When mounting an NFS share from a Solaris 10 server, you may encounter the “RPC: Authentication” error. You may notice that you are able to mount the share via NFSv4, not not NFSv3. On the NFS server the /var/adm/messages may show the following errors for  the client:

rpcbind: [ID 702911 daemon.warning] refused connect from <IP> to getport()

Edit the “/etc/hosts.deny” file and comment out the line “ALL: ALL”. Here’s an example of the standard hosts.deny file on Solaris 10u6:

# Copyright (c) 2002 by Sun Microsystems, Inc.
# All rights reserved.
#
#ident  "@(#)hosts.deny 1.1     02/12/04     SMI"
#
# This file is supplied as part of the Solaris Security Toolkit and
# is used to deny access to specific services as part of the Solaris 9
# TCP Wrappers implementation.  This file should be customized based
# on individual site needs.
#
#ALL:   ALL

You may need to restart NFS server:

svcadm disable network/nfs/server ; svcadm enable network/nfs/server