

showmount -e <IP address of NAS Gateway 500>

The output from the command shows you the directories exported, and to whom they are exported.

If NAS Gateway 500 doesn’t respond to the showmount command, or the error shown in following example is reported, you should check if the NFS server daemons are running at NAS Gateway 500.

AIX RPC error:

RPC: 1832-019 Program not registered

Use this command:
rpcinfo -p <IP address of NAS Gateway 500>

The following example shows the output you will get from this command.

rpcinfo on AIX:

# rpcinfo -p 9.1.38.198
program vers proto port service
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100021 1 udp 32772 nlockmgr
100021 2 udp 32772 nlockmgr
100021 3 udp 32772 nlockmgr
100021 4 udp 32772 nlockmgr
100021 1 tcp 32773 nlockmgr
100021 2 tcp 32773 nlockmgr
100021 3 tcp 32773 nlockmgr
100021 4 tcp 32773 nlockmgr
100024 1 tcp 32789 status
100024 1 udp 32798 status
100133 1 tcp 32789
100133 1 udp 32798
200001 1 tcp 32789
200001 1 udp 32798
200001 2 tcp 32789
200001 2 udp 32798

The output shows that the portmap (program 100000) is available, but statd (100024), lockd (100021), nfsd (100003), and mountd (100005) are not available. This means the NFS server is not up and running. You must review the NFS exports configuration steps introduced in the beginning of this chapter. Make sure there is no error generated when you make or modify NFS exports.

The reverse lookup problem on AIX
Sometimes you mount an NFS share through the SMIT menu or command line and get the error message shown in the following example.

AIX NFS mounting error 2:

# mount nas500:/home /mnt
nfsmnthelp: 1831-019 nas500: System call error number -1.
mount: 1831-008 giving up on:
nas500:/home
System call error number -1.

This is usually caused by the reverse lookup problem, which means NAS Gateway 500 can not resolve AIX client’s IP address to host name.

There are several ways for the NAS Gateway 500 to make the IP address to host name resolution. The most widely used methods in the TCP/IP world are DNS system and local file mapping. For availability reasons, we highly recommend that you use local file mapping, that is, store host to IP address mapping in the /etc/hosts file on NAS Gateway 500. We just do not want a DNS server outage to bring down the storage system.

Next we explain how to manage the local mapping on NAS Gateway 500.

First of all, you need to build an interactive session to the NAS Gateway 500, either through terminal or through telnet.

1. Login as root user. Run the command smitty hostent.
2. You will get the smitty Hosts table (/etc/hosts) screen.
   
3. You can add, remove, and modify local IP addresses to host name mapping entries here. You select the Add a host task and provide the next host information.The other functions of this menu are also very straightforward

Check the syntax on the mount command
Try to use SMIT menus while mounting a NFS share on AIX instead of long and complex command line entries, this can help you avoid a lot of errors.

Important: Always remember that only root can issue any mount command, and system group members can issue mounts, provided they have write access to the mount point.