Setup an NFS File Share

sudo apt install nfs-kernel-server nfs-common -y

Edit this file…

sudo nano /etc/exports

Add the following to the end of the file…

/mnt/HDD 10.10.10.0/24(rw,sync,no_subtree_check,crossmnt,no_root_squash)

Make sure to change the mountpoint and accessible IP range

Restart the NFS Service…

sudo service nfs-kernel-server restart

/mnt/HDD is the folder/directory you want to share
10.10.10.0/24 is the IP range you want this share to be accessible from. Note, you can also share individual IP addresses in the format 10.10.10.5
rw means the share will have read and write privileges. If you want read only privileges then you would use ro
sync means that all changes to the share are immediately flushed to disk
no_subtree_check means that you will also gain access to any subfolders within /mnt/HDD

To mount this on a Linux system, add this to the file /etc/fstab ensuring that you have the package nfs-common installed

ip-of-nfs-server:/mnt/HDD /mountpoint/ nfs rw 0 0