How to secure NFS?

[Dhananjay Balan]

Hi,

I am trying to run an NFS server following 
https://www.freebsd.org/doc/handbook/network-nfs.html (on 12.1-RELEASE-p6).

It doesn't touch at all about securing this server, is there any such 
documentation?

Also my pf never sees any of these packets. I have block in all on the 
file with explicit pass in rules and this just works :/ How is it 
completely by-passing my firewall?

Regards,
Dhananjay Balan