showmount -e <host> is failing with "clnt_create: RPC: Port mapper failure - Timed out" or "Authentication error" on Red Hat Enterprise Linux 6

Issue

• A showmount command returns this error . We are able to successfully mount NFS shares from this filer though. This is on a system running RHEL6

$ showmount -e <NFS Server>
clnt_create: RPC: Port mapper failure - Timed out

$ showmount -e <NFS Server>
clnt_create: RPC: Port mapper failure - Authentication error



- On a system running RHEL4 it works

$ sudo /usr/sbin/showmount -e <NFS server>
Export list for <NFS Server>:
.
.
.