FTP and SFTP for file transfer in Computer Networks - Mini Project: Build & Apply

FTP and SFTP for File Transfer

📖 Scenario: You work in a small company that needs to transfer files between computers securely and efficiently. You want to understand how to set up and use two common methods: FTP and SFTP.

🎯 Goal: Build a simple guide that explains the difference between FTP and SFTP, shows how to set up basic configurations, and demonstrates how to transfer files using both methods.

📋 What You'll Learn

Explain what FTP is and create a list of its key features

Explain what SFTP is and create a list of its key features

Show a simple example of FTP file transfer steps

Show a simple example of SFTP file transfer steps

💡 Why This Matters

🌍 Real World

Companies often need to move files between computers or servers. Knowing FTP and SFTP helps choose the right method for secure file transfer.

💼 Career

Network administrators, IT support, and cybersecurity professionals use FTP and SFTP knowledge to manage file transfers safely.

1

Create a list of FTP key features

Create a list called ftp_features containing these exact strings: 'File Transfer Protocol', 'Uses port 21', 'Transfers files in plain text', 'No encryption', 'Faster but less secure'.

Computer Networks

# Create the list ftp_features with the specified FTP features
# Your code here

Hint

Remember to use a Python list with the exact strings given.

2

Create a list of SFTP key features

Create a list called sftp_features containing these exact strings: 'SSH File Transfer Protocol', 'Uses port 22', 'Transfers files encrypted', 'Secure connection', 'Slower but more secure'.

Computer Networks

ftp_features = ['File Transfer Protocol', 'Uses port 21', 'Transfers files in plain text', 'No encryption', 'Faster but less secure']
# Create the list sftp_features with the specified SFTP features
# Your code here

Hint

Use a Python list with the exact strings given for SFTP features.

3

Write the FTP file transfer steps

Create a list called ftp_steps with these exact steps as strings in order: 'Connect to server on port 21', 'Login with username and password', 'Transfer files in plain text', 'Disconnect from server'.

Computer Networks

ftp_features = ['File Transfer Protocol', 'Uses port 21', 'Transfers files in plain text', 'No encryption', 'Faster but less secure']
sftp_features = ['SSH File Transfer Protocol', 'Uses port 22', 'Transfers files encrypted', 'Secure connection', 'Slower but more secure']
# Create the list ftp_steps with the specified FTP file transfer steps
# Your code here

Hint

List the FTP file transfer steps exactly as given.

4

Write the SFTP file transfer steps

Create a list called sftp_steps with these exact steps as strings in order: 'Connect to server on port 22', 'Authenticate with SSH keys or password', 'Transfer files encrypted', 'Disconnect from server'.

Computer Networks

ftp_features = ['File Transfer Protocol', 'Uses port 21', 'Transfers files in plain text', 'No encryption', 'Faster but less secure']
sftp_features = ['SSH File Transfer Protocol', 'Uses port 22', 'Transfers files encrypted', 'Secure connection', 'Slower but more secure']
ftp_steps = ['Connect to server on port 21', 'Login with username and password', 'Transfer files in plain text', 'Disconnect from server']
# Create the list sftp_steps with the specified SFTP file transfer steps
# Your code here

Hint

List the SFTP file transfer steps exactly as given.

Practice

1. Which of the following statements correctly describes the main difference between FTP and SFTP?

easy

A. Neither FTP nor SFTP encrypt data during transfer.

B. SFTP encrypts data during transfer, while FTP does not.

C. Both FTP and SFTP encrypt data equally.

D. FTP encrypts data during transfer, while SFTP does not.

Solution

1. Step 1: Understand FTP security

   FTP is an older protocol that transfers files without encryption, making data vulnerable to interception.

2. Step 2: Understand SFTP security

   SFTP uses encryption to protect data during transfer, making it secure over untrusted networks.

