using ipTables...

When my SBC target board (Linux 2.6) attempts to NFS mount a directory from
a Host system (Redhat Fedora 7) to its home directory the following
happens:

"ICMP: Destination unreachable (Host administratively prohibited)".

It seems that the Host PC's iptables rules are rejecting the target SBC's
request to do the NFS mount. Am I interpeting this right?

Oddly enough I can ping from the Host to the target SBC and back.


The documentation I've read regarding ipTables is fairly long and
comphrehensive. I will probably have to bite the bullet and read it 
but in the meantime is there anyone who has encountered this problem
and can they tell me what ipTables commands were used to make the
ipTables
honor the NFS request from the target SBC?

Cheers




Some background details:

I have a Host PC running Redhat Fedora7 and a target SBC board running
Linux 2.6. They are plugged into a switch (which in turn is connected to a

router). 

I am attempting to export using NFS the Host systems software development
directory to the SBC target board's home directory.

On the Host PC I did the following:
1) Configure the eht0 device to a static ip address, and
2) in /etc/export file I added a line to make the directory to be
exported
   visible to the target board

On the target board SBC I did the following:
1) in /etc/init.d/rcS add a line to make the host's exported directory 
appear under the /home directory on the target board.