SMTP Tester
Understand what SMTP testing involves and learn about the key checks that ensure your email server is properly configured.
How to Use SMTP Tester
Enter SMTP host
Type your domain name into the input field to identify the mail server configuration.
Test connection
Click Analyze to review all SMTP checks including MX records, SPF, DKIM, DMARC, and TLS.
View configuration
Get a detailed overview of each check with explanations of what a full SMTP test verifies.
Why Use SMTP Tester
TLS/SSL Testing
Verifies STARTTLS support, certificate validity, TLS version, and cipher strength for secure email transit.
Authentication Verification
Checks SPF, DKIM, and DMARC records to ensure your domain email authentication is properly configured.
Port Scanning
Tests connectivity on standard SMTP ports including 25, 465, and 587 for submission and relay.
Connection Diagnostics
Analyzes MX records, EHLO handshake, and server response codes to identify connectivity issues.
Response Code Analysis
Interprets SMTP response codes like 220, 250, and 550 to diagnose server configuration problems.
Privacy Focused
All configuration analysis runs in your browser. No credentials or sensitive data are transmitted.
Who Uses SMTP Tester
DevOps Engineers
Verify mail server configuration after deployment or migration to ensure all authentication records are correct.
Email Admins
Diagnose deliverability issues by checking MX records, SPF alignment, DKIM signatures, and DMARC policies.
Developers
Debug transactional email setup by verifying SMTP connectivity, TLS support, and authentication configuration.
IT Support
Troubleshoot email sending failures by identifying missing DNS records or misconfigured mail server settings.
Need More Power?
Sign up for a free Tomba account to unlock bulk processing, API access, CRM integrations, and 75 free searches per month.
SMTP Tester
If you can't find the answer to your question here, visit the dedicated section in our Help Center .