Ubuntu uses UFW, which is extremely easy to configure, yet very potent, at least for soho needs.
So, the rpc.mountd listens on multiple ports by default thus you have to bind rpc.mountd to one port, then you can add an additional UFW rule to accept incoming connection on that particular port.
To do so, open /etc/default/nfs-kernel-server and comment out the line
and add the following line
13030 is just a randomly selected port, something that is available and isn’t already defined in /etc/services.
Restart NFSd with sudo /etc/init.d/nfs-server-kernel restart
Now configure the UFW to accept incoming connections on port 13030, 2049 and port 111.
ufw allow from 192.168.1.0/24 to any port 111 ufw allow from 192.168.1.0/24 to any port 2049 ufw allow from 192.168.1.0/24 to any port 13025
That’s it. You should now be able to mount your exports form another machine.