NFS Mount Authentication errors

["Chiu, PCM (Peter) " <P C M Chiu rl ac uk>]

Hi,

I have come across a problem in exporting RH ext2 file systems to
Compaq Alpha Tru64 Unix, and wonder if anyone can shed some
light on this.

The Linux box is running RedHat Release 7 (Kernel 2.2.16-22smp),
and the Alpha is on Tru64 Unix V4.0F.

The linux box has this in the /etc/exports:
/home host1(rw,no_auth_nlm,no_subtree_check,no_root_squash,sync)  host2

where /home is a local ext2 file system on the Redhat box, 
and host1 is the Alpha Tru64 Unix system.

Using the root account on host1, I can mount the /home ext2 file system and
access (write and read) the file systems okay.

However, normal users on host1 cannot access (eg. cd or ls ) /home, with
errors:
NFS2 getattr failed for server rain: RPC: authentication error

I need to add that both systems are sharing the same NIS (YP) with that,
users can log on (telnet) okay on both systems. They can also read and write
in the /home area.

I tried to mount the /home ext2 file system on host1 using NFS V3 option,
but the Redhat box is not supporting it.  (rpcinfo -p rain shows only V2 udp
nfs, making the client mount command to give RPC Programme not registered
errors).

Is NFS V3 needed to enable proper authentication between the two platforms?

If so, how to enable NFS V3 on the nfs kernel?  

rpm reveals nfs-utils 0.1.9.1 is in use.

Thanks in advance for any advice given.

Regards,
Peter Chiu
Rutherford Appleton Laboratory
Tel:  +44-(0)1235-446699
Fax: +44-(0)1235-445848
Email: P.Chiu@rl.ac.uk