How to Build a Secure File Server on Ubuntu Using Samba and NFS [Step-by-Step Guide]

By 佐川 直弘 | Naohiro Sagawa (運営者)

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1. Why Build a File Server with Ubuntu?

What is a File Server?

A file server is a server that allows multiple devices on a network to store and share files in a centralized location. It’s a great way to streamline file transfers within a home or office network and provides benefits such as centralized data management and simplified backups.

For example, if several people need to work on the same document, saving it on a file server ensures that everyone accesses the most up-to-date version, rather than passing around files on local PCs. It also reduces the risk of data loss compared to saving files on individual computers.

Why Use Ubuntu?

There are many operating systems you can use to build a file server, but Ubuntu is one of the most popular choices. Here’s why:

1. It’s Free to Use

Ubuntu is an open-source Linux distribution with zero licensing fees. This makes it an attractive option for individuals or businesses looking to set up a server environment on a budget.

2. Lightweight and Stable

Ubuntu uses minimal system resources and can run smoothly on older PCs or devices like Raspberry Pi. With Long-Term Support (LTS) versions, you’ll receive security updates and bug fixes for years—ideal for server use.

3. Rich Support for Tools Like Samba and NFS

Ubuntu supports popular file-sharing protocols like Samba (for sharing with Windows) and NFS (for Linux/Unix sharing) right out of the box. It has a wide selection of packages and documentation, making it beginner-friendly to set up.

4. Strong Community and Abundant Resources

Since Ubuntu is widely used around the world, it’s easy to find solutions online when problems arise. The extensive community support ensures you’re never stuck for long. Even non-English speakers can find helpful guides in various languages.

Ideal for Home and Small Office Use

Ubuntu-based file servers are perfect for sharing data between devices at home or for collaboration in small office or SOHO (Small Office/Home Office) environments. Compared to buying a NAS (Network Attached Storage), it offers more flexibility at a lower cost.

Here are a few common use cases:

• A media server to share photos and videos with family
• A shared workspace for invoices and quotes in a small business
• A collaborative space for code and documents within a dev team

2. Comparing File Sharing Methods: Samba vs NFS

When setting up a file server with Ubuntu, two main methods are commonly used: Samba and NFS. Both allow file sharing over a network, but they differ in the operating systems they support and their technical characteristics. In this section, we’ll compare both to help you choose the best one for your needs.

What is Samba? Excellent Compatibility with Windows

Samba is a software package that implements the SMB (Server Message Block) protocol, which is used by Windows for file sharing. By installing Samba on Ubuntu, you can build a file server accessible from Windows PCs as if it were a network drive.

Key Features of Samba

• High compatibility with Windows systems
• Easy access to shared folders from Windows Explorer
• Detailed control over user authentication and permissions
• GUI-based configuration tools (e.g., Webmin) available

When to Use Samba

• You want to share files with Windows clients
• You need to share files between different OSs (e.g., Windows and Linux)
• You want a user-friendly setup for home or office environments

What is NFS? Fast and Efficient Sharing for Linux/Unix

NFS (Network File System) is a file sharing protocol primarily used between Linux and Unix systems. From the client’s point of view, an NFS-shared folder appears like a local directory mounted on the system.

Key Features of NFS

• Ideal for sharing files between Linux systems
• Lightweight with fast transfer speeds
• Simple configuration supports large-scale sharing
• Requires careful security settings (IP-based access control)

When to Use NFS

• Server environments that share files between Linux machines
• Shared directories within a development team
• Scenarios requiring lightweight and high-speed transfers

Comparison Table: Samba vs NFS

Which One Should You Choose?

Ultimately, your choice depends on which OS you’re sharing files with, how you plan to use the server, and what your priorities are.

• Choose Samba if your main goal is to share files with Windows devices
• Choose NFS if you’re working in a Linux-to-Linux environment and need speed and simplicity
• If your environment includes both, consider using Samba and NFS together

Thanks to Ubuntu’s flexibility, you can easily set up both protocols and use them side by side depending on your needs.

3. [Samba Edition] How to Set Up a File Server on Ubuntu

In this section, we’ll walk you through how to set up a file server on Ubuntu using Samba, step by step. This method is especially useful if you want to share files with Windows PCs.

