Title: NFS setup
Date: 2015-07-30
Lang: en

I'm planning to put my [Raspberry Pi](https://www.raspberrypi.org/) back to use. I have always disliked its dependency on SD memory cards so I'm planning to put the Pi's root filesystem on NFS. The Pi side will be a topic for another blog post later, first I'll have to setup an NFS server on my main [Gentoo](https://www.gentoo.org) machine.

The main NFS setup is described [on the Gentoo wiki](https://wiki.gentoo.org/wiki/NFS) in sufficient detail. I had a bit of a headache getting NFS through my [Shorewall](http://www.shorewall.net/) based firefall, though. There is a good section on NFS security in the [NFS-HOWTO](http://tldp.org/HOWTO/NFS-HOWTO/security.html) which describes all the necessary bits. And the Gentoo config files have all the required settings in their comments, too. It turns out that all you have to do is to put some configuration into place and the NFS server will play nicely with the firewall:

In `/etc/sysctl.conf` these settings:

    fs.nfs.nlm_tcpport = 4001
    fs.nfs.nlm_udpport = 4001

In `/etc/conf.d/nfs` enable these settings:

    OPTS_RPC_MOUNTD="-p 32767"
    OPTS_RPC_STATD="-p 32765 -o 32766"

Now all NFS daemons should be locked down to specific ports so you can add appropriate shorewall rules:

    ACCEPT    loc    fw    tcp    111  # portmapper
	ACCEPT    loc    fw    udp    111
	ACCEPT    loc    fw    tcp    2049 # rpc.nfsd
	ACCEPT    loc    fw    udp    2049
	ACCEPT    loc    fw    tcp    4001 # kernel lockd
	ACCEPT    loc    fw    udp    4001
	ACCEPT    loc    fw    tcp    32765:32767
	ACCEPT    loc    fw    udp    32765:32767

Restart the nfs service and the firewall. Now clients on the local network should be able to mount shares over NFS.