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NFS-Kernel Server : Linux File Sharing Configuration

A detailed guide to configuring and managing NFS-Kernel Server, covering installation, commands, troubleshooting, and best practices for Linux.

Understanding NFS-Kernel Server

The NFS (Network File System) Kernel Server is a critical component in Unix/Linux environments that allows file sharing between systems on a network. Developed by Sun Microsystems in the 1980s, NFS enables a client machine to access files on a remote server as though they were local. This capability makes it an essential tool for managing resources in both small and large-scale deployments.

Key features include:

  • File Sharing: Share directories and files across multiple systems.
  • Centralized Management: Manage files in a central location, reducing redundancy.
  • Cross-Platform Compatibility: Interoperate between different Unix-like systems.
  • User Mapping: Map remote users to local users for secure access control.

A detailed guide to configuring and managing NFS-Kernel Server, covering installation, commands, troubleshooting, and best practices for Linux.

Installation and Configuration

Prerequisites

Before starting, ensure:

  • A Linux server (e.g., Ubuntu, CentOS) for hosting NFS.
  • A client machine (Linux or Unix-based).
  • Administrative privileges on both systems.
  • Basic understanding of file permissions.

Installing NFS-Kernel Server

On Ubuntu/Debian:

sudo apt update
sudo apt install nfs-kernel-server -y

On CentOS/RHEL:

sudo yum update
sudo yum install nfs-utils -y

Configuring NFS Exports

Edit the /etc/exports file to define shared directories and access permissions. Example configuration:

/home/shared 192.168.1.0/24(rw,sync,no_subtree_check)

Explanation of options:

  • /home/shared: Directory to be shared.
  • 192.168.1.0/24: Restricts access to a specific subnet.
  • rw: Grants read-write access.
  • sync: Ensures data is written to disk before confirming.
  • no_subtree_check: Prevents subtree-related permission issues.

Applying Changes

sudo exportfs -a

Starting and Enabling NFS Service

sudo systemctl start nfs-kernel-server
sudo systemctl enable nfs-kernel-server

Configuring the Firewall

Allow NFS traffic through the firewall:

sudo ufw allow from 192.168.1.0/24 to any port nfs

Client-Side Configuration

Installing the NFS Client

On Ubuntu/Debian:

sudo apt install nfs-common -y

On CentOS/RHEL:

sudo yum install nfs-utils -y

Mounting an NFS Share

sudo mount -t nfs 192.168.1.100:/home/shared /mnt

Automating Mounts with /etc/fstab

192.168.1.100:/home/shared /mnt nfs defaults 0 0

Common Commands for NFS Management

Listing Active Exports

sudo exportfs -v

Restarting the NFS Service

sudo systemctl restart nfs-kernel-server

Troubleshooting NFS

Permissions Issues

sudo chmod 777 /home/shared

Firewall Blocks

sudo ufw allow from <client-ip> to any port nfs

Client Cannot Mount

sudo showmount -e 192.168.1.100

Best Practices

  • Use firewall rules and IP restrictions to enhance security.
  • Implement UID/GID mapping for proper user management.
  • Regularly monitor logs for suspicious activity.