Preparation: Update Ubuntu and Check Packages

First, make sure your Ubuntu system is up to date. Open your terminal and run the following commands:

sudo apt update
sudo apt upgrade

Next, check if the necessary packages are installed, including Samba:

smbclient --version

If no version is displayed, proceed to install Samba in the next step.

Installing Samba

Use the following command to install the Samba package:

sudo apt install samba -y

After installation, check if the Samba service is active:

sudo systemctl status smbd

If it shows “active (running),” you’re good to go.

Editing smb.conf and Creating a Shared Folder

The Samba configuration file is located at /etc/samba/smb.conf. First, create the shared folder. In this example, we’ll use /srv/samba/shared as the directory to share:

sudo mkdir -p /srv/samba/shared
sudo chmod 777 /srv/samba/shared

Then edit the configuration file:

sudo nano /etc/samba/smb.conf

Add the following section to the end of the file:

[Shared]
   path = /srv/samba/shared
   browseable = yes
   read only = no
   guest ok = yes

This setup creates a public folder where anyone can read and write files. For added security, consider setting up user authentication (explained below).

To apply the changes, restart the Samba service:

sudo systemctl restart smbd

Creating a Samba User and Setting Access Permissions

To make the shared folder secure, it’s recommended to create a Samba user and restrict access.

1. Create a local Ubuntu user (skip this if the user already exists):

sudo adduser sambauser

2. Add the user to Samba:

sudo smbpasswd -a sambauser

3. Change folder ownership and restrict permissions:

sudo chown sambauser:sambauser /srv/samba/shared
sudo chmod 770 /srv/samba/shared

4. Update smb.conf to require authentication:

[SecureShared]
   path = /srv/samba/shared
   browseable = yes
   read only = no
   valid users = sambauser

How to Connect from a Windows Client

Once the Samba server is configured, you can connect to it from a Windows PC using the steps below:

1. Open Windows Explorer
2. In the address bar, type \\[Ubuntu server IP]\Shared
3. If prompted, enter the sambauser username and password you created

If the connection is successful, you’ll be able to read and write files just like with a regular folder.

4. [NFS Edition] How to Set Up a File Server on Ubuntu

NFS (Network File System) is a lightweight and high-speed network file sharing protocol widely used in Linux and Unix environments. It’s easy to implement on Ubuntu and enables smooth file sharing between multiple Linux machines.

In this section, we’ll walk through the steps to set up an NFS server on Ubuntu.

How to Install the NFS Server

First, install the NFS server package. On your Ubuntu server, run the following commands:

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

After installation, check if the NFS service is running:

sudo systemctl status nfs-server

If you see “active (running),” the installation was successful.

Configure /etc/exports and Define the Shared Directory

Next, create the directory you want to share with clients. In this example, we’ll use /srv/nfs/shared:

sudo mkdir -p /srv/nfs/shared
sudo chown nobody:nogroup /srv/nfs/shared
sudo chmod 755 /srv/nfs/shared

Then edit the NFS configuration file /etc/exports:

sudo nano /etc/exports

Add the following line (replace 192.168.1.0/24 with your actual network range):

/srv/nfs/shared 192.168.1.0/24(rw,sync,no_subtree_check)

To apply the changes, run the following commands:

sudo exportfs -a
sudo systemctl restart nfs-server

Your NFS server is now configured and ready to use.

Mounting the NFS Share on a Client (Linux)

On the client-side Linux machine, install the NFS client package:

sudo apt update
sudo apt install nfs-common -y

Create the directory where you want to mount the shared folder (e.g., /mnt/nfs_shared):

sudo mkdir -p /mnt/nfs_shared

Now mount the shared folder using the following command:

sudo mount -t nfs 192.168.1.10:/srv/nfs/shared /mnt/nfs_shared

*Replace 192.168.1.10 with the IP address of your NFS server.

This will make the NFS server’s shared folder accessible as a local directory on the client machine.

Optional: Auto-Mount on System Startup

If you want the NFS share to mount automatically at boot, add the following line to /etc/fstab:

192.168.1.10:/srv/nfs/shared /mnt/nfs_shared nfs defaults 0 0

This ensures the shared folder is mounted automatically each time the system starts.

NFS-Specific Access Restrictions and Considerations

Unlike Samba, NFS uses IP-based access control. In /etc/exports, always specify only trusted networks or hosts.

