FTP vs. SMTP: Key Protocol Differences Explained

This article breaks down the differences between FTP (File Transfer Protocol) and SMTP (Simple Mail Transfer Protocol). You might also find our comparison of FTP and HTTP helpful.

What is FTP?

FTP, or File Transfer Protocol, is used to send and receive files from a remote computer. It’s defined in RFC959.

FTP establishes two connections between your computer (the client) and the server:

• Control Connection: For commands and responses.
• Data Connection: For the actual file transfer.

Before any files are transferred, you’ll need to authenticate using a username and password. FTP supports both binary and text-based files.

What is SMTP?

SMTP stands for Simple Mail Transfer Protocol. It’s a protocol that allows two computers to exchange electronic mail using a TCP connection. Think of it as the protocol used by email servers to forward messages across the internet.

When you send an email, your computer (the client) uses SMTP to send the email to your local mail server for delivery. It is defined in RFC821, RFC822, and RFC974.

SMTP communicates over the network using the TCP/IP protocol stack, typically using TCP port 25 on the SMTP server.

The communication between the client and server involves short commands (around 4 characters) from the client and 3-digit response codes from the server. These response codes are crucial for debugging any email delivery problems.

Key Difference: File Transfer vs. Email Delivery

The main difference? FTP lets you directly send and receive files to and from a computer. SMTP, on the other hand, is used to deliver email to a user’s mailbox on an email server.

SMTP Response Codes

Here’s a quick rundown of common SMTP response codes:

FTP vs. SMTP: A Side-by-Side Comparison