How to Configure NFSv4 and NFSv3 on CentOS?

Installing an NFS file server on linux mainly consists of three short steps: install the NFS package, then configure (or in another words export) the NFS shares and lastly set the built-in firewall to allow incoming NFS queries.

1. Install NFS on CentOS

# The nfs-utils package contains the nfs server, also the client binaries
yum install -y nfs-utils

# Start and enable the NFS services
systemctl start nfs-server rpcbind
systemctl enable nfs-server rpcbind

2. Configure our NFS share

# Create the directory that will be exported as NFS share
mkdir /NFSShare

# Set read-write access for Everyone on it
chmod 777 /NFSShare

# Export the directory as NFS share, add the following line to the /exports file
vi /etc/exports

*:                     allow all hosts to connect to the share. If you want to specify different rules for different clients, simply create a separate line for each, using the IP address of the client instead of the asterisk character /NFSShare:     the shared directory that will be remotely accessible rw:                   writable permission to the folder sync:                all changes to the files are flushed immediately to disk. This makes the process a little slower, but more stable no_root_squash: root on the client machine will have root access on the NFS shared files instead of handled as user 'nobody'

# Re-export the NFS shares after editing the /etc/exports file
exportfs -r

3. Allow NFS on the server's firewall

NFSv4 uses only one port 2049/tcp that makes if easy to configure the firewall on the linux server. On the other hand, NFSv3 also needs 111 tcp and upd, and higher ports also be opened, to open them we issue the following commands:

# Firewall rules for NFSv4
firewall-cmd --permanent --add-service nfs
firewall-cmd --reload

# Firewall rules for NFSv3
firewall-cmd --permanent --add-service nfs
firewall-cmd --permanent --add-service mountd
firewall-cmd --permanent --add-service rpc-bind
firewall-cmd --reload

4. Connect to the share from a client

# Mount the NFS share using nfs version 4 (default)
[root@client ~]# mount -t nfs -o vers=4 10.0.1.200:/NFSShare /NFSmounted

# Mount the NFS share using nfs version 3 (older, but required by legacy systems)
[root@client ~]# mount -t nfs -o vers=3 10.0.1.200:/NFSShare /NFSmounted