Trouble mounting an NFS share

[Robert Latest <boblatest@googlemail.com>]

Hello all,

I'm trying to mount an external NFS share on a Debian box. I must
admit that the server is not a Debian system but a D-Link DNS-323 NAS
running Linux. I think the problem is on the server side. (I've set up
an NFS server on the localhost as well for testing, and it works
fine.) What could be wrong here? Where should I check?

Regards,
robert

On the server:
/ # cat /etc/exports
/mnt/HD_b2 *(rw)
/ #

on the client:
client:/# rpcinfo -p 192.168.1.2
   program vers proto   port
    100000    2   tcp    111  portmapper
    100000    2   udp    111  portmapper
    100024    1   udp   1024  status
    100024    1   tcp   1025  status
    100005    1   udp   1025  mountd
    100005    1   tcp   1026  mountd
    100005    2   udp   1025  mountd
    100005    2   tcp   1026  mountd
    100005    3   udp   1025  mountd
    100005    3   tcp   1026  mountd
client:/# showmount -e 192.168.1.2
Export list for 192.168.1.2:
/mnt/HD_b2 *
client:/# mount -v -t nfs 192.168.1.2:/mnt/HD_b2 /mnt
mount.nfs: timeout set for Mon Jun 28 21:53:10 2010
mount.nfs: trying text-based options
'vers=4,addr=192.168.1.2,clientaddr=192.168.1.11'
mount.nfs: mount(2): Input/output error
mount.nfs: mount system call failed

(the last two lines appear after several minutes).