Also, if the UID (User ID) and GID (Group ID) between the client and server don’t match, ownership of files may not be recognized correctly. To avoid this issue, it’s ideal to keep the same UID and GID for users accessing shared folders on both systems.

With that, your Ubuntu NFS file server setup is complete. Compared to Samba, NFS is simpler and faster, making it an excellent option for Linux-to-Linux file sharing.

5. Security and Best Practices for File Server Management

File servers are incredibly useful for sharing data over a network, but without proper precautions, they can become vulnerable to data breaches and unauthorized access. In this section, we’ll go over the best security and management practices for running a file server on Ubuntu.

Restrict Access Using the Firewall (ufw)

Ubuntu includes a built-in firewall tool called ufw (Uncomplicated Firewall). When using Samba or NFS, make sure to explicitly open only the necessary ports to block unwanted traffic.

Example: Open Ports for Samba

sudo ufw allow Samba

This command opens all ports required for Samba (137, 138, 139, 445) with a single rule.

Example: Open Ports for NFS

NFS may use different ports depending on your setup, so you can open specific ones or configure them to be static. Here’s a common example:

sudo ufw allow from 192.168.1.0/24 to any port nfs

*192.168.1.0/24 represents the trusted network range.

Strengthening Access Control and User Authentication

Samba Access Restrictions

• Use valid users to specify which users can access each shared folder
• Set read only = yes to allow read-only access
• Use hosts allow or hosts deny to restrict access based on IP address

Example configuration in smb.conf:

[SecureShared]
   path = /srv/samba/secure
   read only = no
   valid users = user1
   hosts allow = 192.168.1.

NFS Access Restrictions

• Use /etc/exports to specify which IPs or networks can access each share
• Clearly define rw (read-write) or ro (read-only)
• Enable root_squash to restrict root access from clients

Example configuration:

/srv/nfs/secure 192.168.1.0/24(rw,sync,no_subtree_check,root_squash)

Monitor Logs and Detect Abnormal Activity

Monitoring logs is essential to detect unauthorized access or server errors.

• Samba logs: /var/log/samba/log.smbd
• NFS logs: /var/log/syslog or journalctl -u nfs-server

You can also use tools like fail2ban to block IPs after multiple failed login attempts automatically.

Set Up Automatic Backups

Accidental deletions or hardware failures can happen at any time, so automated regular backups are a must.

Examples of Backup Strategies

• Use rsync for incremental backups
• Automate with cron to schedule backups
• Store backups on an external HDD or NAS
• Sync with cloud storage (e.g., Google Drive, Dropbox) using tools like rclone

Example: Schedule a daily backup at 2 AM using rsync and cron

0 2 * * * rsync -a /srv/samba/shared/ /mnt/backup/shared/

Keep Software Up to Date

Keeping your system updated helps prevent vulnerabilities and maintain security.

sudo apt update && sudo apt upgrade -y

Also, using an Ubuntu Long Term Support (LTS) version ensures you receive security updates for an extended period.

Remember, managing a file server is not a “set it and forget it” task. To ensure it runs securely and smoothly, stay on top of security, backups, and maintenance as part of your regular operations.

6. Common Issues and How to Troubleshoot Them

Even after setting up your file server, you might encounter common issues or configuration mistakes. This section summarizes frequent problems with Ubuntu file servers using Samba or NFS and how to fix them.

Cannot Connect / Shared Folder Not Visible

Symptoms

• Unable to access shared folders from Windows or Linux clients
• The server does not appear on the network

Possible Causes and Solutions

Permission Errors

Symptoms

• Cannot create or edit files
• “Access denied” error appears

Possible Causes and Solutions

Mount Not Persistent / Share Disappears After Reboot

Symptoms

• Shared folder disappears after reboot on Linux clients
• Need to manually run the mount command every time

Possible Causes and Solutions

Example fstab entry for NFS:

192.168.1.10:/srv/nfs/shared /mnt/nfs_shared nfs defaults,_netdev,nofail 0 0

Files Not Visible / Changes Not Reflected

Symptoms

• Files saved from another client do not appear
• Changes are not updated immediately

Possible Causes and Solutions

Checking Logs and Diagnosing Issues

When diagnosing problems in Ubuntu, reviewing logs is extremely helpful.

Samba Logs

cat /var/log/samba/log.smbd

NFS Logs

journalctl -u nfs-server

Logs will show details such as access failures, authentication issues, or misconfigurations. You can often search error messages on Google to find solutions.

