NFS connections irregular

[Simon Slater]

	I have 3 computers A, B & C connected through an hub. B is a file
server running FC1, A & C have new installs of FC6. A & C can mount
shares on B.  However showmount -e gives:

# mount clntudp_create: RPC: Program not registered

from B to either of A or C; from C to A; A to C or itself.

	The mount -t nfs C:/share /mnt command from A returns:

# mount: mount to NFS server 'C' failed: System Error: No route to host.

similarly fron C to A.  Yet from server B the same command to either A
or C returns:

# mount: RPC: Remote system error - no route to host.

	Each box can ping the others, the /etc/hosts and /etc/exports files
seem to be in order.  What am I missing?

Regards 
Simon Slater