nfs> server status
nfs> share show
network> ip addr show
network> ip route show

while mounting from the client, collect ethereal traces from filestore nodes using
# tethereal -i any -w /tmp/nfs_node01.trace port 2049 or port 4001 or port 111 and host not 127.0.0.1

Once verification is done to ensure mounts from internal network are successful, from the client try telnet to filestore

# telnet 217.27.88.119 111
# telnet 217.27.88.119 2049
# telnet 217.27.88.119 4001

Ports that need to be opened are:

2049 nfs (core nfs protocol)
4001 mountd
4045 NLM (NFS locking protocol)
portmappper is run on 111
Both TCP and UDP ports on 111,2049,4001,4045

Note Due to the way nfs works on Linux you might also need to add the insecure option to any volumes you export on certain clients.

On filestore the default nfs share option is 'secure' this means it will use ports in reserved port range (less than 1024). if insecure is set - then it can use ports outside that range.