FTP and SFTP for file transfer in Computer Networks - Step-by-Step Execution

Concept Flow - FTP and SFTP for file transfer

Start: User wants to transfer files

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Choose Protocol: FTP or SFTP

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FTP Protocol

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Connect to Server

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Send Commands

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Transfer Files

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Close Connection

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End

User chooses FTP or SFTP to connect to a server, send commands, transfer files, then close the connection.

Execution Sample

Computer Networks

Connect to server using FTP
Login with username and password
Send command to upload file
File transfers over network
Close FTP connection

This shows the basic steps of transferring a file using FTP.

Analysis Table

Step	Action	Protocol	Result	Notes
1	User initiates connection	FTP	Connection established	Server accepts FTP connection on port 21
2	User logs in	FTP	Login successful	Username and password sent in plain text
3	User sends upload command	FTP	Server ready to receive file	Command: STOR filename
4	File data sent	FTP	File transferred	Data sent over separate data connection
5	Connection closed	FTP	Session ended	User disconnects
6	User initiates connection	SFTP	Connection established	Server accepts SFTP connection on port 22
7	User authenticates	SFTP	Login successful	Authentication encrypted via SSH
8	User sends upload command	SFTP	Server ready to receive file	Command sent over encrypted channel
9	File data sent	SFTP	File transferred	Data encrypted during transfer
10	Connection closed	SFTP	Session ended	User disconnects securely

💡 File transfer completes and connection closes for both FTP and SFTP

State Tracker

Variable	Start	After FTP Login	After FTP Upload	After FTP Close	After SFTP Login	After SFTP Upload	After SFTP Close
Connection Status	Disconnected	Connected	Connected	Disconnected	Connected	Connected	Disconnected
Authentication	None	Plain text	Plain text	None	Encrypted	Encrypted	None
File Transfer Status	Not started	Not started	In progress	Completed	Not started	In progress	Completed

Key Insights - 3 Insights

Why is FTP considered less secure than SFTP?

FTP sends login details and file data in plain text (see execution_table rows 2 and 4), making it easy to intercept. SFTP encrypts all data (rows 7 and 9), protecting information.

Why does FTP use two connections while SFTP uses one?

FTP opens a separate data connection for file transfer (row 4), while SFTP transfers commands and data over a single encrypted SSH connection (rows 8 and 9).

What happens if the connection is lost during file transfer?

The transfer stops and the session ends without completing the file upload (implied by exit_note). Both protocols require reconnecting to resume.

Visual Quiz - 3 Questions

Look at the execution_table at step 2 for FTP. What is the security status of the login?

A Login details are sent encrypted

B Login details are sent in plain text

C No login is required

D Login uses a token

💡 Hint

Check the 'Notes' column for step 2 in the execution_table

At which step does SFTP start transferring the file data?

A Step 9

B Step 8

C Step 7

D Step 10

💡 Hint

Look for 'File data sent' action under SFTP in the execution_table

If FTP used encryption like SFTP, which variable in variable_tracker would change after login?

A Connection Status

B File Transfer Status

C Authentication

D None

💡 Hint

Check the 'Authentication' variable values before and after login in variable_tracker

Concept Snapshot

FTP and SFTP are protocols to transfer files over a network.
FTP uses two connections and sends data unencrypted.
SFTP uses one encrypted connection via SSH.
SFTP is more secure and preferred for sensitive data.
Both require login and support commands to upload/download files.

Full Transcript

This visual execution trace shows how FTP and SFTP protocols work for file transfer. The user starts by choosing a protocol, then connects to the server. FTP connects on port 21 and sends login details in plain text, while SFTP connects on port 22 and encrypts all communication. Both protocols send commands to upload files and transfer data, but FTP uses a separate data connection and SFTP uses a single encrypted channel. After file transfer, the connection closes. The variable tracker shows connection status, authentication method, and file transfer progress at each step. Key moments highlight FTP's lack of security, the difference in connection usage, and what happens if connection is lost. The quiz tests understanding of login security, file transfer steps, and authentication changes. The snapshot summarizes the main points: FTP is older and less secure, SFTP is encrypted and safer for file transfers.