Tips for Effective Troubleshooting

• Make configuration changes one step at a time and test as you go
• Always back up config files before editing
• Use validation tools like testparm or exportfs -v
• After making changes, don’t forget to restart or reload services

7. FAQ: Frequently Asked Questions About Ubuntu File Servers

When building and managing a file server with Ubuntu, many users—especially beginners and intermediates—tend to have common questions and concerns. This section answers those frequently asked questions to help make your server setup and maintenance smoother.

Q1. Should I use Samba or NFS?

A. Choose based on the operating systems of your clients.

• If most of your clients use Windows, Samba (SMB) is the better option
  → Allows easy access through Windows File Explorer
• If you’re sharing files between Linux systems, go with NFS
  → It’s lightweight, fast, and stable

In mixed environments, you can run both Samba and NFS simultaneously. There’s no need to limit yourself to one if both are useful.

Q2. How do I share an external storage device like a USB HDD?

A. First, mount the external device, then set it as a shared folder.

1. Check connected devices:

lsblk

2. Create a mount point and mount the device:

sudo mkdir /mnt/usb
sudo mount /dev/sdX1 /mnt/usb

3. Then, configure Samba or NFS to share the /mnt/usb directory.

To mount the USB device automatically at boot, add an entry to /etc/fstab.

Q3. I can’t access the Samba server from Windows 11

A. It might be due to SMB protocol version or authentication settings.

Here’s how to fix it:

• Edit the Samba config file /etc/samba/smb.conf and add the following:

client min protocol = SMB2
server min protocol = SMB2

• Disable guest access and require login with a username and password
• If “SMB 1.0” is enabled in Windows, consider disabling it for better security

Q4. What’s the best way to back up my file server?

A. Automating regular backups is the best practice.

Recommended methods include:

• Incremental backups using rsync
• Scheduling with cron for automated execution
• Saving to external drives or NAS
• Syncing with cloud storage (e.g., Google Drive) using rclone

Example: Run a backup every night at 2 AM

0 2 * * * rsync -a /srv/samba/shared/ /mnt/backup/

Q5. Should I use Ubuntu Desktop or Ubuntu Server for my file server?

A. For stable, long-term use, Ubuntu Server is ideal. If you prefer ease of use, Ubuntu Desktop is fine too.

If you don’t need a graphical interface, Ubuntu Server is more efficient and secure. But if you’re new to Linux or prefer a visual interface, Ubuntu Desktop works just fine too.

Setting up a file server with Ubuntu is simple yet powerful. With the information provided here, you can build a secure, flexible, and efficient file sharing environment tailored to your needs.

8. Conclusion: Achieve Flexible File Sharing with Ubuntu

Building a file server with Ubuntu is a cost-effective and reliable way to set up a stable file-sharing environment over a network. This guide has covered practical topics including Samba and NFS, setup instructions, security practices, and troubleshooting tips.

Choose Between Samba and NFS Based on Your Needs

When it comes to file-sharing methods, the right choice depends on your specific use case.

• Use Samba for sharing with Windows systems
• Accessible directly from Windows Explorer
• Flexible authentication and folder management
• Use NFS for high-speed file sharing between Linux systems
• Lightweight and high-performance
• Perfect for server environments and development teams

You can also use both protocols together depending on your network environment and user requirements. Ubuntu makes it easy to build a mixed setup.

Focus on Security and Maintainability

After setup, keeping your server secure and stable comes down to a few key points:

• Set up firewalls and access controls to prevent unauthorized access
• Keep the system updated and monitor logs to ensure ongoing stability
• Automate backups so you’re prepared for data loss or system failures

Ubuntu offers a wide range of tools and documentation to support all of these practices—even beginners can gradually build solid operational skills.

Why Build Your Own File Server?

Buying a prebuilt NAS (Network Attached Storage) is one option—but building your own file server with Ubuntu offers unique advantages:

• You only install the features you actually need
• You have full control over hardware and storage capacity
• You gain valuable knowledge that can be applied to work or personal projects

If you were worried this would be difficult, we hope this guide showed you that setting everything up from scratch isn’t as hard as it seems.

A file server built with Ubuntu is a versatile tool that can meet the needs of both personal and professional users. Take advantage of its flexibility and design a setup that fits your specific environment and goals.