3. Final Answer:

   SFTP encrypts data during transfer, while FTP does not. -> Option B

4. Quick Check:

   Encryption difference = SFTP encrypts, FTP does not [OK]

Hint: Remember: S in SFTP means Secure [OK]

Common Mistakes:

• Thinking FTP encrypts data
• Assuming both protocols are equally secure
• Confusing FTP with FTPS (which adds SSL)

2. Which of the following is the correct command to connect to a server using SFTP in a terminal?

easy

A. ftp [e-mail]

B. ssh [e-mail]

C. scp [e-mail]

D. sftp [e-mail]

Solution

1. Step 1: Identify SFTP command syntax

   The command to start an SFTP session is sftp [e-mail], which initiates a secure file transfer connection.

2. Step 2: Differentiate from other commands

   ftp is for FTP connections, ssh is for remote shell access, and scp copies files but is not an interactive file transfer session.

3. Final Answer:

   sftp [e-mail] -> Option D

4. Quick Check:

   SFTP command starts with 'sftp' [OK]

Hint: SFTP command always starts with 'sftp' [OK]

Common Mistakes:

• Using 'ftp' instead of 'sftp' for secure transfer
• Confusing SSH with SFTP command
• Using SCP which is not interactive

3. Consider this Python snippet using the paramiko library to upload a file via SFTP:

import paramiko
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('example.com', username='user', password='pass')
sftp = client.open_sftp()
sftp.put('local.txt', 'remote.txt')
sftp.close()
client.close()

What will happen when this code runs successfully?

medium

A. The file 'local.txt' is uploaded securely to 'remote.txt' on the server.

B. The file 'remote.txt' is downloaded to 'local.txt' on the client.

C. An error occurs because paramiko does not support SFTP.

D. The connection is made but no file transfer happens.

Solution

1. Step 1: Understand paramiko SFTP usage

   The code connects to the server using SSH, then opens an SFTP session to transfer files securely.

2. Step 2: Analyze the sftp.put method

   sftp.put('local.txt', 'remote.txt') uploads the local file named 'local.txt' to the server as 'remote.txt'.

3. Final Answer:

   The file 'local.txt' is uploaded securely to 'remote.txt' on the server. -> Option A

4. Quick Check:

   sftp.put uploads local to remote [OK]

Hint: sftp.put uploads local file to server [OK]

Common Mistakes:

• Confusing upload with download (put vs get)
• Thinking paramiko does not support SFTP
• Assuming no file transfer happens without error

4. A user tries to connect to a server using SFTP but gets an error: Permission denied (publickey). What is the most likely cause?

medium

A. The SFTP command is not installed on the client machine.

B. The user typed the wrong server address.

C. The server requires a public key for authentication, but the user did not provide one.

D. The file transfer was interrupted by network issues.

Solution

1. Step 1: Interpret the error message

   Permission denied (publickey) means the server expects a public key for login but did not accept any provided or none was given.

2. Step 2: Rule out other causes

   Wrong server address or missing SFTP command would cause different errors. Network interruption would not cause a permission denied error.

3. Final Answer:

   The server requires a public key for authentication, but the user did not provide one. -> Option C

4. Quick Check:

   Public key error means missing or wrong key [OK]

Hint: Permission denied (publickey) means missing SSH key [OK]

Common Mistakes:

• Assuming network issues cause permission denied
• Thinking the command is missing on client
• Confusing server address errors with authentication errors

5. You need to securely transfer multiple files from your local machine to a remote server over an untrusted network. Which approach is best to ensure security and efficiency?

hard

A. Use SFTP to transfer files directly with encryption.

B. Use FTP with a VPN connection to encrypt the data.

C. Use FTP without encryption because it's faster.

D. Use HTTP to upload files through a web browser.

Solution

1. Step 1: Evaluate security needs

   Since the network is untrusted, encryption is necessary to protect data during transfer.

2. Step 2: Compare transfer methods

   SFTP provides built-in encryption and secure authentication, making it ideal for secure file transfer. FTP alone is not secure, even with VPN it adds complexity. HTTP is not designed for secure file transfer.

3. Final Answer:

   Use SFTP to transfer files directly with encryption. -> Option A

4. Quick Check:

   SFTP = secure and efficient file transfer [OK]

Hint: Choose SFTP for secure file transfer over untrusted networks [OK]

Common Mistakes:

• Relying on FTP without encryption
• Assuming VPN always solves FTP security
• Using HTTP which is not meant for file transfer