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
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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