Online SMTP & Connection Diagnostics
Verify custom mail relay configurations, perform connection latency tests, test STARTTLS security wrappers, audit authentication methods (PLAIN, LOGIN), and debug raw SMTP logs instantly.
Complete SMTP Diagnostic Suite
No more using command-line `telnet` or `openssl` to manually inspect mail servers. Run thorough tests instantly inside our unified staging workspace.
Connection Diagnostics
Validate port configurations (25, 465, 587, 2525) and verify outbound network routes to public SMTP servers (like SendGrid, Mailgun, Amazon SES, or custom VPS relays).
TLS & STARTTLS Inspection
Test encryption security negotiation. Ensure mail servers negotiate correct SSL/TLS sockets and enforce secure handshake handshakes.
Raw Transaction Logs
View the exact transcript of SMTP EHLO, MAIL FROM, RCPT TO, and DATA commands. Identify precise error codes returned by the remote mail exchange.
Frequently Asked Questions
Is my credentials data secure during testing?
Yes, SMTP connection parameters and authentication details are executed live in-memory to establish socket tunnels and are never stored, logged, or cached on our servers.
Can I send attachments during diagnostics?
Yes, our testing suite supports sending standard MIME test payloads including custom body HTML and basic file attachments to verify relay capabilities.