SMTP Test Tool

Test SMTP server connectivity and configuration

This tool tests SMTP server connectivity without sending actual emails. It checks server response, TLS support, and authentication methods.

SMTP Server Configuration

Enter the SMTP server details to test connectivity

SMTP Server Address

Port

Common SMTP Ports:

Port 25: Standard SMTP (unencrypted)
Port 587: SMTP with STARTTLS (recommended)
Port 465: SMTP over SSL/TLS (legacy)

Ready to Test SMTP Server

Enter an SMTP server address and port above to test connectivity and configuration.

What is SMTP?

SMTP (Simple Mail Transfer Protocol) is the standard protocol for sending emails across the internet. It defines how email messages are transmitted from email clients to email servers and between email servers.

Common SMTP Ports:

Port 25

Standard SMTP port for server-to-server communication. Often blocked by ISPs.

Port 587

SMTP submission port with STARTTLS. Recommended for email clients.

Port 465

SMTP over SSL/TLS (SMTPS). Legacy but still widely used.

How SMTP Works:

Email client connects to SMTP server on specified port
Server responds with banner message and capabilities
Client authenticates with username and password
Client sends email headers and content
Server processes and forwards email to destination

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