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SMTP Test

SMTP Test

Test SMTP server settings, TLS or STARTTLS, authentication, and optional test-message delivery.

SMTP Test helps verify the settings used by an application, website, or email client to send mail through an SMTP server. Enter the host, port, security mode, credentials when required, and sender/recipient addresses to test the connection.

By default, the tool performs a connection and authentication test only. Choose Send test email when you want the server to accept a real test message for delivery.

SMTP Test

Enter the required values and run the tool to view results.

Test SMTP server settings with host, port, encryption, optional authentication, and optional test-message delivery. Credentials are used only for this request and are not stored or shown.

SMTP server Port Secure connection Use authentication Username Password Show password Email from Email to Subject Message Test mode

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How to use SMTP Test

Enter the SMTP server hostname, port, secure connection mode, and authentication details supplied by your mail provider. Use port 587 with STARTTLS for most modern submission servers, port 465 for implicit TLS, or port 25 only when testing server-to-server SMTP behavior.

Connection test versus send test

Connection-only mode checks the SMTP banner, EHLO response, TLS negotiation when requested, and authentication when enabled. Send mode continues with MAIL FROM, RCPT TO, DATA, and a test message so you can confirm the server accepts the message. Inbox placement still depends on the recipient provider, spam filters, DNS authentication, and reputation.

Credential handling

SMTP credentials are used only during the current request. The result hides passwords, authentication payloads, and the message body. Do not use a primary account password when your provider supports app passwords or scoped SMTP credentials.

Common troubleshooting signals

A timeout often means the host or port is blocked by firewall rules or the provider does not expose that port publicly. A TLS error usually points to an incorrect security mode or certificate issue. Authentication failures usually mean the username, password, app password, or account security settings need review.

SMTP testing tips

Use the exact settings from your provider. For Gmail, Microsoft 365, and similar providers, basic passwords may not work unless an app password or OAuth-enabled SMTP credential is configured. For domain deliverability, pair this tool with Mail Server Test, SPF lookup, DKIM validation, and DMARC lookup.