SFTP stands for “Secure File Transfer Protocol,” and an SFTP server is a computer or software system that allows you to securely send and receive files over the internet. Think of it as a digital mailbox where you can securely drop off or pick up files.
Here’s a simple explanation with an example:
Imagine you have important documents that you need to send to your colleague who works in a different city. You can’t physically hand them the documents, so you use an SFTP server instead.
Here’s how it works:

• Server Setup: Your company sets up an SFTP server, like a secure file locker, on a computer or a dedicated server.
• Access Credentials: You’re given a username and a secret password (like a digital key) to access the SFTP server.
• Upload Files: You use special software or a program to connect to the SFTP server. You enter your username and password to access it. Then, you upload your important documents to the server. It’s like putting your files in a virtual safe.
• Secure Transfer: The SFTP server encrypts your files during the transfer. It’s like sealing your documents in a secure envelope before sending them.
• Colleague Access: Your colleague, who also has their own username and password, can log in to the same SFTP server and securely download the documents you uploaded.

This way, your documents are safely and privately sent from one location to another over the internet, protected from prying eyes. SFTP servers are commonly used for sharing sensitive information, backup and restore operations, and secure file exchange between organizations.

Integrating an SFTP (Secure File Transfer Protocol) server in Azure

Integrating an SFTP (Secure File Transfer Protocol) server in Azure typically involves setting up a virtual machine (VM) running an SFTP server software within your Azure environment. Below are step-by-step instructions, including examples, for setting up an SFTP server in Azure:

Step 1: Sign in to Azure Portal
Log in to your Azure portal using your Azure account credentials.

Step 2: Create a Virtual Machine

• Click on the “+ Create a resource” button in the Azure portal.
• Search for “Virtual Machine” and select it from the search results.
• Click the “Create” button to start configuring your VM.
• Fill out the basic VM settings, such as the subscription, resource group, region, and VM name. For example:
• Subscription: Choose your Azure subscription.
• Resource group: Create a new or select an existing one.
• Region: Choose the region where you want to deploy your VM.
• Virtual machine name: Provide a unique name for your VM.
• Click “Next” to configure the virtual machine settings, such as size, authentication, and disk settings. Ensure you select a VM size appropriate for your needs.
• In the “Authentication” section, select “SSH public key” and provide your SSH public key. This key will be used to secure your VM. You can create an SSH key pair using tools like PuTTYgen or the ssh-keygen command.
• Complete the remaining settings, review your configurations, and click “Review + create.”
• After reviewing, click “Create” to deploy the VM.

Step 3: Configure Network Security Group (NSG) Rules
To allow SFTP traffic to reach your VM, you’ll need to configure Network Security Group (NSG) rules:

• In the Azure portal, navigate to your VM resource.
• Under “Settings,” select “Networking.”
• In the Networking pane, click “Add inbound port rule” to add a rule to allow SFTP traffic (port 22 by default).
• Specify the rule details. For example:
• Source: Any
• Source port ranges: *
• Destination: Any
• Destination port ranges: 22 (for SFTP)
• Protocol: TCP
• Action: Allow
• Click “Add” to create the rule.

Step 4: Install and Configure the SFTP Server Software
You can choose from various SFTP server software options. In this example, we’ll use OpenSSH as it’s commonly available and secure:

• SSH into your Azure VM using the private key associated with the public key you provided during VM creation:

ssh username@public-ip-of-your-vm

• Once connected to the VM, install the OpenSSH server:

sudo apt-get update
sudo apt-get install openssh-server

• Configure the SFTP server by editing the SSH configuration file:

sudo nano /etc/ssh/sshd_config

Ensure the following line is present and uncommented (remove the ‘#’ if it exists):

Subsystem sftp /usr/lib/openssh/sftp-server

• Restart the SSH service:

sudo service ssh restart

Step 5: Test the SFTP Server
You can now test the SFTP server:

• From your local machine, use an SFTP client (e.g., WinSCP, FileZilla) to connect to your Azure VM’s public IP address using the SSH private key.
• Use your Azure VM’s username and private key to authenticate.
• You should now be able to transfer files securely between your local machine and the Azure VM using SFTP.

Step 6: Secure and Monitor Your SFTP Server
Ensure you follow best practices for securing your SFTP server, such as regularly updating software and managing user access.
Additionally, consider implementing monitoring and alerting solutions to keep an eye on your SFTP server’s health and performance.
Remember that Azure offers managed services like Azure Blob Storage and Azure Data Factory, which can be used for secure and scalable file storage and data transfer, potentially eliminating the need to set up your own SFTP server.