NFS

linux storage networking services

NFS (Network File System) allows sharing directories between Linux systems over a network. NFSv4 is the current recommended version and simplifies things by only requiring a single port (2049/tcp).

Server Setup

Install the NFS utilities (package name varies by distro: nfs-utils on Fedora/Arch, nfs-kernel-server on Debian/Ubuntu).

Define exports in /etc/exports:

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/srv/shared    10.0.0.0/24(rw,sync,no_subtree_check)
/srv/readonly  10.0.0.0/24(ro,sync,no_subtree_check)

Common export options:

rw / ro - Read-write or read-only access
sync - Write data to disk before replying (safer, slower)
no_subtree_check - Disables subtree checking, improves reliability
no_root_squash - Allows root on the client to act as root on the server (use cautiously)
root_squash - Maps root to nobody (default, more secure)

Apply changes and start the service:

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# exportfs -rv
# systemctl enable --now nfs-server

Verify what's being exported:

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$ exportfs -v

Client Setup

Install nfs-utils (or nfs-common on Debian/Ubuntu) on the client.

Mount an NFS share:

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# mount -t nfs4 server:/srv/shared /mnt/shared

For persistent mounts, add to /etc/fstab:

`1`	`server:/srv/shared /mnt/shared nfs4 defaults,_netdev 0 0`

The _netdev option tells the system to wait for network availability before attempting to mount.

Firewall

NFSv4 only needs port 2049/tcp. Older versions (v2/v3) require additional ports for rpcbind, mountd, and lockd which makes firewall configuration more complex. Stick with v4 if possible.

Troubleshooting

If the client gets a "wrong fs type" error, make sure nfs-utils is installed on the client side.

Check what a server is exporting from the client:

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$ showmount -e server

Debug mount issues with verbose output:

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# mount -t nfs4 -v server:/srv/shared /mnt/shared