Free SMTP Visualizer

Free

Use our free SMTP Visualizer to instantly improve your email workflow. No registration required. Fast, secure, and 100% free.

SMTP Handshake Simulation

Step 1 of 8: 1. TCP Connection (RFC 5321 § 3.1)

Exchange TopologyPlaintext (Port 25)

Client (Sender)

mail.sender.com (203.0.113.42)

Server (Receiver)

mx.example.com (Postfix / Port 25)

Client Request (>)RFC 5321 § 3.1

TCP Connect to Port 25 (mx.example.com)

Server Response (<)

220 mx.example.com ESMTP Postfix (Ubuntu)

How This Step Works

The client establishes a TCP connection on port 25. The mail server accepts the connection and returns its 220 service greeting banner.

Simulation Speed:

Frequently Asked Questions

What is the SMTP Visualizer tool?

The SMTP Visualizer is a free online utility designed to help you quickly and securely process your email tasks without needing complex software.

Is the SMTP Visualizer completely free?

Yes! All utilities on freemailtools.com, including the SMTP Visualizer, are 100% free to use with absolutely no registration required.

Is my data secure when using this tool?

Absolutely. We process data securely and do not store sensitive email content or configurations permanently on our servers.